65 Proximate composition and thermal properties of hemp and flax fibres M. A. Rahman1, M. M. Rahman2*, K. Nemoto3 and A. K. M. Golam Sarwar4 1Department of Bio-science and Food Production, Shinshu University, 8304 Minamiminowa, Nagano 399-4598, Japan. 2Pulp and Paper Research Division, Bangladesh Council of Scientific and Industrial Research, Dhaka 1205, Bangladesh 3Department of Agricultural and Life Sciences, Division of Plant Science and Resources, Shinshu University, 8304 Minamiminowa, Nagano 399-4598, Japan 4Laboratory of Plant Systematics, Department of Crop Botany, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh Abstract Along with the apparel or clothing industry, diversified uses of natural lignocellulosic fibre are getting popularity in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, etc. The property and uses of textiles are determined by their constituent fibre properties. The proximate composition and thermogravimetric analysis (TGA) data of a total of 9 local hemp and flax genotypes (3 and 6, respectively) were carried out to understand their suitability in different applications. A wide variation was observed in the ash content of hemp and flax fibres varied from 1.7 to 17.7%, crude protein 3.27 to 9.02%, crude fibre 26.51 to 55.32%, ether extract 2.6 to 20.9% and energy value 284.44 to 383.96 kcal 100–1 g. In TGA analysis, all the fibres showed a similar trend. The flax genotypes contain lower ash and ether extract and higher DM, crude carbohydrate and crude fibre than hemp genotypes. Therefore, flax could be used in the lightweight composite, textile, pulp and cellulose-based industries. The hemp fibre had higher ash which was reflected by a higher residue at 500oC in TGA analysis. To understand the viability of these flax fibres, further investigations are needed. Keywords: Crude protein; Crude fibre; Ash; Ether extract; Thermogravimetric analysis *Corresponding author e-mail: mmrbcsir3@gmail.com Available online at www.banglajol.info Bangladesh J. Sci. Ind. Res. 58(1), 65-70, 2023 Introduction Natural fibres (NFs), hairlike structures, originated from animals (hairs, wools, silks, etc.), plants (bast, leaf and husk fibres, seed hairs, etc.), or geological processes. These can be used as a component of composites, nonwoven fabrics e.g., felt or paper or, altered into yarns, into woven cloth. The NFs have many advantages in different aspects e.g., environmental pollution, health, etc. over artificial fibres. These NFs are renewable, carbon-neutral, biodegradable and also produce waste that is either organic or can be used to generate electricity or make ecological housing material towards the achievement of UN Sustainable Development Goals (# 12 Responsible Production and Consumption). The demand for commercial use of the NFs and fibre-based composites in various industrial sectors e.g., textile, pulp, automotive interior linings (roof, rear wall, side panel lining), furniture, construction, packaging, and shipping pallets, etc. for their better physicochemical and physicomechanical properties (Girijappa et al. 2019). The quality and use of a natural fibre may vary due to inherent variabilities in its natural components such as fibrous nature, fibre morphology, cellulosic, and non-cellulosic content, and key properties such as fibrous structure, spinnability, strength, fineness, dyeability, and the ability to react with acid or alkali (Shuvo, 2020). Hemp (Cannabis sativa L.; Cannabaceae) and flax (Linum usit at issimum L.; Linaceae), two of the oldest cultivated fibre plants, fibres are singly or combined used for clothing and household textiles (Skoglund et al. 2013). Hemp has also various traditional uses in the Indian subcontinent such as fibre and roasted seeds eaten as a food. In Bangladesh, the hemp plant was cultivated for manufacturing three narcotic products called Ganja, Charas and Bhang (O’Malley, 1916); there are disagreements over the use of hemp fibres. According to O’Malley, hemp was cultivated on 8,000 acres (approx. 3,250 ha) of land of Sitakund on the banks of the Sangu River and in the southeast of Satkania on the banks of Tankabati for producing hemp fibre (O’Malley, 1908). Milburn initially mentioned that hemp has been cultivated in Bengal from time immemorial for intoxication (Milburn, 1813); but is never used by natives for cordage or cloth, as in Europe. However, he also pointed out later that when hemp is intended for cordage, the natives sow it very thin and afterwards transplant the young plants, placing them at a considerable distance from each other, often 2.75 or 3.0 m. The history of commercial hemp cultivation in Bangladesh has been discussed (Rahman et al. 2022). Hemp fibres are used in rope, textiles, garden mulch, an assortment of building materials and animal beddings, to fabricate different composites, and processed to form yarn or bundles (Girijappa et al. 2019). The history of linen production and use dates back to 12000 BC (Vedic age) to 1500 CE (Medieval period) in the Indian subcontinent, including India, Pakistan and Bangladesh <https:// agropedia.i itk.ac.in/ content/history- linen- indian-subcontinent>. Edible flaxseed dominated India’s production rather than fibre flax; because other fibre species, such as hemp, were already in wide use (Judd, 1995). Flax fibres are used in furniture materials, textiles bed sheets, linen, interior decoration accessories, composite reinforcement, etc. (Girijappa et al. 2019; Baley, 2021). The nutritional aspects of both hemp and flax seeds and different plant parts were reported in different publications (Muir and Westcott, 2003; Audu et al. 2014; Galasso et al. Thermogravimetric analysis (TGA) was performed by a thermal analyzer of SII TG/DTA 6300. Thermal analysis was carried out in the temperature range of 30–500°C with a programmed heating rate of 20°C min–1. The inertness of the heating chamber was maintained with continuous nitrogen gas flow at 100 ml min–1. The test was performed with a 5 to 8 mg ground sample in the platinum crucible. Results and discussion Proximate analysis Distinct differences in all the proximate components were observed between fibre of hemp and flax genotypes except the DM content. The results revealed a close similarity in the DM content of hemp and flax fibres which varied from 96% to 97.1% (Table I). High DM content in fibre cells indicates that these are rich in structural components – carbohydrates, protein, fats, minerals, etc. except water. The density of hemp and flax fibres was the same or very similar and low (1.4–1.5 g cm–3) which could be a great choice for light-weight composite structures (Misnon, 2014). Low-density fibre has enormous implications in technical textile industries, especially in aerospace and automotive applications for reducing fuel consumption and related fuel costs (Shuvo et al. 2020). A careful selection of cultivars (/genotypes) would allow for the optimizing utility of this fibre feature (Shuvo, 2020). Ash content was analyzed in the range of 1.7% to 17.7% and a significant difference was observed between hemp (12.5–17.7%) and flax (1.7–3.8%) genotypes. The maximum ash was found in hemp genotype Meherpur and the minimum in flax genotype Chilmari. Ash is the residue left after all the moisture and organic matter has been removed at high temperatures. The high ash content of these fibres is a measure of mineral richness (Lai and Roy, 2004). The maximum quantity of CP, EE and energy value was found in hemp genotypes and minimum in flax genotypes. Fibres of two flax genotypes, viz. BD-10708 and BD-1903, contained an exceptionally higher amount of ether extract compared to others (Table I). In living organisms, fat is the usually stored form of energy. They are the main structural element of phospholipids and sterols (Hashim et al. 2014). The CF and crude carbohydrate (CC) contents showed the maximum value for flax genotype Canada (55.32%) and Nila (38.25%), respectively and a minimum for hemp genotype Brammonbaria (26.51%) and Meherpur (23.86%). The energy value of hemp genotypes was higher and ranged from 337.93 to 383.96 kcal 100–1 g (Table I). This augmented energy value is due to their greater fat content compared with flax genotypes (Ishag et al. 2019). Among the different plant parts of hemp, the leaf possessed the maximum amount (23.78%) of CP (Audu et al. 2014). On the other hand, fibre contains the highest amount of CF (28.29%) and ash (12%); EE (%) of the leaf was identical to that of fibre except in one genotype Brammonbaria (Table I) (Audu et al. 2014). In flax plants, seeds contain the highest amount of CP (21%) and EE (43.17%), and maximum CF (avg. 51.23%) and CC (avg. 33.38%) in fibre (Table I) (Ishag et al. 2019). Thermogravimetric analysis The TGA curves were used to determine the thermal behaviour such as weight loss and residual char level of material at a certain temperature. The thermal behaviour of untreated hemp and flax fibres is shown in Fig. 1. Fibres of all the genot ypea are lignocellulosic and show almost similar thermal degradation patterns. Thermal degradation profiles of the fibres are separated into three different stages. The first stage of degradation started at around 100°C and last up to 180°C. At this stage, about 10% mass loss occurs. Mass loss of fibres at around 100°C due to elimination or rapid evaporation of water during the initial stages of heating (Ouajai and Shanks, 2005). In addition to moisture, some fraction of waxes, pectin, lignin and hemicellulose degraded in this stage (Wielage et al. 1999). Decomposing of both the hemp and flax fibres takes place slowly up to about 250°C. Later the second decomposition started where the maximum mass loss occurred. Maximum decomposition took place between 250 and 350°C due to the depolymerization of cellulose and hemicellulose (Albano et al. 1999). It is obvious from the proximate analysis (Table I) that there is a difference in the chemical composition of the genotypes that affects the thermal stability. The thermal stability of the flax genotypes Chilmari and BD-10708 showed higher than the others. The third stage of decomposition begins at a temperature of about 350°C. At this stage, the fibre breaks down to form chars releasing water and carbon dioxide. With a further increase in temperature, the process of formation and digestion of chars takes place. The stable residual mass at 500°C temperature comes mostly from minerals and char residue (Gashti et al. 2013). Proximate analysis showed that hemp fibre had higher ash content on average than flax fibre (Table I). The TGA analysis also coincides with the proximate analysis showing a higher residual mass fraction at 500°C for hemp fibres. Conclusion The lower ash and ether extract and higher DM, CC and CF of these flax fibres make them (also) suitable for being used in the lightweight composite, textile, pulp and cellulose-based industries. The hemp fibre had higher ash which was reflected by a higher residue at 500°C in TGA analysis. High ash content in the hemp fibres will provide high thermal stability and could be used as reinforcement material for composite. Further investigations are needed to understand the viability of these flax fibres for different purposes. References Albano C, Gonzalez J, Ichazo M and Kaiser D (1999), Thermal stability of blends of polyolefins and sisal fiber, Polym Degrad Stab. 66(2): 179-190. . Alonso-Esteban JI, Pinela J, Ćirić A, Calhelha RC, Soković M, Ferreira IC, Barros L, Torija-Isasa E and de Cortes Sánchez-Mata M (2022), Chemical composition and biological activities of whole and dehulled hemp (Cannabis sativa L.) seeds, Food Chem. 374: 131754. Doi: 10.1016/j.foodchem.2021.131754 Audu BS, Ofojekwu PC, Ujah A and Ajima MNO (2014), Phytochemical, proximate composition, amino acid profile and characterization of Marijuana (Cannabis sativa L.), J Phytopharma. 3(1): 35-43. Baley C, Bourmaud A and Davies P (2021), Eighty years of composites reinforced by flax fibres: A historical review, Composites Part A: Appl Sci Manufac 144: 106333. Doi: 10.1016/j.compositesa.2021.106333 European Parliament and Council of the European Union, (2011), Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, amending Regulations (EC) No 1924/ 2006 and (EC) No 1925/2006 of the European Parliament and of the Council, and repealing Commission Directive 87/250/EEC, Council Directive 90/496/EEC, Commission Directive 1999/10/EC, Directive 2000/13/EC of the European Parliament and of the Council, Commission Directives 2002/67/EC and 2008/5/EC and Commission Regulation (EC) No 608/2004. Official Journal of the European Union, L 304: 18-63. Galasso I, Russo R, Mapelli S, Ponzoni E, Brambilla IM, Battelli G and Reggiani R (2016), Variability in seed traits in a collection of Cannabis sativa L. genotypes, Front Plant Sci. 7: 688. Doi: 10.3389/ fpls. 2016.00688 Gashti MP, Elahi A and Gashti MP (2013), UV radiation inducing succinic acid/silica–kaolinite network on cellulose fiber to improve the functionality, Compos B Eng. 48: 158-166 Girijappa YT, Rangappa SM, Parameswaranpillai J and Siengchin S (2019), Natural fibers as sustainable and renewable resource for development of eco-friendly composites: A comprehensive review, Front Mater 6: 226. Doi: 10.3389/fmats.2019.00226 Hashim S, Bakht T, Marwat KB and Jan A (2014), Medicinal properties, phytochemistry and pharmacology of Tribulus terrestris L. (Zygophyllaceae), Pak J Bot. 46(1): 399-404. . Ishag OAO, Khalid AA, Abdi A, Erwa IY, Omer AB and Nour AH (2019), Proximate composition, physicochemical properties and antioxidant activity of Flaxseed, Annl Res Rev Biol. 34(2): 1-10. Judd A (1995), Flaxseed in Human Nutrition. eds by S.C. Cunnane, L.U. Thompson. (AOCS Press, Champaign, IL) 1995, pp 1-10. Kabir AA, Moniruzzaman M, Gulshan Z, Rahman AM and Sarwar AKM Golam (2018), Biomass yield, chemical composition and in vitro gas production of different dhaincha (Sesbania spp.) Accessions from Bangladesh, Indian Anim Nutri. 35(4): 397-402. Doi: 10.5958/2231-6744.2018.00060.9 Lai PK and Roy J (2004), Antimicrobial and chemopreventive properties of herbs and spices, Curr Med Chem. 11(11): 1451-1460. Milburn W (1813), Oriental Commerce.Vol. 2 (Black, Parry & Co, London) 1813, pp 209-11. Misnon MI, Islam MM, Epaarachchi JA and Lau KT (2014), Potentiality of utilising natural textile materials for engineering composites applications, Mater Des. 59: 359-368. Doi: 10.1016/j.matdes.2014.03.022 Muir AD and Westcott ND (2003), Flax: the genus Linum. (CRC press) 2003. Mundaragi A, Devarajan T, Bhat S and Jeyabalan S (2017), Proximate analysis and mineral composition of potential minor fruits of Western Ghats of India. Scientific Papers. Series A. Agronomy, LX., pp 340-346. O’Malley LSS (1916), Bengal district gazetteers: Rajshahi. (Bengal Secretariat Book Depot, Calcutta) 1996, pp 134-144 O'Malley LSS (1908), Eastern Bengal District Gazetteers: Chittagong (Bengal Secretariat Book Depot, Calcutta) 1908. Ouajai S and Shanks RA (2005), Composition, structure and thermal degradation of hemp cellulose after chemical treatments, Polym Degrad Stab. 89(2): 327-335. Rahman AM, Nemoto K, Matsushima KI, Uddin SB and Sarwar AKM Golam (2022), A history of cannabis (Ganja) as an economic crop in Bangladesh from the late 18th century to 1989, Trop Agric Develop 66(1): 21-32. Doi: 10.9790/0837-2509041926 Roy S, Ali M, Amin MN, Jianguang S, Bhattacharya SK, Sen HS, Sur D, Lutfar LB, Rahman MS, Hassan DS (2010), Jute Basics, International Jute Study Group, Monipuri Para, Dhaka. Shuvo II (2020), Fibre attributes and mapping the cultivar influence of different industrial cellulosic crops (cotton, hemp, flax, and canola) on textile properties, Bioresour Bioprocess 7(51): 1-28. Doi: 10.1177/ 0040517519886636 Shuvo II, Rahman M, Vahora T, Morrison J, DuCharme S and Choo-Smith LPI (2020), Producing light-weight bast fibers from canola biomass for technical textiles, Tex Res J. 90(11-12): 1311-1325. Doi: 10.1186/ s40643-020-00339-1 Skoglund G, Nockert M and Holst B (2013), Viking and early Middle Ages northern Scandinavian textiles proven to be made with hemp, Sci Rep. 3(1): 1-6. Doi: 10.1038/srep02686 Waris Z, Iqbal Y, Arshad Hussain S, Khan AA, Ali A and Khan MW (2018), Proximate composition, phytochemical analysis and antioxidant capacity of Aloe vera, Cannabis sativa and Mentha longifolia, Pure Appl Biol. 7(3): 1122-1130. Doi: 10.19045/ bspab.2018.700131 Wielage B, Lampke T, Marx G, Nestler K and Starke D (1999), Thermogravimetric and differential scanning calorimetric analysis of natural fibres and polypropylene, Thermochimica Acta. 337(1-2): 169-177. DOI: https://doi.org/10.3329/bjsir.v58i1.64236 Received: 01 February 2023 Revised: 15 February 2023 Accepted: 19 February 2023 2016; Waris et al. 2018; Ishag et al. 2019; Alonso-Esteban et al. 2022). Although the physical properties of hemp and flax fibres are known to us (Girijappa et al. 2019), hitherto, no information on the proximate composition of fibres of Bangladeshi genotypes of these two important fibre-yielding crops is available. The constituent fibre properties influence application of textiles in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, as well as the apparel or clothing industry (Shuvo, 2020). We have, therefore, reported the proximate composition and thermogravimetric analysis data of 3 hemp and 6 flax genotypes here. Materials and methods The proximate analysis and thermogravimetric analysis (of fibres) of six flax genotypes and three hemp genotypes were carried out to understand their suitability in different applications. Hemp seeds were collected from different locations in Bangladesh (detailed collection information will be available upon request) and the genotypes are named accordingly, viz. Brammonbaria, Chittagang and Meherpur. The hemp plants were grown (in a confined area) at Botanical Garden, Department of Crop Botany, Bangladesh Agricultural University. Flax fibres were collected with the ribbon retting method (Roy et al. 2010) and sun-dried properly. The flax fibres of 6 genotypes, harvested from another experiment in the same year, were collected from the Laboratory of Plant Systematics of the same Department. The proximate composition analysis viz. dry matter (DM), crude protein (CP), crude fibre (CF), ash and ether extract (crude fat; EE), were accomplished at the Laboratory of Department of Animal Science, Bangladesh Agricultural University, Mymensingh following standard procedure (Kabir et al. 2018). The crude carbohydrate was calculated following Mundaragi et al. (2017). Crude Carbohydrate (%) = 100 – [moisture (%) + protein (%) + fibre (%) + fat (%) + ash (%)] The calorific value or the total energy value of fruits in kcal100–1 g was calculated with the help of the following equation (European Parliament and Council of the European Union, 2011). Energy value (kcal 100–1 g) = 4 × Protein + 9 × Fat + 4 × Carbohydrate + 2 × Fibre Short Communication Proximate composition and thermal properties of hemp and flax fibres 58(1) 202366 furniture, construction, packaging, and shipping pallets, etc. for their better physicochemical and physicomechanical properties (Girijappa et al. 2019). The quality and use of a natural fibre may vary due to inherent variabilities in its natural components such as fibrous nature, fibre morphology, cellulosic, and non-cellulosic content, and key properties such as fibrous structure, spinnability, strength, fineness, dyeability, and the ability to react with acid or alkali (Shuvo, 2020). Hemp (Cannabis sativa L.; Cannabaceae) and flax (Linum usit at issimum L.; Linaceae), two of the oldest cultivated fibre plants, fibres are singly or combined used for clothing and household textiles (Skoglund et al. 2013). Hemp has also various traditional uses in the Indian subcontinent such as fibre and roasted seeds eaten as a food. In Bangladesh, the hemp plant was cultivated for manufacturing three narcotic products called Ganja, Charas and Bhang (O’Malley, 1916); there are disagreements over the use of hemp fibres. According to O’Malley, hemp was cultivated on 8,000 acres (approx. 3,250 ha) of land of Sitakund on the banks of the Sangu River and in the southeast of Satkania on the banks of Tankabati for producing hemp fibre (O’Malley, 1908). Milburn initially mentioned that hemp has been cultivated in Bengal from time immemorial for intoxication (Milburn, 1813); but is never used by natives for cordage or cloth, as in Europe. However, he also pointed out later that when hemp is intended for cordage, the natives sow it very thin and afterwards transplant the young plants, placing them at a considerable distance from each other, often 2.75 or 3.0 m. The history of commercial hemp cultivation in Bangladesh has been discussed (Rahman et al. 2022). Hemp fibres are used in rope, textiles, garden mulch, an assortment of building materials and animal beddings, to fabricate different composites, and processed to form yarn or bundles (Girijappa et al. 2019). The history of linen production and use dates back to 12000 BC (Vedic age) to 1500 CE (Medieval period) in the Indian subcontinent, including India, Pakistan and Bangladesh <https:// agropedia.i itk.ac.in/ content/history- linen- indian-subcontinent>. Edible flaxseed dominated India’s production rather than fibre flax; because other fibre species, such as hemp, were already in wide use (Judd, 1995). Flax fibres are used in furniture materials, textiles bed sheets, linen, interior decoration accessories, composite reinforcement, etc. (Girijappa et al. 2019; Baley, 2021). The nutritional aspects of both hemp and flax seeds and different plant parts were reported in different publications (Muir and Westcott, 2003; Audu et al. 2014; Galasso et al. Thermogravimetric analysis (TGA) was performed by a thermal analyzer of SII TG/DTA 6300. Thermal analysis was carried out in the temperature range of 30–500°C with a programmed heating rate of 20°C min–1. The inertness of the heating chamber was maintained with continuous nitrogen gas flow at 100 ml min–1. The test was performed with a 5 to 8 mg ground sample in the platinum crucible. Results and discussion Proximate analysis Distinct differences in all the proximate components were observed between fibre of hemp and flax genotypes except the DM content. The results revealed a close similarity in the DM content of hemp and flax fibres which varied from 96% to 97.1% (Table I). High DM content in fibre cells indicates that these are rich in structural components – carbohydrates, protein, fats, minerals, etc. except water. The density of hemp and flax fibres was the same or very similar and low (1.4–1.5 g cm–3) which could be a great choice for light-weight composite structures (Misnon, 2014). Low-density fibre has enormous implications in technical textile industries, especially in aerospace and automotive applications for reducing fuel consumption and related fuel costs (Shuvo et al. 2020). A careful selection of cultivars (/genotypes) would allow for the optimizing utility of this fibre feature (Shuvo, 2020). Ash content was analyzed in the range of 1.7% to 17.7% and a significant difference was observed between hemp (12.5–17.7%) and flax (1.7–3.8%) genotypes. The maximum ash was found in hemp genotype Meherpur and the minimum in flax genotype Chilmari. Ash is the residue left after all the moisture and organic matter has been removed at high temperatures. The high ash content of these fibres is a measure of mineral richness (Lai and Roy, 2004). The maximum quantity of CP, EE and energy value was found in hemp genotypes and minimum in flax genotypes. Fibres of two flax genotypes, viz. BD-10708 and BD-1903, contained an exceptionally higher amount of ether extract compared to others (Table I). In living organisms, fat is the usually stored form of energy. They are the main structural element of phospholipids and sterols (Hashim et al. 2014). The CF and crude carbohydrate (CC) contents showed the maximum value for flax genotype Canada (55.32%) and Nila (38.25%), respectively and a minimum for hemp genotype Brammonbaria (26.51%) and Meherpur (23.86%). The energy value of hemp genotypes was higher and ranged from 337.93 to 383.96 kcal 100–1 g (Table I). This augmented energy value is due to their greater fat content compared with flax genotypes (Ishag et al. 2019). Among the different plant parts of hemp, the leaf possessed the maximum amount (23.78%) of CP (Audu et al. 2014). On the other hand, fibre contains the highest amount of CF (28.29%) and ash (12%); EE (%) of the leaf was identical to that of fibre except in one genotype Brammonbaria (Table I) (Audu et al. 2014). In flax plants, seeds contain the highest amount of CP (21%) and EE (43.17%), and maximum CF (avg. 51.23%) and CC (avg. 33.38%) in fibre (Table I) (Ishag et al. 2019). Thermogravimetric analysis The TGA curves were used to determine the thermal behaviour such as weight loss and residual char level of material at a certain temperature. The thermal behaviour of untreated hemp and flax fibres is shown in Fig. 1. Fibres of all the genot ypea are lignocellulosic and show almost similar thermal degradation patterns. Thermal degradation profiles of the fibres are separated into three different stages. The first stage of degradation started at around 100°C and last up to 180°C. At this stage, about 10% mass loss occurs. Mass loss of fibres at around 100°C due to elimination or rapid evaporation of water during the initial stages of heating (Ouajai and Shanks, 2005). In addition to moisture, some fraction of waxes, pectin, lignin and hemicellulose degraded in this stage (Wielage et al. 1999). Decomposing of both the hemp and flax fibres takes place slowly up to about 250°C. Later the second decomposition started where the maximum mass loss occurred. Maximum decomposition took place between 250 and 350°C due to the depolymerization of cellulose and hemicellulose (Albano et al. 1999). It is obvious from the proximate analysis (Table I) that there is a difference in the chemical composition of the genotypes that affects the thermal stability. The thermal stability of the flax genotypes Chilmari and BD-10708 showed higher than the others. The third stage of decomposition begins at a temperature of about 350°C. At this stage, the fibre breaks down to form chars releasing water and carbon dioxide. With a further increase in temperature, the process of formation and digestion of chars takes place. The stable residual mass at 500°C temperature comes mostly from minerals and char residue (Gashti et al. 2013). Proximate analysis showed that hemp fibre had higher ash content on average than flax fibre (Table I). The TGA analysis also coincides with the proximate analysis showing a higher residual mass fraction at 500°C for hemp fibres. Conclusion The lower ash and ether extract and higher DM, CC and CF of these flax fibres make them (also) suitable for being used in the lightweight composite, textile, pulp and cellulose-based industries. The hemp fibre had higher ash which was reflected by a higher residue at 500°C in TGA analysis. High ash content in the hemp fibres will provide high thermal stability and could be used as reinforcement material for composite. Further investigations are needed to understand the viability of these flax fibres for different purposes. References Albano C, Gonzalez J, Ichazo M and Kaiser D (1999), Thermal stability of blends of polyolefins and sisal fiber, Polym Degrad Stab. 66(2): 179-190. . Alonso-Esteban JI, Pinela J, Ćirić A, Calhelha RC, Soković M, Ferreira IC, Barros L, Torija-Isasa E and de Cortes Sánchez-Mata M (2022), Chemical composition and biological activities of whole and dehulled hemp (Cannabis sativa L.) seeds, Food Chem. 374: 131754. Doi: 10.1016/j.foodchem.2021.131754 Audu BS, Ofojekwu PC, Ujah A and Ajima MNO (2014), Phytochemical, proximate composition, amino acid profile and characterization of Marijuana (Cannabis sativa L.), J Phytopharma. 3(1): 35-43. Baley C, Bourmaud A and Davies P (2021), Eighty years of composites reinforced by flax fibres: A historical review, Composites Part A: Appl Sci Manufac 144: 106333. Doi: 10.1016/j.compositesa.2021.106333 European Parliament and Council of the European Union, (2011), Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, amending Regulations (EC) No 1924/ 2006 and (EC) No 1925/2006 of the European Parliament and of the Council, and repealing Commission Directive 87/250/EEC, Council Directive 90/496/EEC, Commission Directive 1999/10/EC, Directive 2000/13/EC of the European Parliament and of the Council, Commission Directives 2002/67/EC and 2008/5/EC and Commission Regulation (EC) No 608/2004. Official Journal of the European Union, L 304: 18-63. Galasso I, Russo R, Mapelli S, Ponzoni E, Brambilla IM, Battelli G and Reggiani R (2016), Variability in seed traits in a collection of Cannabis sativa L. genotypes, Front Plant Sci. 7: 688. Doi: 10.3389/ fpls. 2016.00688 Gashti MP, Elahi A and Gashti MP (2013), UV radiation inducing succinic acid/silica–kaolinite network on cellulose fiber to improve the functionality, Compos B Eng. 48: 158-166 Girijappa YT, Rangappa SM, Parameswaranpillai J and Siengchin S (2019), Natural fibers as sustainable and renewable resource for development of eco-friendly composites: A comprehensive review, Front Mater 6: 226. Doi: 10.3389/fmats.2019.00226 Hashim S, Bakht T, Marwat KB and Jan A (2014), Medicinal properties, phytochemistry and pharmacology of Tribulus terrestris L. (Zygophyllaceae), Pak J Bot. 46(1): 399-404. . Ishag OAO, Khalid AA, Abdi A, Erwa IY, Omer AB and Nour AH (2019), Proximate composition, physicochemical properties and antioxidant activity of Flaxseed, Annl Res Rev Biol. 34(2): 1-10. Judd A (1995), Flaxseed in Human Nutrition. eds by S.C. Cunnane, L.U. Thompson. (AOCS Press, Champaign, IL) 1995, pp 1-10. Kabir AA, Moniruzzaman M, Gulshan Z, Rahman AM and Sarwar AKM Golam (2018), Biomass yield, chemical composition and in vitro gas production of different dhaincha (Sesbania spp.) Accessions from Bangladesh, Indian Anim Nutri. 35(4): 397-402. Doi: 10.5958/2231-6744.2018.00060.9 Lai PK and Roy J (2004), Antimicrobial and chemopreventive properties of herbs and spices, Curr Med Chem. 11(11): 1451-1460. Milburn W (1813), Oriental Commerce.Vol. 2 (Black, Parry & Co, London) 1813, pp 209-11. Misnon MI, Islam MM, Epaarachchi JA and Lau KT (2014), Potentiality of utilising natural textile materials for engineering composites applications, Mater Des. 59: 359-368. Doi: 10.1016/j.matdes.2014.03.022 Muir AD and Westcott ND (2003), Flax: the genus Linum. (CRC press) 2003. Mundaragi A, Devarajan T, Bhat S and Jeyabalan S (2017), Proximate analysis and mineral composition of potential minor fruits of Western Ghats of India. Scientific Papers. Series A. Agronomy, LX., pp 340-346. O’Malley LSS (1916), Bengal district gazetteers: Rajshahi. (Bengal Secretariat Book Depot, Calcutta) 1996, pp 134-144 O'Malley LSS (1908), Eastern Bengal District Gazetteers: Chittagong (Bengal Secretariat Book Depot, Calcutta) 1908. Ouajai S and Shanks RA (2005), Composition, structure and thermal degradation of hemp cellulose after chemical treatments, Polym Degrad Stab. 89(2): 327-335. Rahman AM, Nemoto K, Matsushima KI, Uddin SB and Sarwar AKM Golam (2022), A history of cannabis (Ganja) as an economic crop in Bangladesh from the late 18th century to 1989, Trop Agric Develop 66(1): 21-32. Doi: 10.9790/0837-2509041926 Roy S, Ali M, Amin MN, Jianguang S, Bhattacharya SK, Sen HS, Sur D, Lutfar LB, Rahman MS, Hassan DS (2010), Jute Basics, International Jute Study Group, Monipuri Para, Dhaka. Shuvo II (2020), Fibre attributes and mapping the cultivar influence of different industrial cellulosic crops (cotton, hemp, flax, and canola) on textile properties, Bioresour Bioprocess 7(51): 1-28. Doi: 10.1177/ 0040517519886636 Shuvo II, Rahman M, Vahora T, Morrison J, DuCharme S and Choo-Smith LPI (2020), Producing light-weight bast fibers from canola biomass for technical textiles, Tex Res J. 90(11-12): 1311-1325. Doi: 10.1186/ s40643-020-00339-1 Skoglund G, Nockert M and Holst B (2013), Viking and early Middle Ages northern Scandinavian textiles proven to be made with hemp, Sci Rep. 3(1): 1-6. Doi: 10.1038/srep02686 Waris Z, Iqbal Y, Arshad Hussain S, Khan AA, Ali A and Khan MW (2018), Proximate composition, phytochemical analysis and antioxidant capacity of Aloe vera, Cannabis sativa and Mentha longifolia, Pure Appl Biol. 7(3): 1122-1130. Doi: 10.19045/ bspab.2018.700131 Wielage B, Lampke T, Marx G, Nestler K and Starke D (1999), Thermogravimetric and differential scanning calorimetric analysis of natural fibres and polypropylene, Thermochimica Acta. 337(1-2): 169-177. 2016; Waris et al. 2018; Ishag et al. 2019; Alonso-Esteban et al. 2022). Although the physical properties of hemp and flax fibres are known to us (Girijappa et al. 2019), hitherto, no information on the proximate composition of fibres of Bangladeshi genotypes of these two important fibre-yielding crops is available. The constituent fibre properties influence application of textiles in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, as well as the apparel or clothing industry (Shuvo, 2020). We have, therefore, reported the proximate composition and thermogravimetric analysis data of 3 hemp and 6 flax genotypes here. Materials and methods The proximate analysis and thermogravimetric analysis (of fibres) of six flax genotypes and three hemp genotypes were carried out to understand their suitability in different applications. Hemp seeds were collected from different locations in Bangladesh (detailed collection information will be available upon request) and the genotypes are named accordingly, viz. Brammonbaria, Chittagang and Meherpur. The hemp plants were grown (in a confined area) at Botanical Garden, Department of Crop Botany, Bangladesh Agricultural University. Flax fibres were collected with the ribbon retting method (Roy et al. 2010) and sun-dried properly. The flax fibres of 6 genotypes, harvested from another experiment in the same year, were collected from the Laboratory of Plant Systematics of the same Department. The proximate composition analysis viz. dry matter (DM), crude protein (CP), crude fibre (CF), ash and ether extract (crude fat; EE), were accomplished at the Laboratory of Department of Animal Science, Bangladesh Agricultural University, Mymensingh following standard procedure (Kabir et al. 2018). The crude carbohydrate was calculated following Mundaragi et al. (2017). Crude Carbohydrate (%) = 100 – [moisture (%) + protein (%) + fibre (%) + fat (%) + ash (%)] The calorific value or the total energy value of fruits in kcal100–1 g was calculated with the help of the following equation (European Parliament and Council of the European Union, 2011). Energy value (kcal 100–1 g) = 4 × Protein + 9 × Fat + 4 × Carbohydrate + 2 × Fibre Rahman, Rahman, Nemoto and Sarwar 67 furniture, construction, packaging, and shipping pallets, etc. for their better physicochemical and physicomechanical properties (Girijappa et al. 2019). The quality and use of a natural fibre may vary due to inherent variabilities in its natural components such as fibrous nature, fibre morphology, cellulosic, and non-cellulosic content, and key properties such as fibrous structure, spinnability, strength, fineness, dyeability, and the ability to react with acid or alkali (Shuvo, 2020). Hemp (Cannabis sativa L.; Cannabaceae) and flax (Linum usit at issimum L.; Linaceae), two of the oldest cultivated fibre plants, fibres are singly or combined used for clothing and household textiles (Skoglund et al. 2013). Hemp has also various traditional uses in the Indian subcontinent such as fibre and roasted seeds eaten as a food. In Bangladesh, the hemp plant was cultivated for manufacturing three narcotic products called Ganja, Charas and Bhang (O’Malley, 1916); there are disagreements over the use of hemp fibres. According to O’Malley, hemp was cultivated on 8,000 acres (approx. 3,250 ha) of land of Sitakund on the banks of the Sangu River and in the southeast of Satkania on the banks of Tankabati for producing hemp fibre (O’Malley, 1908). Milburn initially mentioned that hemp has been cultivated in Bengal from time immemorial for intoxication (Milburn, 1813); but is never used by natives for cordage or cloth, as in Europe. However, he also pointed out later that when hemp is intended for cordage, the natives sow it very thin and afterwards transplant the young plants, placing them at a considerable distance from each other, often 2.75 or 3.0 m. The history of commercial hemp cultivation in Bangladesh has been discussed (Rahman et al. 2022). Hemp fibres are used in rope, textiles, garden mulch, an assortment of building materials and animal beddings, to fabricate different composites, and processed to form yarn or bundles (Girijappa et al. 2019). The history of linen production and use dates back to 12000 BC (Vedic age) to 1500 CE (Medieval period) in the Indian subcontinent, including India, Pakistan and Bangladesh <https:// agropedia.i itk.ac.in/ content/history- linen- indian-subcontinent>. Edible flaxseed dominated India’s production rather than fibre flax; because other fibre species, such as hemp, were already in wide use (Judd, 1995). Flax fibres are used in furniture materials, textiles bed sheets, linen, interior decoration accessories, composite reinforcement, etc. (Girijappa et al. 2019; Baley, 2021). The nutritional aspects of both hemp and flax seeds and different plant parts were reported in different publications (Muir and Westcott, 2003; Audu et al. 2014; Galasso et al. Thermogravimetric analysis (TGA) was performed by a thermal analyzer of SII TG/DTA 6300. Thermal analysis was carried out in the temperature range of 30–500°C with a programmed heating rate of 20°C min–1. The inertness of the heating chamber was maintained with continuous nitrogen gas flow at 100 ml min–1. The test was performed with a 5 to 8 mg ground sample in the platinum crucible. Results and discussion Proximate analysis Distinct differences in all the proximate components were observed between fibre of hemp and flax genotypes except the DM content. The results revealed a close similarity in the DM content of hemp and flax fibres which varied from 96% to 97.1% (Table I). High DM content in fibre cells indicates that these are rich in structural components – carbohydrates, protein, fats, minerals, etc. except water. The density of hemp and flax fibres was the same or very similar and low (1.4–1.5 g cm–3) which could be a great choice for light-weight composite structures (Misnon, 2014). Low-density fibre has enormous implications in technical textile industries, especially in aerospace and automotive applications for reducing fuel consumption and related fuel costs (Shuvo et al. 2020). A careful selection of cultivars (/genotypes) would allow for the optimizing utility of this fibre feature (Shuvo, 2020). Ash content was analyzed in the range of 1.7% to 17.7% and a significant difference was observed between hemp (12.5–17.7%) and flax (1.7–3.8%) genotypes. The maximum ash was found in hemp genotype Meherpur and the minimum in flax genotype Chilmari. Ash is the residue left after all the moisture and organic matter has been removed at high temperatures. The high ash content of these fibres is a measure of mineral richness (Lai and Roy, 2004). The maximum quantity of CP, EE and energy value was found in hemp genotypes and minimum in flax genotypes. Fibres of two flax genotypes, viz. BD-10708 and BD-1903, contained an exceptionally higher amount of ether extract compared to others (Table I). In living organisms, fat is the usually stored form of energy. They are the main structural element of phospholipids and sterols (Hashim et al. 2014). The CF and crude carbohydrate (CC) contents showed the maximum value for flax genotype Canada (55.32%) and Nila (38.25%), respectively and a minimum for hemp genotype Brammonbaria (26.51%) and Meherpur (23.86%). The energy value of hemp genotypes was higher and ranged from 337.93 to 383.96 kcal 100–1 g (Table I). This augmented energy value is due to their greater fat content compared with flax genotypes (Ishag et al. 2019). Among the different plant parts of hemp, the leaf possessed the maximum amount (23.78%) of CP (Audu et al. 2014). On the other hand, fibre contains the highest amount of CF (28.29%) and ash (12%); EE (%) of the leaf was identical to that of fibre except in one genotype Brammonbaria (Table I) (Audu et al. 2014). In flax plants, seeds contain the highest amount of CP (21%) and EE (43.17%), and maximum CF (avg. 51.23%) and CC (avg. 33.38%) in fibre (Table I) (Ishag et al. 2019). Thermogravimetric analysis The TGA curves were used to determine the thermal behaviour such as weight loss and residual char level of material at a certain temperature. The thermal behaviour of untreated hemp and flax fibres is shown in Fig. 1. Fibres of all the genot ypea are lignocellulosic and show almost similar thermal degradation patterns. Thermal degradation profiles of the fibres are separated into three different stages. The first stage of degradation started at around 100°C and last up to 180°C. At this stage, about 10% mass loss occurs. Mass loss of fibres at around 100°C due to elimination or rapid evaporation of water during the initial stages of heating (Ouajai and Shanks, 2005). In addition to moisture, some fraction of waxes, pectin, lignin and hemicellulose degraded in this stage (Wielage et al. 1999). Decomposing of both the hemp and flax fibres takes place slowly up to about 250°C. Later the second decomposition started where the maximum mass loss occurred. Maximum decomposition took place between 250 and 350°C due to the depolymerization of cellulose and hemicellulose (Albano et al. 1999). It is obvious from the proximate analysis (Table I) that there is a difference in the chemical composition of the genotypes that affects the thermal stability. The thermal stability of the flax genotypes Chilmari and BD-10708 showed higher than the others. The third stage of decomposition begins at a temperature of about 350°C. At this stage, the fibre breaks down to form chars releasing water and carbon dioxide. With a further increase in temperature, the process of formation and digestion of chars takes place. The stable residual mass at 500°C temperature comes mostly from minerals and char residue (Gashti et al. 2013). Proximate analysis showed that hemp fibre had higher ash content on average than flax fibre (Table I). The TGA analysis also coincides with the proximate analysis showing a higher residual mass fraction at 500°C for hemp fibres. Conclusion The lower ash and ether extract and higher DM, CC and CF of these flax fibres make them (also) suitable for being used in the lightweight composite, textile, pulp and cellulose-based industries. The hemp fibre had higher ash which was reflected by a higher residue at 500°C in TGA analysis. High ash content in the hemp fibres will provide high thermal stability and could be used as reinforcement material for composite. Further investigations are needed to understand the viability of these flax fibres for different purposes. References Albano C, Gonzalez J, Ichazo M and Kaiser D (1999), Thermal stability of blends of polyolefins and sisal fiber, Polym Degrad Stab. 66(2): 179-190. . Alonso-Esteban JI, Pinela J, Ćirić A, Calhelha RC, Soković M, Ferreira IC, Barros L, Torija-Isasa E and de Cortes Sánchez-Mata M (2022), Chemical composition and biological activities of whole and dehulled hemp (Cannabis sativa L.) seeds, Food Chem. 374: 131754. Doi: 10.1016/j.foodchem.2021.131754 Audu BS, Ofojekwu PC, Ujah A and Ajima MNO (2014), Phytochemical, proximate composition, amino acid profile and characterization of Marijuana (Cannabis sativa L.), J Phytopharma. 3(1): 35-43. Baley C, Bourmaud A and Davies P (2021), Eighty years of composites reinforced by flax fibres: A historical review, Composites Part A: Appl Sci Manufac 144: 106333. Doi: 10.1016/j.compositesa.2021.106333 European Parliament and Council of the European Union, (2011), Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, amending Regulations (EC) No 1924/ 2006 and (EC) No 1925/2006 of the European Parliament and of the Council, and repealing Commission Directive 87/250/EEC, Council Directive 90/496/EEC, Commission Directive 1999/10/EC, Directive 2000/13/EC of the European Parliament and of the Council, Commission Directives 2002/67/EC and 2008/5/EC and Commission Regulation (EC) No 608/2004. Official Journal of the European Union, L 304: 18-63. Galasso I, Russo R, Mapelli S, Ponzoni E, Brambilla IM, Battelli G and Reggiani R (2016), Variability in seed traits in a collection of Cannabis sativa L. genotypes, Front Plant Sci. 7: 688. Doi: 10.3389/ fpls. 2016.00688 Gashti MP, Elahi A and Gashti MP (2013), UV radiation inducing succinic acid/silica–kaolinite network on cellulose fiber to improve the functionality, Compos B Eng. 48: 158-166 Girijappa YT, Rangappa SM, Parameswaranpillai J and Siengchin S (2019), Natural fibers as sustainable and renewable resource for development of eco-friendly composites: A comprehensive review, Front Mater 6: 226. Doi: 10.3389/fmats.2019.00226 Hashim S, Bakht T, Marwat KB and Jan A (2014), Medicinal properties, phytochemistry and pharmacology of Tribulus terrestris L. (Zygophyllaceae), Pak J Bot. 46(1): 399-404. . Ishag OAO, Khalid AA, Abdi A, Erwa IY, Omer AB and Nour AH (2019), Proximate composition, physicochemical properties and antioxidant activity of Flaxseed, Annl Res Rev Biol. 34(2): 1-10. Judd A (1995), Flaxseed in Human Nutrition. eds by S.C. Cunnane, L.U. Thompson. (AOCS Press, Champaign, IL) 1995, pp 1-10. Kabir AA, Moniruzzaman M, Gulshan Z, Rahman AM and Sarwar AKM Golam (2018), Biomass yield, chemical composition and in vitro gas production of different dhaincha (Sesbania spp.) Accessions from Bangladesh, Indian Anim Nutri. 35(4): 397-402. Doi: 10.5958/2231-6744.2018.00060.9 Lai PK and Roy J (2004), Antimicrobial and chemopreventive properties of herbs and spices, Curr Med Chem. 11(11): 1451-1460. Milburn W (1813), Oriental Commerce.Vol. 2 (Black, Parry & Co, London) 1813, pp 209-11. Misnon MI, Islam MM, Epaarachchi JA and Lau KT (2014), Potentiality of utilising natural textile materials for engineering composites applications, Mater Des. 59: 359-368. Doi: 10.1016/j.matdes.2014.03.022 Muir AD and Westcott ND (2003), Flax: the genus Linum. (CRC press) 2003. Mundaragi A, Devarajan T, Bhat S and Jeyabalan S (2017), Proximate analysis and mineral composition of potential minor fruits of Western Ghats of India. Scientific Papers. Series A. Agronomy, LX., pp 340-346. O’Malley LSS (1916), Bengal district gazetteers: Rajshahi. (Bengal Secretariat Book Depot, Calcutta) 1996, pp 134-144 O'Malley LSS (1908), Eastern Bengal District Gazetteers: Chittagong (Bengal Secretariat Book Depot, Calcutta) 1908. Ouajai S and Shanks RA (2005), Composition, structure and thermal degradation of hemp cellulose after chemical treatments, Polym Degrad Stab. 89(2): 327-335. Rahman AM, Nemoto K, Matsushima KI, Uddin SB and Sarwar AKM Golam (2022), A history of cannabis (Ganja) as an economic crop in Bangladesh from the late 18th century to 1989, Trop Agric Develop 66(1): 21-32. Doi: 10.9790/0837-2509041926 Roy S, Ali M, Amin MN, Jianguang S, Bhattacharya SK, Sen HS, Sur D, Lutfar LB, Rahman MS, Hassan DS (2010), Jute Basics, International Jute Study Group, Monipuri Para, Dhaka. Shuvo II (2020), Fibre attributes and mapping the cultivar influence of different industrial cellulosic crops (cotton, hemp, flax, and canola) on textile properties, Bioresour Bioprocess 7(51): 1-28. Doi: 10.1177/ 0040517519886636 Shuvo II, Rahman M, Vahora T, Morrison J, DuCharme S and Choo-Smith LPI (2020), Producing light-weight bast fibers from canola biomass for technical textiles, Tex Res J. 90(11-12): 1311-1325. Doi: 10.1186/ s40643-020-00339-1 Skoglund G, Nockert M and Holst B (2013), Viking and early Middle Ages northern Scandinavian textiles proven to be made with hemp, Sci Rep. 3(1): 1-6. Doi: 10.1038/srep02686 Waris Z, Iqbal Y, Arshad Hussain S, Khan AA, Ali A and Khan MW (2018), Proximate composition, phytochemical analysis and antioxidant capacity of Aloe vera, Cannabis sativa and Mentha longifolia, Pure Appl Biol. 7(3): 1122-1130. Doi: 10.19045/ bspab.2018.700131 Wielage B, Lampke T, Marx G, Nestler K and Starke D (1999), Thermogravimetric and differential scanning calorimetric analysis of natural fibres and polypropylene, Thermochimica Acta. 337(1-2): 169-177. 2016; Waris et al. 2018; Ishag et al. 2019; Alonso-Esteban et al. 2022). Although the physical properties of hemp and flax fibres are known to us (Girijappa et al. 2019), hitherto, no information on the proximate composition of fibres of Bangladeshi genotypes of these two important fibre-yielding crops is available. The constituent fibre properties influence application of textiles in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, as well as the apparel or clothing industry (Shuvo, 2020). We have, therefore, reported the proximate composition and thermogravimetric analysis data of 3 hemp and 6 flax genotypes here. Materials and methods The proximate analysis and thermogravimetric analysis (of fibres) of six flax genotypes and three hemp genotypes were carried out to understand their suitability in different applications. Hemp seeds were collected from different locations in Bangladesh (detailed collection information will be available upon request) and the genotypes are named accordingly, viz. Brammonbaria, Chittagang and Meherpur. The hemp plants were grown (in a confined area) at Botanical Garden, Department of Crop Botany, Bangladesh Agricultural University. Flax fibres were collected with the ribbon retting method (Roy et al. 2010) and sun-dried properly. The flax fibres of 6 genotypes, harvested from another experiment in the same year, were collected from the Laboratory of Plant Systematics of the same Department. The proximate composition analysis viz. dry matter (DM), crude protein (CP), crude fibre (CF), ash and ether extract (crude fat; EE), were accomplished at the Laboratory of Department of Animal Science, Bangladesh Agricultural University, Mymensingh following standard procedure (Kabir et al. 2018). The crude carbohydrate was calculated following Mundaragi et al. (2017). Crude Carbohydrate (%) = 100 – [moisture (%) + protein (%) + fibre (%) + fat (%) + ash (%)] The calorific value or the total energy value of fruits in kcal100–1 g was calculated with the help of the following equation (European Parliament and Council of the European Union, 2011). Energy value (kcal 100–1 g) = 4 × Protein + 9 × Fat + 4 × Carbohydrate + 2 × Fibre Genotype Dry matter (%) Ash (%) Crude Protein (%) Crude Fibre (%) Ether Extract (%) Crude Carbohydrate (%) Energy Value (kcal 100–1 g) Hemp Meherpur 96.9 17.7 7.94 29.10 18.30 23.86 350.1 Brammonbaria 97.1 14.8 8.65 26.51 12.35 34.79 337.93 Chittagang 97.0 12.5 9.02 29.27 20.90 25.31 383.96 Average 97±0.08 15±2.13 8.54±0.45 28.29±1.26 17.18±3.58 27.99±4.85 357.33±19.47 Flax Nila 96.0 2.3 3.64 49.21 2.60 38.25 289.38 Chilmari 96.2 1.7 3.27 52.21 3.91 35.11 293.13 China 96.5 3.8 3.62 51.73 3.42 33.93 284.44 BD-10708 96.8 1.8 5.24 47.28 9.70 32.78 333.94 Canada 96.7 1.8 3.98 55.32 4.50 31.1 291.46 BD-1903 96.3 2.0 3.27 51.60 10.30 29.13 325.5 Average 96.4±0.31 2.23±0.79 3.84±0.74 51.23±2.75 5.74±3.36 33.38±3.18 302.98±21.09 Table I. Proximate analysis of fibres of different hemp and flax genotypes Proximate composition and thermal properties of hemp and flax fibres 58(1) 202368 furniture, construction, packaging, and shipping pallets, etc. for their better physicochemical and physicomechanical properties (Girijappa et al. 2019). The quality and use of a natural fibre may vary due to inherent variabilities in its natural components such as fibrous nature, fibre morphology, cellulosic, and non-cellulosic content, and key properties such as fibrous structure, spinnability, strength, fineness, dyeability, and the ability to react with acid or alkali (Shuvo, 2020). Hemp (Cannabis sativa L.; Cannabaceae) and flax (Linum usit at issimum L.; Linaceae), two of the oldest cultivated fibre plants, fibres are singly or combined used for clothing and household textiles (Skoglund et al. 2013). Hemp has also various traditional uses in the Indian subcontinent such as fibre and roasted seeds eaten as a food. In Bangladesh, the hemp plant was cultivated for manufacturing three narcotic products called Ganja, Charas and Bhang (O’Malley, 1916); there are disagreements over the use of hemp fibres. According to O’Malley, hemp was cultivated on 8,000 acres (approx. 3,250 ha) of land of Sitakund on the banks of the Sangu River and in the southeast of Satkania on the banks of Tankabati for producing hemp fibre (O’Malley, 1908). Milburn initially mentioned that hemp has been cultivated in Bengal from time immemorial for intoxication (Milburn, 1813); but is never used by natives for cordage or cloth, as in Europe. However, he also pointed out later that when hemp is intended for cordage, the natives sow it very thin and afterwards transplant the young plants, placing them at a considerable distance from each other, often 2.75 or 3.0 m. The history of commercial hemp cultivation in Bangladesh has been discussed (Rahman et al. 2022). Hemp fibres are used in rope, textiles, garden mulch, an assortment of building materials and animal beddings, to fabricate different composites, and processed to form yarn or bundles (Girijappa et al. 2019). The history of linen production and use dates back to 12000 BC (Vedic age) to 1500 CE (Medieval period) in the Indian subcontinent, including India, Pakistan and Bangladesh <https:// agropedia.i itk.ac.in/ content/history- linen- indian-subcontinent>. Edible flaxseed dominated India’s production rather than fibre flax; because other fibre species, such as hemp, were already in wide use (Judd, 1995). Flax fibres are used in furniture materials, textiles bed sheets, linen, interior decoration accessories, composite reinforcement, etc. (Girijappa et al. 2019; Baley, 2021). The nutritional aspects of both hemp and flax seeds and different plant parts were reported in different publications (Muir and Westcott, 2003; Audu et al. 2014; Galasso et al. Thermogravimetric analysis (TGA) was performed by a thermal analyzer of SII TG/DTA 6300. Thermal analysis was carried out in the temperature range of 30–500°C with a programmed heating rate of 20°C min–1. The inertness of the heating chamber was maintained with continuous nitrogen gas flow at 100 ml min–1. The test was performed with a 5 to 8 mg ground sample in the platinum crucible. Results and discussion Proximate analysis Distinct differences in all the proximate components were observed between fibre of hemp and flax genotypes except the DM content. The results revealed a close similarity in the DM content of hemp and flax fibres which varied from 96% to 97.1% (Table I). High DM content in fibre cells indicates that these are rich in structural components – carbohydrates, protein, fats, minerals, etc. except water. The density of hemp and flax fibres was the same or very similar and low (1.4–1.5 g cm–3) which could be a great choice for light-weight composite structures (Misnon, 2014). Low-density fibre has enormous implications in technical textile industries, especially in aerospace and automotive applications for reducing fuel consumption and related fuel costs (Shuvo et al. 2020). A careful selection of cultivars (/genotypes) would allow for the optimizing utility of this fibre feature (Shuvo, 2020). Ash content was analyzed in the range of 1.7% to 17.7% and a significant difference was observed between hemp (12.5–17.7%) and flax (1.7–3.8%) genotypes. The maximum ash was found in hemp genotype Meherpur and the minimum in flax genotype Chilmari. Ash is the residue left after all the moisture and organic matter has been removed at high temperatures. The high ash content of these fibres is a measure of mineral richness (Lai and Roy, 2004). The maximum quantity of CP, EE and energy value was found in hemp genotypes and minimum in flax genotypes. Fibres of two flax genotypes, viz. BD-10708 and BD-1903, contained an exceptionally higher amount of ether extract compared to others (Table I). In living organisms, fat is the usually stored form of energy. They are the main structural element of phospholipids and sterols (Hashim et al. 2014). The CF and crude carbohydrate (CC) contents showed the maximum value for flax genotype Canada (55.32%) and Nila (38.25%), respectively and a minimum for hemp genotype Brammonbaria (26.51%) and Meherpur (23.86%). The energy value of hemp genotypes was higher and ranged from 337.93 to 383.96 kcal 100–1 g (Table I). This augmented energy value is due to their greater fat content compared with flax genotypes (Ishag et al. 2019). Among the different plant parts of hemp, the leaf possessed the maximum amount (23.78%) of CP (Audu et al. 2014). On the other hand, fibre contains the highest amount of CF (28.29%) and ash (12%); EE (%) of the leaf was identical to that of fibre except in one genotype Brammonbaria (Table I) (Audu et al. 2014). In flax plants, seeds contain the highest amount of CP (21%) and EE (43.17%), and maximum CF (avg. 51.23%) and CC (avg. 33.38%) in fibre (Table I) (Ishag et al. 2019). Thermogravimetric analysis The TGA curves were used to determine the thermal behaviour such as weight loss and residual char level of material at a certain temperature. The thermal behaviour of untreated hemp and flax fibres is shown in Fig. 1. Fibres of all the genot ypea are lignocellulosic and show almost similar thermal degradation patterns. Thermal degradation profiles of the fibres are separated into three different stages. The first stage of degradation started at around 100°C and last up to 180°C. At this stage, about 10% mass loss occurs. Mass loss of fibres at around 100°C due to elimination or rapid evaporation of water during the initial stages of heating (Ouajai and Shanks, 2005). In addition to moisture, some fraction of waxes, pectin, lignin and hemicellulose degraded in this stage (Wielage et al. 1999). Decomposing of both the hemp and flax fibres takes place slowly up to about 250°C. Later the second decomposition started where the maximum mass loss occurred. Maximum decomposition took place between 250 and 350°C due to the depolymerization of cellulose and hemicellulose (Albano et al. 1999). It is obvious from the proximate analysis (Table I) that there is a difference in the chemical composition of the genotypes that affects the thermal stability. The thermal stability of the flax genotypes Chilmari and BD-10708 showed higher than the others. The third stage of decomposition begins at a temperature of about 350°C. At this stage, the fibre breaks down to form chars releasing water and carbon dioxide. With a further increase in temperature, the process of formation and digestion of chars takes place. The stable residual mass at 500°C temperature comes mostly from minerals and char residue (Gashti et al. 2013). Proximate analysis showed that hemp fibre had higher ash content on average than flax fibre (Table I). The TGA analysis also coincides with the proximate analysis showing a higher residual mass fraction at 500°C for hemp fibres. Conclusion The lower ash and ether extract and higher DM, CC and CF of these flax fibres make them (also) suitable for being used in the lightweight composite, textile, pulp and cellulose-based industries. The hemp fibre had higher ash which was reflected by a higher residue at 500°C in TGA analysis. High ash content in the hemp fibres will provide high thermal stability and could be used as reinforcement material for composite. Further investigations are needed to understand the viability of these flax fibres for different purposes. References Albano C, Gonzalez J, Ichazo M and Kaiser D (1999), Thermal stability of blends of polyolefins and sisal fiber, Polym Degrad Stab. 66(2): 179-190. . Alonso-Esteban JI, Pinela J, Ćirić A, Calhelha RC, Soković M, Ferreira IC, Barros L, Torija-Isasa E and de Cortes Sánchez-Mata M (2022), Chemical composition and biological activities of whole and dehulled hemp (Cannabis sativa L.) seeds, Food Chem. 374: 131754. Doi: 10.1016/j.foodchem.2021.131754 Audu BS, Ofojekwu PC, Ujah A and Ajima MNO (2014), Phytochemical, proximate composition, amino acid profile and characterization of Marijuana (Cannabis sativa L.), J Phytopharma. 3(1): 35-43. Baley C, Bourmaud A and Davies P (2021), Eighty years of composites reinforced by flax fibres: A historical review, Composites Part A: Appl Sci Manufac 144: 106333. Doi: 10.1016/j.compositesa.2021.106333 European Parliament and Council of the European Union, (2011), Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, amending Regulations (EC) No 1924/ 2006 and (EC) No 1925/2006 of the European Parliament and of the Council, and repealing Commission Directive 87/250/EEC, Council Directive 90/496/EEC, Commission Directive 1999/10/EC, Directive 2000/13/EC of the European Parliament and of the Council, Commission Directives 2002/67/EC and 2008/5/EC and Commission Regulation (EC) No 608/2004. Official Journal of the European Union, L 304: 18-63. Galasso I, Russo R, Mapelli S, Ponzoni E, Brambilla IM, Battelli G and Reggiani R (2016), Variability in seed traits in a collection of Cannabis sativa L. genotypes, Front Plant Sci. 7: 688. Doi: 10.3389/ fpls. 2016.00688 Gashti MP, Elahi A and Gashti MP (2013), UV radiation inducing succinic acid/silica–kaolinite network on cellulose fiber to improve the functionality, Compos B Eng. 48: 158-166 Girijappa YT, Rangappa SM, Parameswaranpillai J and Siengchin S (2019), Natural fibers as sustainable and renewable resource for development of eco-friendly composites: A comprehensive review, Front Mater 6: 226. Doi: 10.3389/fmats.2019.00226 Hashim S, Bakht T, Marwat KB and Jan A (2014), Medicinal properties, phytochemistry and pharmacology of Tribulus terrestris L. (Zygophyllaceae), Pak J Bot. 46(1): 399-404. . Ishag OAO, Khalid AA, Abdi A, Erwa IY, Omer AB and Nour AH (2019), Proximate composition, physicochemical properties and antioxidant activity of Flaxseed, Annl Res Rev Biol. 34(2): 1-10. Judd A (1995), Flaxseed in Human Nutrition. eds by S.C. Cunnane, L.U. Thompson. (AOCS Press, Champaign, IL) 1995, pp 1-10. Kabir AA, Moniruzzaman M, Gulshan Z, Rahman AM and Sarwar AKM Golam (2018), Biomass yield, chemical composition and in vitro gas production of different dhaincha (Sesbania spp.) Accessions from Bangladesh, Indian Anim Nutri. 35(4): 397-402. Doi: 10.5958/2231-6744.2018.00060.9 Lai PK and Roy J (2004), Antimicrobial and chemopreventive properties of herbs and spices, Curr Med Chem. 11(11): 1451-1460. Milburn W (1813), Oriental Commerce.Vol. 2 (Black, Parry & Co, London) 1813, pp 209-11. Misnon MI, Islam MM, Epaarachchi JA and Lau KT (2014), Potentiality of utilising natural textile materials for engineering composites applications, Mater Des. 59: 359-368. Doi: 10.1016/j.matdes.2014.03.022 Muir AD and Westcott ND (2003), Flax: the genus Linum. (CRC press) 2003. Mundaragi A, Devarajan T, Bhat S and Jeyabalan S (2017), Proximate analysis and mineral composition of potential minor fruits of Western Ghats of India. Scientific Papers. Series A. Agronomy, LX., pp 340-346. O’Malley LSS (1916), Bengal district gazetteers: Rajshahi. (Bengal Secretariat Book Depot, Calcutta) 1996, pp 134-144 O'Malley LSS (1908), Eastern Bengal District Gazetteers: Chittagong (Bengal Secretariat Book Depot, Calcutta) 1908. Ouajai S and Shanks RA (2005), Composition, structure and thermal degradation of hemp cellulose after chemical treatments, Polym Degrad Stab. 89(2): 327-335. Rahman AM, Nemoto K, Matsushima KI, Uddin SB and Sarwar AKM Golam (2022), A history of cannabis (Ganja) as an economic crop in Bangladesh from the late 18th century to 1989, Trop Agric Develop 66(1): 21-32. Doi: 10.9790/0837-2509041926 Roy S, Ali M, Amin MN, Jianguang S, Bhattacharya SK, Sen HS, Sur D, Lutfar LB, Rahman MS, Hassan DS (2010), Jute Basics, International Jute Study Group, Monipuri Para, Dhaka. Shuvo II (2020), Fibre attributes and mapping the cultivar influence of different industrial cellulosic crops (cotton, hemp, flax, and canola) on textile properties, Bioresour Bioprocess 7(51): 1-28. Doi: 10.1177/ 0040517519886636 Shuvo II, Rahman M, Vahora T, Morrison J, DuCharme S and Choo-Smith LPI (2020), Producing light-weight bast fibers from canola biomass for technical textiles, Tex Res J. 90(11-12): 1311-1325. Doi: 10.1186/ s40643-020-00339-1 Skoglund G, Nockert M and Holst B (2013), Viking and early Middle Ages northern Scandinavian textiles proven to be made with hemp, Sci Rep. 3(1): 1-6. Doi: 10.1038/srep02686 Waris Z, Iqbal Y, Arshad Hussain S, Khan AA, Ali A and Khan MW (2018), Proximate composition, phytochemical analysis and antioxidant capacity of Aloe vera, Cannabis sativa and Mentha longifolia, Pure Appl Biol. 7(3): 1122-1130. Doi: 10.19045/ bspab.2018.700131 Wielage B, Lampke T, Marx G, Nestler K and Starke D (1999), Thermogravimetric and differential scanning calorimetric analysis of natural fibres and polypropylene, Thermochimica Acta. 337(1-2): 169-177. 2016; Waris et al. 2018; Ishag et al. 2019; Alonso-Esteban et al. 2022). Although the physical properties of hemp and flax fibres are known to us (Girijappa et al. 2019), hitherto, no information on the proximate composition of fibres of Bangladeshi genotypes of these two important fibre-yielding crops is available. The constituent fibre properties influence application of textiles in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, as well as the apparel or clothing industry (Shuvo, 2020). We have, therefore, reported the proximate composition and thermogravimetric analysis data of 3 hemp and 6 flax genotypes here. Materials and methods The proximate analysis and thermogravimetric analysis (of fibres) of six flax genotypes and three hemp genotypes were carried out to understand their suitability in different applications. Hemp seeds were collected from different locations in Bangladesh (detailed collection information will be available upon request) and the genotypes are named accordingly, viz. Brammonbaria, Chittagang and Meherpur. The hemp plants were grown (in a confined area) at Botanical Garden, Department of Crop Botany, Bangladesh Agricultural University. Flax fibres were collected with the ribbon retting method (Roy et al. 2010) and sun-dried properly. The flax fibres of 6 genotypes, harvested from another experiment in the same year, were collected from the Laboratory of Plant Systematics of the same Department. The proximate composition analysis viz. dry matter (DM), crude protein (CP), crude fibre (CF), ash and ether extract (crude fat; EE), were accomplished at the Laboratory of Department of Animal Science, Bangladesh Agricultural University, Mymensingh following standard procedure (Kabir et al. 2018). The crude carbohydrate was calculated following Mundaragi et al. (2017). Crude Carbohydrate (%) = 100 – [moisture (%) + protein (%) + fibre (%) + fat (%) + ash (%)] The calorific value or the total energy value of fruits in kcal100–1 g was calculated with the help of the following equation (European Parliament and Council of the European Union, 2011). Energy value (kcal 100–1 g) = 4 × Protein + 9 × Fat + 4 × Carbohydrate + 2 × Fibre Fig. 1. Thermogravimetric analysis curves of fibres of different hemp and flax genotypes Rahman, Rahman, Nemoto and Sarwar 69 furniture, construction, packaging, and shipping pallets, etc. for their better physicochemical and physicomechanical properties (Girijappa et al. 2019). The quality and use of a natural fibre may vary due to inherent variabilities in its natural components such as fibrous nature, fibre morphology, cellulosic, and non-cellulosic content, and key properties such as fibrous structure, spinnability, strength, fineness, dyeability, and the ability to react with acid or alkali (Shuvo, 2020). Hemp (Cannabis sativa L.; Cannabaceae) and flax (Linum usit at issimum L.; Linaceae), two of the oldest cultivated fibre plants, fibres are singly or combined used for clothing and household textiles (Skoglund et al. 2013). Hemp has also various traditional uses in the Indian subcontinent such as fibre and roasted seeds eaten as a food. In Bangladesh, the hemp plant was cultivated for manufacturing three narcotic products called Ganja, Charas and Bhang (O’Malley, 1916); there are disagreements over the use of hemp fibres. According to O’Malley, hemp was cultivated on 8,000 acres (approx. 3,250 ha) of land of Sitakund on the banks of the Sangu River and in the southeast of Satkania on the banks of Tankabati for producing hemp fibre (O’Malley, 1908). Milburn initially mentioned that hemp has been cultivated in Bengal from time immemorial for intoxication (Milburn, 1813); but is never used by natives for cordage or cloth, as in Europe. However, he also pointed out later that when hemp is intended for cordage, the natives sow it very thin and afterwards transplant the young plants, placing them at a considerable distance from each other, often 2.75 or 3.0 m. The history of commercial hemp cultivation in Bangladesh has been discussed (Rahman et al. 2022). Hemp fibres are used in rope, textiles, garden mulch, an assortment of building materials and animal beddings, to fabricate different composites, and processed to form yarn or bundles (Girijappa et al. 2019). The history of linen production and use dates back to 12000 BC (Vedic age) to 1500 CE (Medieval period) in the Indian subcontinent, including India, Pakistan and Bangladesh <https:// agropedia.i itk.ac.in/ content/history- linen- indian-subcontinent>. Edible flaxseed dominated India’s production rather than fibre flax; because other fibre species, such as hemp, were already in wide use (Judd, 1995). Flax fibres are used in furniture materials, textiles bed sheets, linen, interior decoration accessories, composite reinforcement, etc. (Girijappa et al. 2019; Baley, 2021). The nutritional aspects of both hemp and flax seeds and different plant parts were reported in different publications (Muir and Westcott, 2003; Audu et al. 2014; Galasso et al. Thermogravimetric analysis (TGA) was performed by a thermal analyzer of SII TG/DTA 6300. Thermal analysis was carried out in the temperature range of 30–500°C with a programmed heating rate of 20°C min–1. The inertness of the heating chamber was maintained with continuous nitrogen gas flow at 100 ml min–1. The test was performed with a 5 to 8 mg ground sample in the platinum crucible. Results and discussion Proximate analysis Distinct differences in all the proximate components were observed between fibre of hemp and flax genotypes except the DM content. The results revealed a close similarity in the DM content of hemp and flax fibres which varied from 96% to 97.1% (Table I). High DM content in fibre cells indicates that these are rich in structural components – carbohydrates, protein, fats, minerals, etc. except water. The density of hemp and flax fibres was the same or very similar and low (1.4–1.5 g cm–3) which could be a great choice for light-weight composite structures (Misnon, 2014). Low-density fibre has enormous implications in technical textile industries, especially in aerospace and automotive applications for reducing fuel consumption and related fuel costs (Shuvo et al. 2020). A careful selection of cultivars (/genotypes) would allow for the optimizing utility of this fibre feature (Shuvo, 2020). Ash content was analyzed in the range of 1.7% to 17.7% and a significant difference was observed between hemp (12.5–17.7%) and flax (1.7–3.8%) genotypes. The maximum ash was found in hemp genotype Meherpur and the minimum in flax genotype Chilmari. Ash is the residue left after all the moisture and organic matter has been removed at high temperatures. The high ash content of these fibres is a measure of mineral richness (Lai and Roy, 2004). The maximum quantity of CP, EE and energy value was found in hemp genotypes and minimum in flax genotypes. Fibres of two flax genotypes, viz. BD-10708 and BD-1903, contained an exceptionally higher amount of ether extract compared to others (Table I). In living organisms, fat is the usually stored form of energy. They are the main structural element of phospholipids and sterols (Hashim et al. 2014). The CF and crude carbohydrate (CC) contents showed the maximum value for flax genotype Canada (55.32%) and Nila (38.25%), respectively and a minimum for hemp genotype Brammonbaria (26.51%) and Meherpur (23.86%). The energy value of hemp genotypes was higher and ranged from 337.93 to 383.96 kcal 100–1 g (Table I). This augmented energy value is due to their greater fat content compared with flax genotypes (Ishag et al. 2019). Among the different plant parts of hemp, the leaf possessed the maximum amount (23.78%) of CP (Audu et al. 2014). On the other hand, fibre contains the highest amount of CF (28.29%) and ash (12%); EE (%) of the leaf was identical to that of fibre except in one genotype Brammonbaria (Table I) (Audu et al. 2014). In flax plants, seeds contain the highest amount of CP (21%) and EE (43.17%), and maximum CF (avg. 51.23%) and CC (avg. 33.38%) in fibre (Table I) (Ishag et al. 2019). Thermogravimetric analysis The TGA curves were used to determine the thermal behaviour such as weight loss and residual char level of material at a certain temperature. The thermal behaviour of untreated hemp and flax fibres is shown in Fig. 1. Fibres of all the genot ypea are lignocellulosic and show almost similar thermal degradation patterns. Thermal degradation profiles of the fibres are separated into three different stages. The first stage of degradation started at around 100°C and last up to 180°C. At this stage, about 10% mass loss occurs. Mass loss of fibres at around 100°C due to elimination or rapid evaporation of water during the initial stages of heating (Ouajai and Shanks, 2005). In addition to moisture, some fraction of waxes, pectin, lignin and hemicellulose degraded in this stage (Wielage et al. 1999). Decomposing of both the hemp and flax fibres takes place slowly up to about 250°C. Later the second decomposition started where the maximum mass loss occurred. Maximum decomposition took place between 250 and 350°C due to the depolymerization of cellulose and hemicellulose (Albano et al. 1999). It is obvious from the proximate analysis (Table I) that there is a difference in the chemical composition of the genotypes that affects the thermal stability. The thermal stability of the flax genotypes Chilmari and BD-10708 showed higher than the others. The third stage of decomposition begins at a temperature of about 350°C. At this stage, the fibre breaks down to form chars releasing water and carbon dioxide. With a further increase in temperature, the process of formation and digestion of chars takes place. The stable residual mass at 500°C temperature comes mostly from minerals and char residue (Gashti et al. 2013). Proximate analysis showed that hemp fibre had higher ash content on average than flax fibre (Table I). The TGA analysis also coincides with the proximate analysis showing a higher residual mass fraction at 500°C for hemp fibres. Conclusion The lower ash and ether extract and higher DM, CC and CF of these flax fibres make them (also) suitable for being used in the lightweight composite, textile, pulp and cellulose-based industries. The hemp fibre had higher ash which was reflected by a higher residue at 500°C in TGA analysis. High ash content in the hemp fibres will provide high thermal stability and could be used as reinforcement material for composite. Further investigations are needed to understand the viability of these flax fibres for different purposes. References Albano C, Gonzalez J, Ichazo M and Kaiser D (1999), Thermal stability of blends of polyolefins and sisal fiber, Polym Degrad Stab. 66(2): 179-190. . Alonso-Esteban JI, Pinela J, Ćirić A, Calhelha RC, Soković M, Ferreira IC, Barros L, Torija-Isasa E and de Cortes Sánchez-Mata M (2022), Chemical composition and biological activities of whole and dehulled hemp (Cannabis sativa L.) seeds, Food Chem. 374: 131754. Doi: 10.1016/j.foodchem.2021.131754 Audu BS, Ofojekwu PC, Ujah A and Ajima MNO (2014), Phytochemical, proximate composition, amino acid profile and characterization of Marijuana (Cannabis sativa L.), J Phytopharma. 3(1): 35-43. Baley C, Bourmaud A and Davies P (2021), Eighty years of composites reinforced by flax fibres: A historical review, Composites Part A: Appl Sci Manufac 144: 106333. Doi: 10.1016/j.compositesa.2021.106333 European Parliament and Council of the European Union, (2011), Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, amending Regulations (EC) No 1924/ 2006 and (EC) No 1925/2006 of the European Parliament and of the Council, and repealing Commission Directive 87/250/EEC, Council Directive 90/496/EEC, Commission Directive 1999/10/EC, Directive 2000/13/EC of the European Parliament and of the Council, Commission Directives 2002/67/EC and 2008/5/EC and Commission Regulation (EC) No 608/2004. Official Journal of the European Union, L 304: 18-63. Galasso I, Russo R, Mapelli S, Ponzoni E, Brambilla IM, Battelli G and Reggiani R (2016), Variability in seed traits in a collection of Cannabis sativa L. genotypes, Front Plant Sci. 7: 688. Doi: 10.3389/ fpls. 2016.00688 Gashti MP, Elahi A and Gashti MP (2013), UV radiation inducing succinic acid/silica–kaolinite network on cellulose fiber to improve the functionality, Compos B Eng. 48: 158-166 Girijappa YT, Rangappa SM, Parameswaranpillai J and Siengchin S (2019), Natural fibers as sustainable and renewable resource for development of eco-friendly composites: A comprehensive review, Front Mater 6: 226. Doi: 10.3389/fmats.2019.00226 Hashim S, Bakht T, Marwat KB and Jan A (2014), Medicinal properties, phytochemistry and pharmacology of Tribulus terrestris L. (Zygophyllaceae), Pak J Bot. 46(1): 399-404. . Ishag OAO, Khalid AA, Abdi A, Erwa IY, Omer AB and Nour AH (2019), Proximate composition, physicochemical properties and antioxidant activity of Flaxseed, Annl Res Rev Biol. 34(2): 1-10. Judd A (1995), Flaxseed in Human Nutrition. eds by S.C. Cunnane, L.U. Thompson. (AOCS Press, Champaign, IL) 1995, pp 1-10. Kabir AA, Moniruzzaman M, Gulshan Z, Rahman AM and Sarwar AKM Golam (2018), Biomass yield, chemical composition and in vitro gas production of different dhaincha (Sesbania spp.) Accessions from Bangladesh, Indian Anim Nutri. 35(4): 397-402. Doi: 10.5958/2231-6744.2018.00060.9 Lai PK and Roy J (2004), Antimicrobial and chemopreventive properties of herbs and spices, Curr Med Chem. 11(11): 1451-1460. Milburn W (1813), Oriental Commerce.Vol. 2 (Black, Parry & Co, London) 1813, pp 209-11. Misnon MI, Islam MM, Epaarachchi JA and Lau KT (2014), Potentiality of utilising natural textile materials for engineering composites applications, Mater Des. 59: 359-368. Doi: 10.1016/j.matdes.2014.03.022 Muir AD and Westcott ND (2003), Flax: the genus Linum. (CRC press) 2003. Mundaragi A, Devarajan T, Bhat S and Jeyabalan S (2017), Proximate analysis and mineral composition of potential minor fruits of Western Ghats of India. Scientific Papers. Series A. Agronomy, LX., pp 340-346. O’Malley LSS (1916), Bengal district gazetteers: Rajshahi. (Bengal Secretariat Book Depot, Calcutta) 1996, pp 134-144 O'Malley LSS (1908), Eastern Bengal District Gazetteers: Chittagong (Bengal Secretariat Book Depot, Calcutta) 1908. Ouajai S and Shanks RA (2005), Composition, structure and thermal degradation of hemp cellulose after chemical treatments, Polym Degrad Stab. 89(2): 327-335. Rahman AM, Nemoto K, Matsushima KI, Uddin SB and Sarwar AKM Golam (2022), A history of cannabis (Ganja) as an economic crop in Bangladesh from the late 18th century to 1989, Trop Agric Develop 66(1): 21-32. Doi: 10.9790/0837-2509041926 Roy S, Ali M, Amin MN, Jianguang S, Bhattacharya SK, Sen HS, Sur D, Lutfar LB, Rahman MS, Hassan DS (2010), Jute Basics, International Jute Study Group, Monipuri Para, Dhaka. Shuvo II (2020), Fibre attributes and mapping the cultivar influence of different industrial cellulosic crops (cotton, hemp, flax, and canola) on textile properties, Bioresour Bioprocess 7(51): 1-28. Doi: 10.1177/ 0040517519886636 Shuvo II, Rahman M, Vahora T, Morrison J, DuCharme S and Choo-Smith LPI (2020), Producing light-weight bast fibers from canola biomass for technical textiles, Tex Res J. 90(11-12): 1311-1325. Doi: 10.1186/ s40643-020-00339-1 Skoglund G, Nockert M and Holst B (2013), Viking and early Middle Ages northern Scandinavian textiles proven to be made with hemp, Sci Rep. 3(1): 1-6. Doi: 10.1038/srep02686 Waris Z, Iqbal Y, Arshad Hussain S, Khan AA, Ali A and Khan MW (2018), Proximate composition, phytochemical analysis and antioxidant capacity of Aloe vera, Cannabis sativa and Mentha longifolia, Pure Appl Biol. 7(3): 1122-1130. Doi: 10.19045/ bspab.2018.700131 Wielage B, Lampke T, Marx G, Nestler K and Starke D (1999), Thermogravimetric and differential scanning calorimetric analysis of natural fibres and polypropylene, Thermochimica Acta. 337(1-2): 169-177. 2016; Waris et al. 2018; Ishag et al. 2019; Alonso-Esteban et al. 2022). Although the physical properties of hemp and flax fibres are known to us (Girijappa et al. 2019), hitherto, no information on the proximate composition of fibres of Bangladeshi genotypes of these two important fibre-yielding crops is available. The constituent fibre properties influence application of textiles in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, as well as the apparel or clothing industry (Shuvo, 2020). We have, therefore, reported the proximate composition and thermogravimetric analysis data of 3 hemp and 6 flax genotypes here. Materials and methods The proximate analysis and thermogravimetric analysis (of fibres) of six flax genotypes and three hemp genotypes were carried out to understand their suitability in different applications. Hemp seeds were collected from different locations in Bangladesh (detailed collection information will be available upon request) and the genotypes are named accordingly, viz. Brammonbaria, Chittagang and Meherpur. The hemp plants were grown (in a confined area) at Botanical Garden, Department of Crop Botany, Bangladesh Agricultural University. Flax fibres were collected with the ribbon retting method (Roy et al. 2010) and sun-dried properly. The flax fibres of 6 genotypes, harvested from another experiment in the same year, were collected from the Laboratory of Plant Systematics of the same Department. The proximate composition analysis viz. dry matter (DM), crude protein (CP), crude fibre (CF), ash and ether extract (crude fat; EE), were accomplished at the Laboratory of Department of Animal Science, Bangladesh Agricultural University, Mymensingh following standard procedure (Kabir et al. 2018). The crude carbohydrate was calculated following Mundaragi et al. (2017). Crude Carbohydrate (%) = 100 – [moisture (%) + protein (%) + fibre (%) + fat (%) + ash (%)] The calorific value or the total energy value of fruits in kcal100–1 g was calculated with the help of the following equation (European Parliament and Council of the European Union, 2011). Energy value (kcal 100–1 g) = 4 × Protein + 9 × Fat + 4 × Carbohydrate + 2 × Fibre Proximate composition and thermal properties of hemp and flax fibres 58(1) 202370 furniture, construction, packaging, and shipping pallets, etc. for their better physicochemical and physicomechanical properties (Girijappa et al. 2019). The quality and use of a natural fibre may vary due to inherent variabilities in its natural components such as fibrous nature, fibre morphology, cellulosic, and non-cellulosic content, and key properties such as fibrous structure, spinnability, strength, fineness, dyeability, and the ability to react with acid or alkali (Shuvo, 2020). Hemp (Cannabis sativa L.; Cannabaceae) and flax (Linum usit at issimum L.; Linaceae), two of the oldest cultivated fibre plants, fibres are singly or combined used for clothing and household textiles (Skoglund et al. 2013). Hemp has also various traditional uses in the Indian subcontinent such as fibre and roasted seeds eaten as a food. In Bangladesh, the hemp plant was cultivated for manufacturing three narcotic products called Ganja, Charas and Bhang (O’Malley, 1916); there are disagreements over the use of hemp fibres. According to O’Malley, hemp was cultivated on 8,000 acres (approx. 3,250 ha) of land of Sitakund on the banks of the Sangu River and in the southeast of Satkania on the banks of Tankabati for producing hemp fibre (O’Malley, 1908). Milburn initially mentioned that hemp has been cultivated in Bengal from time immemorial for intoxication (Milburn, 1813); but is never used by natives for cordage or cloth, as in Europe. However, he also pointed out later that when hemp is intended for cordage, the natives sow it very thin and afterwards transplant the young plants, placing them at a considerable distance from each other, often 2.75 or 3.0 m. The history of commercial hemp cultivation in Bangladesh has been discussed (Rahman et al. 2022). Hemp fibres are used in rope, textiles, garden mulch, an assortment of building materials and animal beddings, to fabricate different composites, and processed to form yarn or bundles (Girijappa et al. 2019). The history of linen production and use dates back to 12000 BC (Vedic age) to 1500 CE (Medieval period) in the Indian subcontinent, including India, Pakistan and Bangladesh <https:// agropedia.i itk.ac.in/ content/history- linen- indian-subcontinent>. Edible flaxseed dominated India’s production rather than fibre flax; because other fibre species, such as hemp, were already in wide use (Judd, 1995). Flax fibres are used in furniture materials, textiles bed sheets, linen, interior decoration accessories, composite reinforcement, etc. (Girijappa et al. 2019; Baley, 2021). The nutritional aspects of both hemp and flax seeds and different plant parts were reported in different publications (Muir and Westcott, 2003; Audu et al. 2014; Galasso et al. Thermogravimetric analysis (TGA) was performed by a thermal analyzer of SII TG/DTA 6300. Thermal analysis was carried out in the temperature range of 30–500°C with a programmed heating rate of 20°C min–1. The inertness of the heating chamber was maintained with continuous nitrogen gas flow at 100 ml min–1. The test was performed with a 5 to 8 mg ground sample in the platinum crucible. Results and discussion Proximate analysis Distinct differences in all the proximate components were observed between fibre of hemp and flax genotypes except the DM content. The results revealed a close similarity in the DM content of hemp and flax fibres which varied from 96% to 97.1% (Table I). High DM content in fibre cells indicates that these are rich in structural components – carbohydrates, protein, fats, minerals, etc. except water. The density of hemp and flax fibres was the same or very similar and low (1.4–1.5 g cm–3) which could be a great choice for light-weight composite structures (Misnon, 2014). Low-density fibre has enormous implications in technical textile industries, especially in aerospace and automotive applications for reducing fuel consumption and related fuel costs (Shuvo et al. 2020). A careful selection of cultivars (/genotypes) would allow for the optimizing utility of this fibre feature (Shuvo, 2020). Ash content was analyzed in the range of 1.7% to 17.7% and a significant difference was observed between hemp (12.5–17.7%) and flax (1.7–3.8%) genotypes. The maximum ash was found in hemp genotype Meherpur and the minimum in flax genotype Chilmari. Ash is the residue left after all the moisture and organic matter has been removed at high temperatures. The high ash content of these fibres is a measure of mineral richness (Lai and Roy, 2004). The maximum quantity of CP, EE and energy value was found in hemp genotypes and minimum in flax genotypes. Fibres of two flax genotypes, viz. BD-10708 and BD-1903, contained an exceptionally higher amount of ether extract compared to others (Table I). In living organisms, fat is the usually stored form of energy. They are the main structural element of phospholipids and sterols (Hashim et al. 2014). The CF and crude carbohydrate (CC) contents showed the maximum value for flax genotype Canada (55.32%) and Nila (38.25%), respectively and a minimum for hemp genotype Brammonbaria (26.51%) and Meherpur (23.86%). The energy value of hemp genotypes was higher and ranged from 337.93 to 383.96 kcal 100–1 g (Table I). This augmented energy value is due to their greater fat content compared with flax genotypes (Ishag et al. 2019). Among the different plant parts of hemp, the leaf possessed the maximum amount (23.78%) of CP (Audu et al. 2014). On the other hand, fibre contains the highest amount of CF (28.29%) and ash (12%); EE (%) of the leaf was identical to that of fibre except in one genotype Brammonbaria (Table I) (Audu et al. 2014). In flax plants, seeds contain the highest amount of CP (21%) and EE (43.17%), and maximum CF (avg. 51.23%) and CC (avg. 33.38%) in fibre (Table I) (Ishag et al. 2019). Thermogravimetric analysis The TGA curves were used to determine the thermal behaviour such as weight loss and residual char level of material at a certain temperature. The thermal behaviour of untreated hemp and flax fibres is shown in Fig. 1. Fibres of all the genot ypea are lignocellulosic and show almost similar thermal degradation patterns. Thermal degradation profiles of the fibres are separated into three different stages. The first stage of degradation started at around 100°C and last up to 180°C. At this stage, about 10% mass loss occurs. Mass loss of fibres at around 100°C due to elimination or rapid evaporation of water during the initial stages of heating (Ouajai and Shanks, 2005). In addition to moisture, some fraction of waxes, pectin, lignin and hemicellulose degraded in this stage (Wielage et al. 1999). Decomposing of both the hemp and flax fibres takes place slowly up to about 250°C. Later the second decomposition started where the maximum mass loss occurred. Maximum decomposition took place between 250 and 350°C due to the depolymerization of cellulose and hemicellulose (Albano et al. 1999). It is obvious from the proximate analysis (Table I) that there is a difference in the chemical composition of the genotypes that affects the thermal stability. The thermal stability of the flax genotypes Chilmari and BD-10708 showed higher than the others. The third stage of decomposition begins at a temperature of about 350°C. At this stage, the fibre breaks down to form chars releasing water and carbon dioxide. With a further increase in temperature, the process of formation and digestion of chars takes place. The stable residual mass at 500°C temperature comes mostly from minerals and char residue (Gashti et al. 2013). Proximate analysis showed that hemp fibre had higher ash content on average than flax fibre (Table I). The TGA analysis also coincides with the proximate analysis showing a higher residual mass fraction at 500°C for hemp fibres. Conclusion The lower ash and ether extract and higher DM, CC and CF of these flax fibres make them (also) suitable for being used in the lightweight composite, textile, pulp and cellulose-based industries. The hemp fibre had higher ash which was reflected by a higher residue at 500°C in TGA analysis. High ash content in the hemp fibres will provide high thermal stability and could be used as reinforcement material for composite. Further investigations are needed to understand the viability of these flax fibres for different purposes. 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Doi: 10.19045/ bspab.2018.700131 Wielage B, Lampke T, Marx G, Nestler K and Starke D (1999), Thermogravimetric and differential scanning calorimetric analysis of natural fibres and polypropylene, Thermochimica Acta. 337(1-2): 169-177. 2016; Waris et al. 2018; Ishag et al. 2019; Alonso-Esteban et al. 2022). Although the physical properties of hemp and flax fibres are known to us (Girijappa et al. 2019), hitherto, no information on the proximate composition of fibres of Bangladeshi genotypes of these two important fibre-yielding crops is available. The constituent fibre properties influence application of textiles in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, as well as the apparel or clothing industry (Shuvo, 2020). We have, therefore, reported the proximate composition and thermogravimetric analysis data of 3 hemp and 6 flax genotypes here. Materials and methods The proximate analysis and thermogravimetric analysis (of fibres) of six flax genotypes and three hemp genotypes were carried out to understand their suitability in different applications. Hemp seeds were collected from different locations in Bangladesh (detailed collection information will be available upon request) and the genotypes are named accordingly, viz. Brammonbaria, Chittagang and Meherpur. The hemp plants were grown (in a confined area) at Botanical Garden, Department of Crop Botany, Bangladesh Agricultural University. Flax fibres were collected with the ribbon retting method (Roy et al. 2010) and sun-dried properly. The flax fibres of 6 genotypes, harvested from another experiment in the same year, were collected from the Laboratory of Plant Systematics of the same Department. The proximate composition analysis viz. dry matter (DM), crude protein (CP), crude fibre (CF), ash and ether extract (crude fat; EE), were accomplished at the Laboratory of Department of Animal Science, Bangladesh Agricultural University, Mymensingh following standard procedure (Kabir et al. 2018). The crude carbohydrate was calculated following Mundaragi et al. (2017). Crude Carbohydrate (%) = 100 – [moisture (%) + protein (%) + fibre (%) + fat (%) + ash (%)] The calorific value or the total energy value of fruits in kcal100–1 g was calculated with the help of the following equation (European Parliament and Council of the European Union, 2011). Energy value (kcal 100–1 g) = 4 × Protein + 9 × Fat + 4 × Carbohydrate + 2 × Fibre