IJFS#1923_bozza Ital. J. Food Sci., vol. 32, 2020 - 815 PAPER PHYSICOCHEMICAL, RHEOLOGICAL, AND SENSORY EVALUATION OF VOLUMINOUS BREADS ENRICHED BY PURSLANE (PORTULACA OLERACEA L.) M. DELVARIANZADEHa, L. NOURIa, A. MOHAMMADI NAFCHI*b,a, and H. EBRAHIMIc aDepartment of Food Science and Technology, Damghan Branch, Islamic Azad University, Damghan, Iran bFood Technology Division, School of Industrial Technology, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia cRandomized Controlled Trial Research Center, Shahroud University of Medical Sciences, Shahroud, Iran *Corresponding author: amohammadi@usm.my ABSTRACT Portulaca oleracea (purslane) can be used as a vegetable and herb for medical and food products. The aim of this study was to investigate the psychochemical, rheological, and sensory properties of voluminous breads enriched by different amounts of purslane powder (0, 5, 10, and 15%) were compared to a control group. The results showed that, with an increase in the concentration of Purslane in samples, water absorption capacity, stability under mixer, and softening level increased. Adding 15% of purslane powder decreased farinograph quality number significantly. Addition of purslane powder also improved resistance to extension and decreased extendibility, energy, and viscosity of the dough significantly. In terms of sensory properties, the sample with 15% purslane powder obtained the minimum score and other samples had acceptable conditions in terms of different sensory properties like taste, texture, color, odor, and general acceptability. In summary incorporation of purslane in voluminous bread is feasible and the optimum percentage of the purslane powder is 10% for the best acceptance in sensory evaluation. Keywords: bread, Portulaca oleracea, Purslane, sensory evaluation, fortification, physichochemical properties Ital. J. Food Sci., vol. 32, 2020 - 816 1. INTRODUCTION Wheat products like flour and bread are good carries for adding nutrients needed by the consumers (EL KHOURY et al., 2018). In addition, bread is the staple food of about one half of the world population and a reliable source in terms of nutrition and inexpensive diet (GRAHAM, Welch, and Bouis, 2001). To improve nutritional support for low income families, it is essential to pay more attention to improving quality and diversity of available breads, minimize the wastes, and produce breads with strong sensory properties (GUYOT, 2012). Along with being a main source of energy, bread also supplies the dietary fibers, some minerals (iron (Fe), calcium (Ca), and vitamin B group and vitamin E (found in wheatgrass) (KAUR, 2011). Improvement of texture, volume, crust, and quality of bread is one of the advantages of using fat in bread formulation (EL-SOHAIMY et al., 2019). Another role that is filled is adding tastes and energy content of the product. As shown by the literature, fat tastes in breads are more desirable for the consumer than other tastes (HEENAN et al., 2008). Portulaca oleracea (purslane) is a grassy annual plant in the family Oleracea with succulent stems, yellow or white small flowers, black seeds, and medicinal properties. The wild plant is a watery weed that prefers warm and arid condition and grows in a wide range of soils and climates. According to the traditional medicine, the plant has a cold and moist humor, styptic, and diuretic and decreases bile sack movement and bile flow in return (ASADI GHARNEH and REZA HASSANDOKHT, 2008; NAEEM and KHAN, 2013). Purslane is a well-known plant in traditional medicine with protective effect on the liver that is used for several therapeutic purposes. It preserves the liver against the damages caused by free radical invasion and lipid peroxidation in the endoplasmic grid of cells (ZAREI et al., 2015) (HADI et al., 2018). In addition, purslane is rich of antioxidant compounds and a good source for flavonoid, and carotenoid (M. ALAM et al., 2014). In addition, there has been no report of toxic effects of this plant. In addition to the said effects, purslane demonstrated anti-pain and anti-inflammatory effects. It is the richest plant source of W-3 (M. ALAM et al., 2014; UDDIN et al., 2014). Total fat content of the leaves range from 1.5 to 2.5 mg/g of fresh mass out of which around 60% and 40% is α- Linolenic acid (C18:3ω3) (LIU et al., 2000). Nowadays, researchers are looking for the ways to enrich food products, meet nutritional needs, and improve health in the consumers. So far, different additives have been added to bread formulation such as purslane seed flour (FATHNEJHAD KAZEMI et al., 2012), flaxseed flour (MERVAT et al., 2015), fenugreek flour (NASEHI et al., 2018), and garlic flour (BALESTRA et al., 2011). In addition, the importance of using medicinal plants in pharmaceutical and economic fields is quite clear (BHAT et al., 2013; DANESHZADEH et al., 2020; GUARIGUATA et al., 2014; WHITING et al., 2011). Taking into account the high rate of linolenic fat acid in some of oil seeds like purslane seed, the high consumption rate of bread, and low consumption rate of essential fatty acids per capita, the present study is an attempt to survey the possibility of using purslane to enrich voluminous breads to improve physicochemical, rheological, and sensory qualities of the breads. Ital. J. Food Sci., vol. 32, 2020 - 817 2. MATERIALS AND METHODS 2.1. Purslane powder preparation Shahroud strand of purslane plant was collected from a vineyard in Shahroud, Semnan Province, Iran. The plats were washed with distilled water to remove dust, cleaned, and dried at room temperature (35±2°C) for several days till complete dryness and then powdered using a laboratory grinder (Pars Khazar, Rasht, Iran). The powder was sieved using a sieve with mesh size of 0.5 at most. The obtained powder was kept in a capped container in fridge (0-4°C). 2.2. Voluminous bread samples preparation As the control group, voluminous bread formulation is listed in Table 1. To prepare the samples and according different levels of purslane powder to replace wheat flour (0 (control), 5, 10, and 15% w/w) was mixed with wheat flour, yeast suspension (2%) and other ingredients using an electrical mixer and incubated at 30°C for 30 minutes (Pars Khazar, Rasht, Iran). Water content was determined using farinograph and the dough was mixed for 10min. To mix the dough, spiral mixer was used, and the dough was cut into 150 gr pieces. The baking process took 25-30 min at 180°C in an electrical convection oven (SM-705E Model, SINMAG, Jakarta, Indonesia). Afterwards, the breads were cooled down and packed in polyethylene packages for further examination (SHITTU et al., 2009). Table 1. Voluminous bread formulation. Ingredients Amounts Flour 1 kg Sugar 10 g Yeast 10 g Vegetable oil 10 g Salt 5 g Water Enough 2.3. Physicochemical and Rheological analysis 2.3.1 Analyzing wheat flour, purslane powder, and voluminous breads Moisture, ash, total protein, fat, raw fiber, falling number, and moist gluten were determined according to AACC method (2000) under code numbers 44-15A, 08-01, 46-13, 30-10, 32-10, 81-56, 54-11, and 12-38, respectively (AACC, 2000). 2.3.2 Dough rheological analysis To examine amylograph properties of dough samples, an amylograph device (Brabender, Germany) was used based on the standard instruction. Rheological properties of different samples were determined using farinograph and amylograph based on AACC method Ital. J. Food Sci., vol. 32, 2020 - 818 (2000) No. 54-21 and 54-30. Then different parameters like water adsorption, dough development time (DDT), stability of dough, and mixture resistance index were plotted on farinograph diagrams and parameters like gelatinization and viscosity were extracted based on amylograph diagram (AACC, 2000). 2.3.3 Physicochemical analysis of voluminous bread The bread samples were analyzed using AACC (2000). The moisture, raw protein content, fat content, ash content, and gluten content were determined through 44-15, 46-13, 30-25, 01-08, and 38-11 methods respectively (AACC, 2000). 2.4. Sensory evaluation The quality of breads, fresh and cooled down in ambient temperature, was examined by 20 trained examiners (10 men and 10 women) were analyzed. Sensory specifications included tastes, texture, color, odor, and general acceptability. The samples were coded randomly and provided to the examiners in separate containers. They scored the samples based on a five-point scoring system (5= very good, 4 = good, 3= moderate, 2= bad, and 1= very bad) (GHANBARI and FARMANI, 2013; YASEEN et al., 2010). 2.5. Statistical analysis All experiments were done with three replicates using ANOVA in SPSS 22 (Chicago, IL, USA). To compare mean score (P<0.05), Duncan’s multiple range test was used. The independent variable was different levels of purslane powder and dependent variables were all the experiments on the treatments. Figures were developed in MS Excel. 3. RESULTS AND DISCUSSION 3.1. Physicochemical properties of wheat flour and purslane powder Physicochemical properties of wheat flour and purslane are listed in Table 2. As listed, moisture of wheat flour is higher than that of purslane powder; while purslane powder has higher fat, protein, total ash, and fiber content compared to wheat. Purslane powder did not have gluten and alpha amylase activity. 3.2. Dough rheological analysis 3.2.1 Farinograph test on the dough Results of water absorption (WA) in farinograph test (Table 3) showed that by adding purslane powder into the wheat flour, WA capacity decreases notably so that the control sample contained 57.96% water and the sample containing purslane powder (15%) only contained 55.1% water. Still, the decrease in WA rate in the samples with 5 and 10% of purslane powder was not significant (p>0.05). Since, purslane powder contains hydrophobe chemical compounds like fatty acids, the decrease in WA capacity by adding purslane powder is expectable. Ital. J. Food Sci., vol. 32, 2020 - 819 As listed in Table 3, by increasing the level of purslane powder in dough sample, stability time in mixture decreases. Dough Stability (DS) time in the control sample was 4.98min and for the samples with 5, 10, and 15% purslane powder, this time was 4.63, 4.26, and 3.65 min respectively. The decrease in stability time by replacing wheat flower by purslane powder is rooted in dilution or degradation of gluten grid. Physical break of gluten grid can be a reason for the less stable dough as gluten proteins are responsible for viscoelastic grid and stability of dough and purslane powder does not contain gluten. (MACRITCHIE, 2010). Table 2. Physico-chemical properties of wheat flour and purslane powder. Parameters Wheat flour Purslane powder Moisture (%) 13.83±0.59a 4.72±0.45b Protein (%) 8.89±0.33b 16.39±0.24a Fat (%) 1.49±0.14b 4.79±0.06a Ash (%) 0.72±0.11b 18.12±0.08a Crude fiber (%) 0.13±0.03b 4.78±0.05a Wet gluten (%) 24.16±0.27 - Felling number (Seconds) 353 - *Different letters in the same row indicate significant differences (P<0.05). The degree of loosening analysis showed that by adding high levels of purslane powder to the dough samples, looseness of the sample increased notably after 12 min (Table 3). This increase in looseness can be explained by the dilution of gluten proteins that weakens the dough. Purslane powder also contains unsolved fibers that weaken gluten functions. Dough weakening levels for the control and samples with 5, 10, and 15% purslane powder were 89.68, 91.29, 95.13, and 100.85 BU respectively. Farinograph quality number (FQU) for different samples is listed in Table 3. Clearly, adding purslane powder to the dough sample (15%) caused a significant decrease in FQU (p<0.05) as adding the powder decreases stability of the dough. In general, there was no significant difference between FQU of the control and purslane samples 5% and 10% (p>0.05). XU et al. (2014) showed that adding linseed flour to wheat flour increased WA, dough expansion time, and dough resistance (XU et al., 2014). GARDEN (1993) consistently found that mixing linseed and wheat flour decreased stability of dough significantly (Garden- ROBINSON, 1993). KOCA and ANIL (2007) reported that the reason for the difference in the mixture of dough containing linseed was dilution of gluten protein by fiber and the reaction between fiber materials and gluten, which also affects the mixing process (KOCA and ANIL, 2007). Farinograph results by KOCA et al. (2007) showed that by increasing linseed content, WA, dough expansion, and mixture resistant index increased; while DS decreased by adding different levels of linseed (KOCA and ANIL, 2007). These findings are consistent with the present study. Ital. J. Food Sci., vol. 32, 2020 - 820 Table 3. Farinograph characteristics of dough samples. Samples Moisture absorption (%) Dough stability time (min) Degree of loosening (after 12 minutes fermentation) (B.U.) Farinograph qualitative number Control 57.96±0.42a 4.98±0.32a 89.68±2.42c 58.16±2.37a 5% of purslane powder 56.39±0.59 b 4.63±0.19ab 91.29±2.01bc 57.89±1.14a 10% of purslane powder 55.61±0.32 bc 4.26±0.29b 95.13±1.94 b 53.91±2.02a 15% of purslane powder 55.11±0.48 c 3.65±0.24c 100.85±2.06a 47.96±1.68b P-value 0.000 0.000 0.000 0.013 *Different letters in the same column indicate significant differences (P<0.05). 3.2.2 Extensograph test on dough Rheology tests with large deformation range, including one-side extension test using an extensograph device yielded information about viscoelastic behavior of dough and dilatancy of gluten grid (GILBERT, 2002). Since, extensograph results have direct relationship with gluten protein properties, changes in dough resistance to extension and extendibility of dough can be attributed to the interactions between fiber structure and gluten protein. The results of the effects of different concentration of purslane powder on extension strength of the dough (Fig. 1a) showed that with a longer rest time of 45-135 min, extension strength of the samples increased significantly both in the control and experiment groups (p<0.05). The dough rest was in extensograph container and during resting and due to changes in glutens, the ingredients were revived and a uniform gluten grid was reestablished due to the changes in gluten (XU et al., 2014). Therefore, extension strength after the rest time is improved. At different rest times (45, 90, and 135min), adding purslane powder increases tensile strength of dough due to high fiber content of the powder. In general, the highest level of tensile strength happened in the samples with 15% purslane content and fermentation time of 135min (247.75 BU) and the lowest level was with the control sample with fermentation time of 45min (169.77 BU). Extendibility levels of different dough samples are demonstrated in Fig. 1b. Clearly, in the samples with different concentrations of purslane, extendibility is notably less than the control samples (p<0.05). This can be due to the larger size of purslane powder particles compared to wheat flour that causes early rapture of gluten under extension. The second cause might be dilution of dough protein so that changes the ratio protein to starch (MACRITCHIE, 2010), the increase in tensile strength and decrease in its extendibility with different concentration of purslane powder is justifiable. In short, with different fermentation times, the highest extendibility was observed with the control sample and the lowest level was observed with the control sample with fermentation time of 45 min (14.73 cm). Ital. J. Food Sci., vol. 32, 2020 - 821 Figure 1. Comparison of mean values of (a) dough elasticity (cm), (b) tensile strength of dough (BU), (c) energy (cm2) of different dough samples during different fermentation times. Different letters on bars represent significant differences among means. The area under diagram and dough energy indicates the energy or mechanical work needed for extending the dough until rapture. This is a reliable index of dough strength. For academic purposes, the curve height and the area under it are considered as strength index and the higher this index, the higher the strength of dough (GILBERT, 2002). The mean area under the diagram or tough energy of different dough samples containing different concentration of purslane powder with fermentation periods 45, 90, an d135min in extensograph is illustrated in Fig. 1c. The highest and lowest levels of dough energy with different fermentation time were obtained by the control and purslane powder (15%) respectively. There was no significant difference between the energy level of the samples with 5 and 10% of purslane powder regardless of fermentation time. Still, the increase in fermentation concentration time from 10 to 15% had a significant effect on the dough energy (considerable decrease). The sample with different levels of purslane powder Ital. J. Food Sci., vol. 32, 2020 - 822 demonstrated a gradual increase in energy level of dough with an increase in fermentation time in the extensograph. MARIOTTI et al. (2006) reported rheological and baking performance specifications of bread with different levels of Avena sativa flour and showed that adding Avena sativa decreased WA and strength of breads (MARIOTTI et al., 2006). STEPNIEWSKA et al. (2019) examined the quality of breads with rye flour and found that lower protein content, lower unsolved total pentosan content, higher solved pentosan content in water, flour granola, and solved content in water (pentosan in particular) had a significant effect on the hardiness of bread samples (STĘPNIEWSKA et al., 2019). Marie and Ivan (2017), consistent with our findings, reported that replacing linseed fiber had a significant effect on the energy of extensogram curve (MARIE and IVAN, 2017). 3.2.3 Amylograph analysis Table 4 lists the results about the effect of different levels of purslane powder on gelatinization of wheat flour-based dough. Clearly, despite the trivial increase in gelatinization temperature (GT) caused by the increase in the volume of purslane powder in the samples, there is no significant difference between the control and experiment samples in terms of GT (p>0.05). Table 4. Amylograph results of dough samples. Variables Control 5% 10% 15% Gelatinization temperature (°C) 58.37±0.08 a 58.39±0.09a 58.46±0.05a 58.51±0.08a Viscosity (BU) 1941.2±4.7a 1929±5.4 b 1917.5±2.9c 1906.2±4.1 d *Different letters in the same column indicate significant differences (P<0.05). Viscosity of the control and experiment samples is listed in Table 4. Clearly, the control sample has the highest viscosity (1941.2 BU) and adding purslane powder created a significant decrease in viscosity of the samples (p<0.05). That is, viscosity levels in the samples with 5, 10, and 15% of purslane powder were 1929.0, 1917.5, and 1906.2 BU respectively. The reason for this decrease in viscosity after adding purslane powder to the sample can be the decrease in gluten protein content. Therefore, with an increase in purslane concentration, the continuous grid of gluten is broken and viscosity declines (SALIM-UR-Rehman, 2006; YOUSIF et al., 2012). SALIM-UR-REHMAN et al. (2006) showed that increasing the content of sorghum flour up to 30%, lowered the viscosity of dough (SALIM-UR-REHMAN, 2006). INDRANI et al. (2015) reported that adding ground black gram to dough sample increased viscosity of the dough samples notably. Their results are consistent with the results here (INDRANI et al., 2015). MLAKAR et al. (2009) showed that replacing amaranthus flour up to 10% did not have any effect on GT of wheat flour dough, while adding 20% amaranthus flour increased starch GT (MLAKAR et al., 2009). Moreover, a significant decrease in viscosity of the dough due to adding amaranthus flour was reported. Ital. J. Food Sci., vol. 32, 2020 - 823 3.3. Bread samples analysis 3.3.1 Bread moisture content Fig. 2a illustrates results of moisture assessment of the samples with different levels of purslane. Clearly, the lowest moisture level is with the control sample (33.53%) and the moisture increases significantly with the increase of purslane content to 5 and 10% (p<0.05). Still, the increase in purslane powder level from 10 to 15% decreases moisture content. The increase in moisture content with the lower levels of purslane can be explained by the high fiber content in purslane, which preserves moisture in the samples. Still, with further increase in purslane content, gluten grid is degraded and its capacity to store water decreases. The powder contains hydrophobic chemical compounds like fatty acids that decrease water content. DEMINE et al. (2013) showed that adding quinoa flour to flour formulation creates a significant decrease in moisture content of bread samples (DEMIN et al., 2013). Still, the increase in quinoa flour did not have a significant effect on bread samples moisture. GOHAR et al. (2016) stated that replacing a part of wheat flour with quinoa flour decreased moisture content significantly (GEWEHR et al., 2016). As to the increase in moisture content after adding amaranthus flour to the formulations used by baking industries, INGLETT et al. (2015) studied cookies containing amaranthus flour. They showed that adding amaranthus flour increased moisture capacity in baking process comparing with other samples (INGLETT et al., 2015). TEUTONIC and KNORR (1985) showed that amaranthus seeds have 3.54% lignin and this increases the capacity to store water (TEUTONICO and KNORR, 1985). In addition, ELGETI et al. (2014) used quinoa flour and replaced it with rice and corn flour up to 40- 100% to obtain gluten free bread. The results showed that along with improving the volume of bread, quinoa flour created a softer inner texture, distributed air cell more evenly, had a positive effect on moisture content of the samples and delayed going stale (ELGETI et al., 2014). They argued that the increase in moisture content of the samples was due to adding fiber-rich flour (e.g. lignin) to the samples. 3.3.2 Breads protein content Fig. 2b illustrates protein content of the samples. Clearly, the minimum protein content appears in the control sample (10.05%) and since purslane powder contains more protein than wheat flour, adding purslane powder to the formulation created a significant change on protein content (p<0.05) so that samples with 5%, 10%, and 15% purslane powder contained 11.82%, 12.48%, and 12.91% protein content respectively. HOSSEIN and SALEM (2016) studied enrichment of gluten-free snacks using different levels of purslane and showed that adding purslane increased protein content of the products significantly (HUSSIEN and SALEM, 2016). ASMA and GINDY (2017) showed that adding purslane powder to bread samples increased protein content significantly (ASMA and GINDY, 2017). ALMASOUD and EMAN (2014) found that adding purslane significantly increased protein content of crackers (ALMASOUD and EMAN, 2014). These findings are consistent with our findings. Ital. J. Food Sci., vol. 32, 2020 - 824 Figure 2. Comparison of (a) protein, (b) moisture, (c) ash, (d) fat and (e) fiber content (%) of different bread samples. Different letters on bars represent significant differences among means. Ital. J. Food Sci., vol. 32, 2020 - 825 3.3.3 Breads fat content Fat content results are demonstrated in Fig. 2c; clearly, the control sample has the lowest fat content (0.65%) and adding purslane powder makes a significant change in fat content (p<0.05). That is, samples with 5%, 10%, and 15% purslane powder contain 1.01, 1.25, and 1.53% fat respectively. Taking into account the fatty nature of purslane, the increase in fat content is expectable. DESTA and MOLLA (2020) suggest that the highest oil content was observed in seed (DESTA, 2020) in the present study, all parts of the plant have been used. HOSSEIN and SALEM (2016) argued that increasing purslane powder in gluten-free stack formulations increased fat content significantly (HUSSIEN and SALEM, 2016). ASMA and GINDY (2017) studied the increase in fat content of breads through increasing purslane level in the formulation (ASMA and GINDY, 2017). 3.3.4 Total ash content of breads Fig. 2d illustrates total mean ash content of the control and experiment samples. Clearly, the lowest ash content is observed with the control sample (2.85%) and since purslane powder contains higher levels of mineral elements, it yields more ash than wheat flour (ALAM, Juraimi, Yusop, Hamid, and Hakim, 2014). By increasing the share of purslane in the formulation, a significant increase in ash content takes place (p<0.05). The samples with 5%, 10%, and 15% of purslane powder yielded total ash volumes of 3.28%, 3.49%, and 3.68% respectively. A study by IGLESIAS-PUIG et al. (2015) on the breads produced with quinoa total flour showed that with an increase in quinoa flour, ash content increases, which is consistent with our findings (IGLESIAS-PUIG et al., 2015). A study by HOSSEIN and SALEM (2016) reported similar results so that an increase on purslane powder content in gluten-free snacks increased ash content of the products significantly (HUSSIEN and SALEM, 2016). ASMA and GINDY (2017) showed that an increase of purslane powder in bread formulation significantly increased ash content of the samples, which is consistent with our results (ASMA and GINDY, 2017). As the ash increases, the amount of minerals in the raw material increases (UDDIN, 2012). 3.3.5 Bread fiber content Raw fiber content in the control and experiment samples is illustrated in Fig. 2e. Clearly, the higher fiber content of purslane powder compared to wheat flour increases the fiber content significantly (p<0.05). With an increase in purslane content in the sample, the fiber content increases significantly. The control sample have 0.69% fiber and the samples with 5%, 10%, and 15% purslane powder have 1.02, 1.32, and 1.59% fiber content respectively. HOSSEIN and SALEM (2016) showed that an increase in purslane powder content in gluten-free snack increased fiber content significantly (HUSSIEN and SALEM, 2016). A study by ASMA and GINDY (2017) showed that using purslane powder in the sample increased fiber content (ASMA and GINDY, 2017). ALMASOUD and EMAN (2014) consistently reported that adding purslane formulation to cracker increased fiber content notably (ALMASOUD and EMAN, 2014). Ital. J. Food Sci., vol. 32, 2020 - 826 3.3.6 Sensory evaluation of bread Mean scores of taste, texture, color, odor, and general acceptability of the samples are illustrated in Fig. 3. Figure 3. Comparison of (a) texture, (b) taste, (c) odor, (d) color and (e) overall acceptance score of different bread samples. Different letters on bars represent significant differences among means. Ital. J. Food Sci., vol. 32, 2020 - 827 The control sample obtained the total score of taste, color, and general acceptability. In addition, the control and 5% samples obtained total score of texture and odor as well. Still, there was no significant difference between the control and 5% samples in terms of taste and general acceptability (p>0.05). Adding purslane powder to the bread formulation significantly lowered taste and general acceptability scores (p<0.05) so that the sample with 15% purslane content had the lowest score of color. Except for the 15% sample, the rest of the treatments were acceptable in terms of sensory indices. By increasing purslane content from 5% to 15%, texture, taste, and general acceptability scores declined (p<0.05) so that the 15% sample obtained the lowest scores of texture, odor, and general acceptability (FATHNEJHAD KAZEMI et al., 2012). Still, all the treatments were acceptable in terms of texture, odor, and general acceptability. High purslane content in the formulation decreased volume and moisture content of the breads and had a negative effect on the texture. The decrease in color score by adding purslane powder content can be explained by the dark color of purslane powder. HOSSEIN and SALEM (2016) showed that adding 5% of purslane powder had a significant effect on sensory acceptability of gluten- free snacks (HUSSIEN and SALEM, 2016). However, adding 10 and 15% of purslane powder resulted in a decrease in sensory score of products. However, all the enriched samples were acceptable in terms of sensory specifications. MERVAT et al. (2015) maintained that adding 10% of linseed flour with total fat content did not have a significant effect on sensory acceptability (MERVAT et al., 2015). GANORKAR and JAIN (2014) noted that dry crust, a decrease in tenderness, and feeling roughness in the mouth were the reasons for a decrease in general acceptability score after adding linseed to cookies formulation (GANORKAR and JAIN, 2014). These results show that increasing the additive content increases tenderness of the product due to the higher content of fatty acids content; however, color, odor, and general acceptability decrease, which is consistent with our results. The reason for the noticeable decrease in the sensory score of the samples containing higher percentages of Portulaca oleracea was due to the black color of the Portulaca oleracea and its effect on the color of the bread samples. But in the MELILLI et al. (2020) study, the sensory score of 5% obtained the highest sensory score (MELILLI et al., 2020). It seems that this discrepancy is due to the difference of different varieties in different parts of the world and it is predicted that if the yellow varieties of portulaca are used, such a decrease will not be observed in fortified breads with a higher percentage of 10% Portulaca oleracea 4. CONCLUSION hysicochemical, rheological, and sensory properties of voluminous wheat flour breads containing different levels of purslane powder were examined. An increase in purslane content in dough samples decreased DS against mixture and increased looseness level. Adding 15% of purslane powder decreased FQU significantly. In addition, despite the increase in extension strength and a significant decrease in dough extendibility, energy, and viscosity of the dough sample, the increase in GT was not notable. Moreover, increasing the content of purslane powder increased protein, fat, total ash, moisture, and fiber content of the samples compared to the control samples. 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