Microsoft Word - 164.docx


CHEMICAL ENGINEERING TRANSACTIONS 

VOL. 56, 2017 

A publication of 

The Italian Association 
of Chemical Engineering 
Online at www.aidic.it/cet 

Guest Editors: Jiří Jaromír Klemeš, Peng Yen Liew, Wai Shin Ho, Jeng Shiun Lim 
Copyright © 2017, AIDIC Servizi S.r.l., 

ISBN 978-88-95608-47-1; ISSN 2283-9216 

Drying and Preservation of Phytochemicals from 

Elateriospermum Tapos Seed Oil using Combination of 

Freeze Drying and Microwave Technique 

Nor Diana Hassana, Ida Idayu Muhamad*,a,b 

aBioprocess Engineering Department, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor 

 Bahru, Johor, Malaysia 
bCardiovascular Engineering Centre IJN-UTM (Biomaterial Unit), Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, 

 Johor, Malaysia 

 idaidayu@utm.my 

Elateriospermum Tapos seed oil (ETSO) or known as perah seed oil contain high concentration of omega 3 

fatty acid and exposed to lipid oxidation in the form of free oil.  In this work, microencapsulation process of 

ETSO was formulated by using combination of freeze drying and microwave technique assisted freeze drying 

using maltodextrin (MD) and sodium caseinate (SC) as wall materials in order to protect the oil from oxidation. 

This kind of drying technique is a new technology of oil microencapsulation with faster drying time than 

conventional freeze drying. The main goal of this study was to evaluate the microencapsulation process on the 

physical and chemical characteristic of oil microcapsule. The microencapsulation effectiveness was 

determined in base of process yield and the microencapsulation efficiency. The white dry microcapsules were 

subjected to Field Emission Scanning Electron Microscope (FESEM) to study the powder morphology, Fourier 

Transform Infrared Spectroscopy (FTIR) to study chemical bonding and thermogravimetric (TGA) for thermal 

profile. Highest encapsulation yields of 82 % and microencapsulation efficiency of 42 % were achieved when 

the compositions of wall material used as encapsulation agents were 75 % maltodextrin and 25 % sodium 

caseinate, freeze drying time was 7 h and the ratio of oil-wall material was 1 : 4.  

1. Introduction

Nowadays, consumers are becoming more concern on nutritious and healthier food. The benefits of omega-3 

fatty acids such as their potential role in reducing the risk of coronary heart disease, inflammatory and immune 

disorders, colon cancer and in improving early development lead to the fortifications of oils with high in long 

chain omega-3 fatty acids in many food products. Pertaining to the abundance of unsaturated fatty acids and 

tocopherols in vegetables oil, they contribute the greater demand of the latter. ETSO is new local source of 

seed oil containing high linolenic acid (18 %) along with oleic acid (32.5 %) and linoleic acid. Perah seed 

demonstrates considerate amounts of other bioactive components, such as tocopherols (vitamin E), squalene 

and L.beta-sitosterols (Tan et al., 2013). Oil extracted from the seed can be applied in various food products. 

The fortification of oil in food products are impaired by chemical instability and exposed to oxidative damage 

when bared to oxygen, moisture, temperature and light due to the existence of polyunsaturated fatty acids. 

The oxidative deterioration leads to nutritional loss, unpleasant flavours, reduce shelf life and sensory 

properties of the oil (Calvo et al., 2010).  

Oil microencapsulation has been applied in food industry to overcome those issues especially to protect food 

ingredients such as essential oils, colourant, lipid and flavours against oxidation (Goula and Adamopoulos, 

2012). Wall system around the encapsulated material provide a barrier to protect the food ingredients from 

oxidation during food production and storage.The wall system also produces powders products with new 

properties and also controllable release during consumption (Adamiec and Kalemba, 2006). Many techniques 

of microencapsulation can be accomplished such as spray drying, freeze drying, extrusion, coacervation 

liposome entrapment, inclusion complexion, co-crystallisation, interfacial polymerisation and microwave. 

 

   

DOI: 10.3303/CET1756168

 

 

 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

 

 

 
 

Please cite this article as: Hassan N.D., Muhamad I.I., 2017, Drying and preservation of phytochemicals from elateriospermum tapos seed oil 
using combination of freeze drying and microwave technique, Chemical Engineering Transactions, 56, 1003-1008  DOI:10.3303/CET1756168   

1003



Drying is an important step in microencapsulation for storage purpose, normally in powder form. Freeze drying 

is known best to encapsulate heat sensitive material. However, the highest cost of freeze drying amongst of all 

drying operations become a constraint to its application (Velasco et al., 2003). Reducing drying time is one of 

the key research topics to improve the process economics. Combination of freeze drying and microwave is 

one of the promising microencapsulation technique to reduce cost by minimising the freeze drying time.  

2. Materials and method 

ETSO was obtained from local farm in Kuala Lipis, Pahang. Reagents such as sodium caseinate brand 

Sigma, Germany, maltodextrin brand Aldrich, USA and hexane were obtained from Syarikat Pustaka Elit, 

Johor. 

2.1 Microencapsulation process 

ETSO microencapsulation was performed by the formation of an emulsion of the core material (oil) in the wall 

solution using modified method of Calvo et al. (2012). Three different microcapsule models were evaluated in 

the present study. Different ratios oil and wall material (1 : 1, 1 : 4, 1 : 7) were evaluated for each studied wall 

materials. The emulsion was prepared by mixing ETSO with different percentage of wall solution (75 % MD:  

25 % SC, 50 % MD : 50 % SC, 25 % MD : 75 % SC) at room temperature using a hot plate magnetic stirrer for 

2 h. The prepared emulsion was frozen at −80 °C, freeze-dried by a lyophiliser (Alpha 1-2 LD Plus, Martin 

Christ, Germany) from 1 to 7 h instead of 1 to 2 d of normal operation. After the lyophilisation process, 

microcapsules were dried in microwave power 110 kW for 10 min. Then the microcapsules were grinded and 

transferred to double layer plastic bags.  

2.2 Moisture 

This analysis was conducted using Infrared Moisture Determination Balance (Kett, FD-620, Japan). 2.0 g of 

sample was used and heated at temperature 105 °C. Triplicates reading of moisture content and average 

were taken for each sample. 

2.3 Microencapsulation Yield 

The yield of extraction was calculated in terms of mass percentage as shown in Eq(1) followed the method 

used by Mohd Fauzi et al.  (2011). 

𝑌𝑖𝑒𝑙𝑑 (%) =
 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑜𝑖𝑙 𝑒𝑥𝑡𝑟𝑎𝑐𝑡𝑒𝑑 (𝑔)

𝑚𝑎𝑠𝑠 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒 (𝑔)
 ×100 %   (1) 

2.4 Microencapsulation Efficiency 

Microencapsulation efficiency modified procedure Calvo et al. (2012) was analysed after microencapsulation 

process. This analysis serves to caluculate the amount of unencapsulated oil present. 2.5 g of microcapsules 

was will be weighted in a beaker and 25 mL of hexane will be added and shaken by hand for 20 s at room 

temperature to extract superficial oil. A filter paper was used to filter the solvent mixture. Then, 

unencapsulated oil will be collected after removal of hexane. The same microcapsules powder was extracted 

by soxhlet extractor for 6 h using hexane as extracting solvent to determine the encapsulated oil. After that, 

hexane was removed and the extracted oil was measured.  Microencapsulation efficiency (ME) was measured 

according to Eq(2). Total oil is calculated by the percentage of free oil content as described by Calvo et al. 

(2012). 

𝑀𝐸  =  
𝑇𝑜𝑡𝑎𝑙 𝑂𝑖𝑙−𝑆𝑢𝑟𝑓𝑎𝑐𝑒 𝑂𝑖𝑙  

𝑇𝑜𝑡𝑎𝑙 𝑂𝑖𝑙
× 100 %   (2) 

2.5 Fourier Transform Infrared Spectroscopy (FTIR)  

FTIR unit was equipped with a deuterated triglycine sulphate (DTGS) as a detector and a KBr Germanium as 

a beam splitter, interfaced to a computer operated under windows based and connected to OMNIC operating 

software system was used for FTIR spectra acquisition. Automatic dehumidifier was used to diminish water 

vapor interface from the machine. A few drop of each sample were put onto the Attenuated Total reflectance 

(ATR) multibounce plate of crystal at controlled ambient temperature (25 °C). All spectra were recorded from 

4,000 to 400 cm-1 co-adding 32 interferograms with measurement accuracy in vc the frequency data at each 

measured point of 0.01 cm-1, due to the laser internal reference of the instrument. Each time this spectrum 

was subtracted from the background air spectrum. A new air spectrum was taken after every scan with 

sample. The ATR plate was carefully cleaned with ethanol and was dried with a soft tissue before taking the 

spectra of a new sample. 

1004



2.6 ThermoGravimetric Analysis (TGA) 

TGA was carried out on a TA 2050 Instrument under nitrogen or air atmosphere at a purge rate of 50 mL/min. 

For each experiment, a sample of approximately 10 mg was used. A heating rate of 10 °C/min was applied, 

and the temperature was raised from 20 to 800 °C. In addition to the weight loss percentage (TG) curves, the 

derivative weight loss percentage (DTG) was calculated for each sample. 

2.7 Field Emission Scanning Electron Microscope (FESEM) 

Morphological study on the oil microcapsule powder will be observed by FESEM. It is be operated with 

X1,000, X25,000 and X100,000 magnification at 25 kV. 

3. Result and discussion 

Three oil microcapsules samples (sample A, B and C) were formulated with different percentage of wall 

compositions, different ratio oil to wall and different drying time to evaluate the microencapsulation process by 

freeze drying and microwave on the physical and chemical characteristic of the oil microcapsule. 

Microencapsulation formulation of sample A, B and C are summarised in Table 1. 

Table 1:  Microencapsulation of ETSO by using maltodextrin and sodium caseinate as wall materials 

Sample Encapsulant 

compositions 

(% MD - % SC)  

Ratio  

oil-wall 

Freeze Drying 

Time (h) 

Moisture content 

(%) 

M. Efficiency  

(%) 

M. Yield  

(%) 

A 75 % MD, 25 % 

SC 

1 : 1 4  8.16 11.59 82.18 

1 : 4 1  9.15 37.23 82.15 

1 : 4  7  0.94 42.69 84.73 

1 : 7 1  7.40 6.18 82.49 

1 : 7 4 4.88 36.55 83.69 

B 50 % MD, 50 % 

SC 

1 : 1 1  11.70 3.92 80.94 

1 : 1 7  4.22 9.88 81.26 

1 : 4 4  2.23 28.77 84.77 

1 : 7 1  8.39 17.96 82.49 

1 : 7 7  2.12 26.58 81.38 

C 25 % MD, 75 % 

SC 

1 : 1 4  5.79 4.23 81.68 

1 : 1 7  2.85 15.22 80.44 

1 : 4 1  5.78 14.45 82.39 

1 : 4 7  0.25 18.85 80.69 

1 : 7 4  2.55 10.56 81.11 

 

From Table 1, it can be seen that increasing ratio oil to wall materials and increasing the percentage of sodium 

caseinate reduce the moisture content at same drying time. Moisture content is the most influence factor in 

promoting lipid oxidation especially in oil microencapsulation. High value in moisture content will contribute the 

increment of omega-3 degradation and encouraging the growth and development of molds, bacteria and other 

microorganisms as stated by Dian et al. (1996). Moisture content gives high influence on physical changes of 

the solid matrix of microencapsulated oils and lead to the accessibility of oxygen to the oil. Relative protection 

of a high-viscosity solid matrix in the glassy amorphous state is achieved after drying process of 

microencapsulated oil (Velasco et al., 2003). It is suggested that combination of 75 % MD and 25 % SC with 

ratio oil to wall is 1 : 4 with 7 h drying time by freeze dryer could be a good coating material for 

microencapsulation of ETSO which highest encapsulation efficiency about 42.69 %. This result is an 

agreement with Calvo et al. (2012) with better encapsulation efficiency by increasing the percentage of 

maltodextrin. Velasco et al. (2003) concluded that freeze-dried samples showed lower microencapsulation 

efficiency compared to hot air drying but more resistant to oxidation. All formulation gives good encapsulation 

yield more than 80 %. 

3.1 FTIR 

Figure 1 showed FTIR spectra of control, microcapsule sample A, B and C. Microcapsule sample and control 

showed clear band shift at 2,926 cm-1 and 2,849 – 2,855 cm-1, attributed to the symmetric and assymetric 

stretching vibration of the aliphatic CH3 and CH2 group which is typical functional group of fatty acids in ETSO. 

FTIR spectra of microcapsule samples showed the characteristic bands and intense peaks corresponding to 

1005



proteins which attribute to sodium caseinate as wall material at 1,638 – 1,655 cm -1.The FTIR spectra for all 

microcapsule samples were found identical which showed similar characteristic phenomena. Microcapsule 

 

 

Figure 1: FTIR spectrum of ETSO, microcapsules sample A (encapsulant compositions: 75 % MD, 25 % SC), 

sample B (encapsulant compositions: 50 % MD, 50 % SC) and sample C (encapsulant compositions: 25 % 

MD, 75 % SC). 

sample spectrum demonstrated a broad band at 3,367 – 3,393 cm−1 which can be attributed to O-H stretching 

vibrations. The peak at 1,746 cm−1 represented the ester carbonyl bond (C-O) functional group of the 

triglycerides. Maximum absorbance at 3,009 cm-1 for control is due to the composition as vegetable oils 

contain higher proportion of linolenic or linoleic acyl groups. The clear shift of the 3009 cm−1 band is noticed in 

microcapsule samples, attributed to the C-H stretching vibration of cis-double bond, to the 3,008 - 3,014 cm−1 

bands. The structure of control and microcapsule samples is different due to the oil had undergone 

polymerisation by microencapsulation process. The spectral region between 2,700 cm-1 to 3,700 cm-1 

exhibited different intensity between microcapsule samples and control at same band shift. The control 

exhibited similar characteristic of ETSO which in agreement of the study done by Azlan Hadi Tan et al. (2013).  

3.2 TGA 

TGA analysis was aimed to investigate the thermal behaviour of samples from microcapsule powders of 

ETSO for sample A, B and C. The TGA curves of three formulations of ETSO microencapsulation are shown 

in Figure 2. All samples showed similar degradation patterns with three main thermal events referring to the 

, , , , , , , , , , , 

, 

, , 
, 

, 

, 

, 
, 

, 
, 

, 

, 

, , , , , , , , , , 

, 

, 

, 

, 

, 
, , 

, 

, 

, , 

, 

, 

, 

, 

, 

, 

, 

, 
, 

, , 

, 

, 
, 

, 

, 

, , , 

, 

, 
, 

, 

, 

, 

, 

, 

, 

, 

, 

1006



three materials used in the formulation; maltodextrin, sodium caseinate and ETSO. Sample C showed high 

thermal stability followed by sample A and sample B. By increasing the percentage of maltodextrin in wall 

compositions, mass loss has slightly increased which indicate slight changes to the microcapsules thermal 

stability. The first degradation occurred above 200 °C corresponding to degradation of polysaccharides 

(maltodextrin) which is an endothermic transition. In this stage, 21.4 %, 18.6 % and 16 % of mass loss for 

sample A, B and C is occurred, respectively. Bothara and Singh (2012) concluded in their study, 

polysaccharides start to decompose slowly at 250 - 280 °C and produce high char (86.8 % and 88.2 %) at the 

final temperature. The formation of H2O, CO and CH4 resulted from dehydration, depolymerisation and 

pyrolitic decomposition which are involved in these high temperature stages. The second degradation was 

observed around 300 °C corresponding to degradation of sodium caseinate (Marinho et al., 2015). In this 

stage, 33.1 %, 39.4 % and 25.2 % of mass loss for sample A, B and C is occurred, respectively. It seems that 

sample C has highest protein thermal stability. By decreasing the ratio of oil to core, the mass loss increased 

7.9 to 14.2 %, indicating a slight change in the microencapsulation thermal properties. Barreto et al. (2003) 

explained, the protein thermal degradation occured at temperatures above 300 °C since inter and intra-

molecular hydrogen bonding are broken up at raising temperatures during heating which lead to the gradual 

loss of the initial ordered structure of the polymer matrix. The third degradation was observed around 400 °C 

corresponding to autoxidation mechanism in the ETSO which are chain reactions initiated by the formation of 

free radicals. At initial stage of oxidation, the generation of primary oxidation products such are 

hydroperoxides are subsequently react with oxygen to form intermediate oxidation products such as 

aldehydes and acids which accelerating the degradation process These intermediate products evaporate at 

higher heating rates before they can react with oil solution that shifting to higher value. A relatively higher 

energy is needed initially to initiate the chain reactions but a lower energy used during the oxidation process 

occur as the accumulation of free radicals which is related to the concentration of free radicals and reactants 

is reached (Micic et al., 2015).  

 

Figure 2: TGA curves of different formulation of ETSO microencapsulation 

3.3 FESEM Analysis (Powder Morphology) 

Figure 3 demonstrate the morphology of ETSO microcapsules of sample A which gives highest 

microencapsulation efficiency of 42.69 %. The surface of microcapsule is irregular in structure and matrix type 

of encapsulation. The FESEM images of microcapsules obtained at lower magnification shows the porous 

structure and rough surface. The formations of spherical microcapsules were clearly showed with 

magnification of X100,000. The liquid product is first frozen and then the water is sublimated and dismissed in 

the freeze drying process. During freezing, from ice crystals or air bubbles retained and formed cavities which 

result the porous structure and the solid network should be able to support this porous structure. If the 

temperature of the dehydrating porous product is above Tg, the viscosity of the solid material may not be 

enough to hold the structure and lead to “collapse” or shrinkage (Fariasa et al., 2007). High oxidative stability 

1007



microcapsules powder during storage provides better oil protection against oxidation. The capsules have 

lower permeability to gases that protect the core material efficiently.  

 

Figure 3:  FESEM image of the sample A (Ratio oil-wall = 1 : 4, wall compositions = 75 % MD + 25 % SC, 

drying time = 7 h by freeze dryer + 10 min by microwave); Magnification of X1,000, X25,000 and X100,000. 

4. Conclusions 

Microencapsulation of ETSO by freeze drying and microwave technique has successfully shortened the drying 

time to achieve low moisture content compared to normal process of freeze dryer. The processing cost will be 

reduced. This study contribute to the progress of microencapsulation technology in processing and storage as 

well as exploring the benefits of underutilised seed in Malaysia. 

Acknowledgments  

The authors would like to thank Ministry of Higher Education (MOHE), Bioprocess Department of Faculty 

Chemical Engineering and Research Management Centre, UTM (grant Q.J1 30000.30449.00M80) for 

financial support of this project. 

Reference  

Adamiec J., Kalemba D., 2006, Analysis of Microencapsulation Ability of Essential Oils during Spray Drying, 

Drying Technology 24 (9), 1127-1132. 

Bothara S.B., Singh S., 2012, Thermal studies on natural polysaccharide, Asian Pacific Journal of Tropical 

Biomedicine 2 (2), S1031-S1035. 

Calvo P., Herna´ndez T., Lozano M., Gonza´lez-Go´mez D., 2010, Microencapsulation of extra-virgin olive oil 

by spray-drying: Influence of wall material and olive quality, European Journal of Lipid Science and 

Technology 112 (8), 852–858. 

Calvo P., Castaño A.L., Lozano M., González-Gómez D., 2012, Influence of the microencapsulation on the 

quality parameters and shelf-life of extra-virgin olive oil encapsulated in the presence of BHT and different 

capsule wall components, Food Research International 45 (1), 256-261. 

Dian N.L.H.M., Sudin N., Yusof M.S.A., 1996, Characteristics of microencapsulated palm-based oil as affected 

by type of wall material, Journal of Science of Food and Agriculture 70 (4), 422-426. 

Fariasa M.C., Mourab M.L., Andradec L., Leãoa M.H.M.R., 2007, Encapsulation of the Alpha-tocopherol in a 

Glassy Food Model Matrix, Materials Research 10 (1), 57-62. 

Goulaa A.M., Adamopoulos K.G., 2012, A method for pomegranate seed application in food industries: Seed 

oil encapsulation, Food and Bioproducts Processing 90 (4), 639-652. 

Marinho M.T., Bersot L.S., Nogueira A., Colman T.A.D., Schnitzler E., 2015, Antioxidant effect of dehydrated 

rosemary leaves in ripened semi-hard cheese: A study using coupled TG-DSC-FTIR (EGA), LWT-Food 

Science and Technology 63 (2), 1023-1028. 

Micic D.M., Ostojic S.B., Simonovic M.B., Krstic G., Pezo L.L., Simonovic B.R., 2015, Kinetics of blackberry 

and raspberry seed oils oxidation by DSC, Thermochimica Acta 601, 39-44. 

Mohd Fauzi N.A, Sarmidi M.R., Chua L.S., 2011, Metabolite profiling of heat treated whole palm oil extract, 

Journal of Applied Sciences 11 (13), 2376-2381. 

Tan N.A.H., Siddique B.M., Muhamad I.I., Mad Salleh L., Hassan N.D., 2013, Perah Oil: A Potential Substitute 

for Omega-3 Oils and Its Chemical Properties, International Journal of Biotechnology for Wellness 

Industries 2, 22-28. 

Velasco J., Dobarganes C., Márquez-Ruiz G., 2003, Variables affecting lipid oxidation in dried 

microencapsulated oils, Grasas y Aceites 54 (3), 304-314. 

X1,000 X25,000 X100,000 

1008

http://www.lifescienceglobal.com/home/cart?view=product&id=499
http://www.lifescienceglobal.com/home/cart?view=product&id=499