Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils

The seeds from the Shorea genus are popular among Sarawak locals and known as ‘Buah Engkabang’. However, the information on Shorea seed and oil is still scarce. Thus, the objectives of this study were to collect the Shorea oilseeds (Shorea macrophylla, Shorea palembanica, Shorea stenoptera and Shore...

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Main Author:	Sahlinah, Abdul Rakman
Format:	Thesis
Language:	English
Published:	2022
Subjects:	QD Chemistry
Online Access:	http://ir.unimas.my/id/eprint/39759/1/Sahlinah.pdf
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spelling	my-unimas-ir.397592023-07-04T08:19:40Z Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils 2022 Sahlinah, Abdul Rakman QD Chemistry The seeds from the Shorea genus are popular among Sarawak locals and known as ‘Buah Engkabang’. However, the information on Shorea seed and oil is still scarce. Thus, the objectives of this study were to collect the Shorea oilseeds (Shorea macrophylla, Shorea palembanica, Shorea stenoptera and Shorea pinanga) and then to gather their proximate, minerals and anti-nutritive factors data, as well as the effects of extraction methods and oil refining on the physical and chemical properties, fatty acid composition, antioxidant activity and total phenolic content (TPC).The proximate composition are significantly different (p<0.05) between the seeds of S. macrophylla (moisture: 21.47%; ash: 0.67%; total lipid: 41.37%; total fibre: 15.67%; total carbohydrate: 79.44%), S. palembanica (moisture: 27.25%; ash: 1.98%; total lipid: 49.06%; total fibre: 7.72%; total carbohydrate: 82.37%), S. stenoptera (moisture: 16.06%; ash: 4.42%; total lipid: 38.80%; total fibre: 30.687%; total carbohydrate: 66.45%) and S. pinanga (moisture: 35.56%; ash: 2.23%; total lipid: 46.91%; total fibre: 8.09%; total carbohydrate: 79.64%). K and Zn are the predominant macro and microminerals, respectively. The evaluation of antinutrients disclosed low phytate but high oxalate content in S. macrophylla (0.29% and 1.91%), S. palembanica (0.29% and 2.43%), S. stenoptera (0.09% and 2.65%) and S. pinanga (0.06% and 3.61%). The mechanical extraction method is the choice of Shorea seed oil extraction because the mechanically extracted S. palembanica oil (cis-MUFAs: 34.49%; acid value: 3.47 mg NaOH/kg; peroxide value: 10.62 meq O2/kg; TPC: 2.49 mg GAE/kg) is of higher quality than the Soxhlet extracted oil (cis-MUFAs: 34.23%; acid value: 8.00 mg NaOH/kg; peroxide value: 14.58 meq O2/kg; TPC: 0.68 mg GAE/kg) (p<0.05). The fatty acid composition in Shorea oils dominantly consists of stearic, oleic and palmitic acids similar to the fatty acid profile of cocoa butter, indicating the potential of Shorea seed oils to be utilised in the chocolate industry. Point-Biserial Correlation (rpb) was used to investigate the impact of oil refining on physical and chemical characteristics, fatty acid composition, antioxidant activity and TPC. A significant negative correlation between oil refining and acid and peroxide values (rpb= -1.00, p<0.05) demonstrates that oil refining effectively reduces acid and peroxide values, resulting in improved oil quality. The refining process has no significant impact on the fatty acid content according to oil analysis using Gas Chromatography-Mass Spectrometer (GC-MS) and Attenuated Total Reflectance-Fourier Transform Infrared Spectrometer (ATR-FTIR) (p>0.05). However, there is an increase in essential fatty acid of linoleic acid in S. macrophylla oil from undetected to 1.01% and S. pinanga oil from 0.34% to 0.41% with the elimination of harmful fatty acids such as elaidic and erucic acids in S. macrophylla oil. Refining increased the antioxidant activity of S. palembanica (crude: 813.02 μg/mL; refined: 239.88 μg/mL) and S. pinanga (crude: 214.11 μg/mL; refined: 56.77 μg/mL) oils, whilst refining S. macrophylla (crude: 244.55 μg/m; refined: 471.36 μg/mL) and S. stenoptera (crude: 152.22 μg/mL; refined: 249.49 μg/mL) oils reduced their antioxidant activity. Universiti Malaysia Sarawak 2022 Thesis http://ir.unimas.my/id/eprint/39759/ http://ir.unimas.my/id/eprint/39759/1/Sahlinah.pdf text en validuser masters Faculty of Resource Science and Technology Chemistry
institution	Universiti Malaysia Sarawak
collection	UNIMAS Institutional Repository
language	English
topic	QD Chemistry
spellingShingle	QD Chemistry Sahlinah, Abdul Rakman Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils
description	The seeds from the Shorea genus are popular among Sarawak locals and known as ‘Buah Engkabang’. However, the information on Shorea seed and oil is still scarce. Thus, the objectives of this study were to collect the Shorea oilseeds (Shorea macrophylla, Shorea palembanica, Shorea stenoptera and Shorea pinanga) and then to gather their proximate, minerals and anti-nutritive factors data, as well as the effects of extraction methods and oil refining on the physical and chemical properties, fatty acid composition, antioxidant activity and total phenolic content (TPC).The proximate composition are significantly different (p<0.05) between the seeds of S. macrophylla (moisture: 21.47%; ash: 0.67%; total lipid: 41.37%; total fibre: 15.67%; total carbohydrate: 79.44%), S. palembanica (moisture: 27.25%; ash: 1.98%; total lipid: 49.06%; total fibre: 7.72%; total carbohydrate: 82.37%), S. stenoptera (moisture: 16.06%; ash: 4.42%; total lipid: 38.80%; total fibre: 30.687%; total carbohydrate: 66.45%) and S. pinanga (moisture: 35.56%; ash: 2.23%; total lipid: 46.91%; total fibre: 8.09%; total carbohydrate: 79.64%). K and Zn are the predominant macro and microminerals, respectively. The evaluation of antinutrients disclosed low phytate but high oxalate content in S. macrophylla (0.29% and 1.91%), S. palembanica (0.29% and 2.43%), S. stenoptera (0.09% and 2.65%) and S. pinanga (0.06% and 3.61%). The mechanical extraction method is the choice of Shorea seed oil extraction because the mechanically extracted S. palembanica oil (cis-MUFAs: 34.49%; acid value: 3.47 mg NaOH/kg; peroxide value: 10.62 meq O2/kg; TPC: 2.49 mg GAE/kg) is of higher quality than the Soxhlet extracted oil (cis-MUFAs: 34.23%; acid value: 8.00 mg NaOH/kg; peroxide value: 14.58 meq O2/kg; TPC: 0.68 mg GAE/kg) (p<0.05). The fatty acid composition in Shorea oils dominantly consists of stearic, oleic and palmitic acids similar to the fatty acid profile of cocoa butter, indicating the potential of Shorea seed oils to be utilised in the chocolate industry. Point-Biserial Correlation (rpb) was used to investigate the impact of oil refining on physical and chemical characteristics, fatty acid composition, antioxidant activity and TPC. A significant negative correlation between oil refining and acid and peroxide values (rpb= -1.00, p<0.05) demonstrates that oil refining effectively reduces acid and peroxide values, resulting in improved oil quality. The refining process has no significant impact on the fatty acid content according to oil analysis using Gas Chromatography-Mass Spectrometer (GC-MS) and Attenuated Total Reflectance-Fourier Transform Infrared Spectrometer (ATR-FTIR) (p>0.05). However, there is an increase in essential fatty acid of linoleic acid in S. macrophylla oil from undetected to 1.01% and S. pinanga oil from 0.34% to 0.41% with the elimination of harmful fatty acids such as elaidic and erucic acids in S. macrophylla oil. Refining increased the antioxidant activity of S. palembanica (crude: 813.02 μg/mL; refined: 239.88 μg/mL) and S. pinanga (crude: 214.11 μg/mL; refined: 56.77 μg/mL) oils, whilst refining S. macrophylla (crude: 244.55 μg/m; refined: 471.36 μg/mL) and S. stenoptera (crude: 152.22 μg/mL; refined: 249.49 μg/mL) oils reduced their antioxidant activity.
format	Thesis
qualification_level	Master's degree
author	Sahlinah, Abdul Rakman
author_facet	Sahlinah, Abdul Rakman
author_sort	Sahlinah, Abdul Rakman
title	Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils
title_short	Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils
title_full	Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils
title_fullStr	Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils
title_full_unstemmed	Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils
title_sort	evaluation of physicochemical properties, fatty acid composition and antioxidant activity of engkabang (shorea spp.) seed oils
granting_institution	Faculty of Resource Science and Technology
granting_department	Chemistry
publishDate	2022
url	http://ir.unimas.my/id/eprint/39759/1/Sahlinah.pdf
_version_	1783728514512453632

Evaluation of Physicochemical Properties, Fatty Acid Composition and Antioxidant Activity of Engkabang (Shorea spp.) Seed Oils

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