Comparison of lipid degradation in raw and infrared stabilized rice bran and rice bran oil: matrix effect
- PDF / 756,251 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 56 Downloads / 185 Views
ORIGINAL PAPER
Comparison of lipid degradation in raw and infrared stabilized rice bran and rice bran oil: matrix effect Neşe Yılmaz Tuncel1 · Fatma Yılmaz Korkmaz2 Received: 6 October 2019 / Accepted: 13 October 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract In this study, freshly milled rice bran samples were stabilized with short-wave (peak wavelength 1.0–1.4 µm) and mediumwave (peak wavelength 2.4–2.7 µm) infrared (IR) emitters at the same conditions (IR power and process time). Half of the unprocessed and IR stabilized samples were stored in bran form and the other half was extracted with hexane and stored in the form of crude rice bran oil for 6 months at room temperature (25 °C). All samples were analyzed for free fatty acids (FFA), peroxide value (PV), conjugated dienoic acids, p-Anisidine value (p-AnV), and tocopherol and gamma-oryzanol contents throughout the storage. As a conclusion, it was found that hydrolytic lipid degradation occurs more likely in samples stored in bran form; however, samples stored in oil form was more prone to oxidative degradation. After 6 months of storage at room temperature, FFA content of the unprocessed (control) samples increased from 2 to 68.27% and 17.94% when stored in bran and oil matrix, respectively. Additionally FFA content of the IR stabilized samples which were stored in bran matrix was also higher than their counterparts stored in oil matrix. Medium-wave IR stabilization was more effective in retarding FFA increase when compared to short-wave IR stabilization. Although PV of all samples was below 10 meq oxygen/kg oil, PV and p-AnV of the samples stored in oil matrix was significantly higher than that of the samples stored in bran matrix (p < 0.05). Furthermore, storage in oil form resulted in higher loss in total tocopherol and γ-oryzanol compared to storage in bran form (p < 0.05). Keywords Rice bran · Rice bran oil · Stabilization · Infrared · Rancidity · Oxidation
Introduction Rice bran, one of the by-products of paddy milling process, is the outer layer of the brown rice. Although the percentage and composition of rice bran vary according to the rice variety, type of milling system, degree of milling and pretreatments employed before milling, it basically comprises of pericarp, aleurone, subaleurone, seed coat, germ and minor amounts of endosperm and constitutes about 10% of rough Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11694-020-00709-5) contains supplementary material, which is available to authorized users. * Neşe Yılmaz Tuncel [email protected] 1
Faculty of Applied Sciences, Department of Food Technology, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
Faculty of Engineering, Department of Food Engineering, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
2
rice grain. Rice bran comprises of 12–22% oil, 10–15% moisture, 11–17% protein, and 8–17% ash [1]. Rice bran contains many bioactive components such as unsaturated fatty acids, γ-o
Data Loading...
