Chen Jiaxin, Zhao Jinhai, Kong Baohua, Chen Qian, Liu Qian, Liu Chengguo
College of Food Science, Northeast Agricultural University, Harbin 150030, China.
Institute for Advanced Technology, Heilongjiang Academy of Sciences, Harbin 150001, China.
Foods. 2021 Mar 11;10(3):593. doi: 10.3390/foods10030593.
The impact of typical primary or secondary lipid oxidation (LPO) products, selected as linoleic acid 13-hydroperoxide (13-HPODE) and malondialdehyde (MDA), on the structural modification of unadsorbed or adsorbed proteins in whey protein isolate (WPI)-stabilized oil-in-water (O/W) emulsions during storage up to 48 h at 37 °C in the dark was investigated. The results showed that either 13-HPODE and MDA could lead to structural modifications of unadsorbed or adsorbed proteins with a concentration-dependent manner and time relationship, respectively. Moreover, higher levels of MDA rendered a higher degree of oxidative modifications of WPI than 13-HPODE, indicated by the higher protein carbonyl contents and N'-formyl-L-kynurenine (NFK) and lower fluorescence intensity. Additionally, adsorbed proteins were more easily oxidized by LPO products than unadsorbed proteins. Overall, our results indicated that the formation of secondary LPO products and the protein position were crucial factors to increase the degree of oxidative modifications of WPI in O/W emulsion systems.
研究了在37℃黑暗条件下储存长达48小时期间，选定为亚油酸13-氢过氧化物（13-HPODE）和丙二醛（MDA）的典型一级或二级脂质氧化（LPO）产物对乳清蛋白分离物（WPI）稳定的水包油（O/W）乳液中未吸附或已吸附蛋白质结构修饰的影响。结果表明，13-HPODE和MDA均可分别导致未吸附或已吸附蛋白质的结构修饰，且呈浓度依赖性和时间关系。此外，较高水平的MDA对WPI的氧化修饰程度高于13-HPODE，这表现为较高的蛋白质羰基含量和N'-甲酰基-L-犬尿氨酸（NFK）以及较低的荧光强度。此外，已吸附的蛋白质比未吸附的蛋白质更容易被LPO产物氧化。总体而言，我们的结果表明，二级LPO产物的形成和蛋白质位置是增加O/W乳液体系中WPI氧化修饰程度的关键因素。
