The Engineering Research Center for High-Valued Utilization of Fruit Resources in Western China, Ministry of Education; National Research & Development Center of Apple Processing Technology; College of Food Engineering and Nutritional Science, Shaanxi Normal University, 620 West Changan Avenue, Xian, Shaanxi 710119, PR China.
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xian, Shaanxi 710127, PR China.
Food Res Int. 2022 Aug;158:111541. doi: 10.1016/j.foodres.2022.111541. Epub 2022 Jun 22.
Lipid-protein co-oxidation often causes nutrition loss, texture changes, and shortened shelf-life of emulsions. In this study, resveratrol significantly prevented lipid-protein co-oxidation in sodium caseinate (NaCas)-walnut oil emulsions, and the underlying mechanisms were explored in physical and chemical aspects. NaCas-walnut oil emulsions stabilized by resveratrol exhibited excellent physical stability at 55 °C for 12 days or at room temperature for 10 months due to forming a stable interfacial layer composed of resveratrol-modified NaCas. Furthermore, resveratrol binding caused NaCas structure's partial unfolding and a ∼ 8% increase in hydrophobicity, in turn enhancing NaCas' emulsification properties and electrostatic repulsion. Besides, more than 90% of resveratrol was loaded at the interface and enhanced NaCas' Fe chelating, DPPH scavenging abilities, and O quenching by ∼ 22.6%, 5.26 times, and 31.84%, respectively. Simultaneously, resveratrol significantly improved NaCas' oxidative stability, as reflected by the decrease in adsorbed NaCas' intrinsic fluorescence loss and protein carbonyls gain by ∼ 30% and 37%, respectively. Simultaneously, lipid hydroperoxides and TBARS were reduced by ∼ 30% and 20% in the NaCas-walnut oil emulsions containing 6 mM resveratrol than the control. Our findings contribute to further understanding of the possible interaction among lipid, protein, polyphenols, and their oxidative products at the oil-water interface, minimizing lipid-protein co-oxidation and extending functional oils' shelf life. Finally, walnut oil emulsions with high physical and oxidative stabilities using resveratrol were prepared, further broadening resveratrol's application in the food industry.
脂-蛋白协同氧化通常会导致营养成分损失、质地变化和乳液保质期缩短。在这项研究中，白藜芦醇显著抑制了乳清蛋白-核桃油乳液的脂-蛋白协同氧化，从物理和化学方面探讨了其潜在机制。由于形成了由白藜芦醇修饰的乳清蛋白稳定的界面层，白藜芦醇稳定的乳清蛋白-核桃油乳液在 55°C 下稳定 12 天或在室温下稳定 10 个月。此外，白藜芦醇结合导致乳清蛋白结构部分展开，疏水性增加约 8%，进而增强乳清蛋白的乳化性能和静电排斥。此外，超过 90%的白藜芦醇被加载到界面上，并增强乳清蛋白的 Fe 螯合、DPPH 清除能力和 O 猝灭能力，分别增加了约 22.6%、5.26 倍和 31.84%。同时，白藜芦醇显著提高了乳清蛋白的氧化稳定性，表现为吸附的乳清蛋白固有荧光损失减少约 30%，蛋白质羰基含量增加约 37%。同时，含有 6mM 白藜芦醇的乳清蛋白-核桃油乳液中的脂质氢过氧化物和 TBARS 分别减少约 30%和 20%，比对照样品少。我们的研究结果有助于进一步了解油-水界面处脂质、蛋白质、多酚及其氧化产物之间可能的相互作用，最大限度地减少脂-蛋白协同氧化，延长功能性油脂的保质期。最后，利用白藜芦醇制备了具有高物理和氧化稳定性的核桃油乳液，进一步拓宽了白藜芦醇在食品工业中的应用。
