Manochai Tanaporn, Kamthai Suthaphat, Siriwoharn Thanyaporn
Division of Food Science and Technology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand.
Division of Packaging Technology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand.
Foods. 2025 Jul 24;14(15):2596. doi: 10.3390/foods14152596.
Incorporating health-promoting resveratrol into food products is challenging, primarily due to its poor solubility. Covalent conjugation is a promising, low-energy, and environmentally friendly strategy to overcome this limitation. This study compared the effectiveness of free radical grafting and alkaline methods for covalently conjugating whey protein isolate (WPI) with resveratrol. Conjugates were evaluated for molecular weight, structural characteristics, functional properties, and antioxidant activities. Both methods yielded conjugates with enhanced solubility relative to native resveratrol, with fold increases from 7.6 to 21.7 for the free radical grafting and from 8.1 to 23.6 for the alkaline method. Conjugates prepared via free radical grafting exhibited greater increases in molecular weight (10-100 kDa range), higher resveratrol incorporation (up to 17.6%), and superior functional properties compared to the alkaline conjugates ( < 0.05). Specifically, emulsifying activity, foaming capacity, and foaming stability improved by up to 64.7%, 45.8%, and 220.9%, respectively, compared to WPI. The antioxidant activities of the free radical grafting conjugates were 1.3- to 3.6-fold higher than those of alkaline conjugates. These findings highlight free radical grafting of WPI as a promising approach for incorporating resveratrol and improving the functionality of protein-based ingredients in functional food products.
将具有健康促进作用的白藜芦醇添加到食品中具有挑战性，主要是因为其溶解性较差。共价结合是一种有前景的、低能耗且环保的策略，可克服这一限制。本研究比较了自由基接枝法和碱性法将乳清分离蛋白（WPI）与白藜芦醇共价结合的效果。对接合物的分子量、结构特征、功能特性和抗氧化活性进行了评估。相对于天然白藜芦醇，两种方法得到的结合物溶解度均有所提高，自由基接枝法的溶解度提高了7.6至21.7倍，碱性法提高了8.1至23.6倍。与碱性结合物相比（<0.05），通过自由基接枝制备的结合物分子量增加更大（10 - 100 kDa范围），白藜芦醇结合量更高（高达17.6%），功能特性更优。具体而言，与WPI相比，乳化活性、发泡能力和发泡稳定性分别提高了64.7%、45.8%和220.9%。自由基接枝结合物的抗氧化活性比碱性结合物高1.3至
