College of Food Science and Engineering, Northwest A&F University, Yangling 712100, Shaanxi, China.
Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA.
Ultrason Sonochem. 2022 Sep;89:106110. doi: 10.1016/j.ultsonch.2022.106110. Epub 2022 Aug 1.
The aim of this study was to prepare lactoferrin-epigallocatechin-3-gallate (LF-EGCG) conjugates and to determine their ability to protect emulsified algal oil against aggregation and oxidation. LF-EGCG conjugates were formed using an ultrasound-assisted alkaline treatment. The ultrasonic treatment significantly improved the grafting efficiency of LF and EGCG and shortened the reaction time from 24 h to 40 min. Fourier transform infrared spectroscopy and circular dichroism spectroscopy analyses showed that the covalent/non-covalent complexes could be formed between LF and EGCG, with the CO and CN groups playing an important role. The formation of the conjugates reduced the α-helix content and increased the random coil content of the LF. Moreover, the antioxidant activity of LF was significantly enhanced after conjugation with EGCG. LF-EGCG conjugates as emulsifiers were better at inhibiting oil droplet aggregation and oxidation than LF alone. This study demonstrates that ultrasound-assisted formation of protein-polyphenol conjugates can enhance the functional properties of the proteins, thereby extending their application as functional ingredients in nutritionally fortified foods.
本研究旨在制备乳铁蛋白-表没食子儿茶素没食子酸酯（LF-EGCG）缀合物，并测定其保护乳化藻油防止聚集和氧化的能力。LF-EGCG 缀合物是通过超声辅助碱性处理形成的。超声处理显著提高了 LF 和 EGCG 的接枝效率，并将反应时间从 24 小时缩短至 40 分钟。傅里叶变换红外光谱和圆二色光谱分析表明，LF 和 EGCG 之间可以形成共价/非共价复合物，其中 CO 和 CN 基团起着重要作用。形成缀合物后，LF 的α-螺旋含量降低，无规卷曲含量增加。此外，LF 与 EGCG 缀合后其抗氧化活性显著增强。作为乳化剂的 LF-EGCG 缀合物比 LF 更能抑制油滴聚集和氧化。本研究表明，超声辅助形成蛋白质-多酚缀合物可以增强蛋白质的功能特性，从而将其作为营养强化食品中的功能性成分得到更广泛的应用。
