Chen Xi, Han Xue, Chen Mianhong, Lu Xuli, Zhou Wei, Li Ruyi
School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China; Key Laboratory of Tropical Crop Products Processing of Ministry of Agriculture and Rural Affairs, Agricultural Products Processing Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang 524001, China.
School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
Int J Biol Macromol. 2025 Apr;304(Pt 1):140481. doi: 10.1016/j.ijbiomac.2025.140481. Epub 2025 Jan 29.
This study explored the non-covalent interactions between oat protein isolate (OPI) and two tannic compounds-proanthocyanidins (PA) and tannic acid (TA)-and examined their impact on the structural and digestive properties of oat proteins. The combination of OPI with tannic compounds formed granular complexes with particle sizes ranging from 126 to 240 nm and zeta potentials between -35 and -44 mV. Compared to OPI alone, the α-helix and β-turn contents decreased, while the β-sheet and random coil contents increased in both OPI-tannin complexes. Fluorescence spectra analysis indicated that hydrogen bonding was the main interaction force in OPI-PA complexes, while OPI and TA were primarily bound by hydrophobic interactions. The simulated digestion analysis showed that the protein digestibility was delayed in the OPI-tannin complexes, likely due to the inhibition of digestive enzyme activity by tannic compounds, which slowed OPI digestibility. Additionally, the oxidation resistance of the OPI-tannin complexes significantly improved after in vitro digestion, indicating that the non-covalent complexes provided superior protection for the tannic compounds. These findings offer theoretical support for the design and utilization of oat- and tannin-rich foods.
本研究探讨了燕麦分离蛋白（OPI）与两种单宁化合物——原花青素（PA）和单宁酸（TA）之间的非共价相互作用，并研究了它们对燕麦蛋白结构和消化特性的影响。OPI与单宁化合物结合形成了粒径在126至240 nm之间、ζ电位在-35至-44 mV之间的颗粒状复合物。与单独的OPI相比，两种OPI-单宁复合物中的α-螺旋和β-转角含量降低，而β-折叠和无规卷曲含量增加。荧光光谱分析表明，氢键是OPI-PA复合物中的主要相互作用力，而OPI与TA主要通过疏水相互作用结合。模拟消化分析表明，OPI-单宁复合物中的蛋白质消化率延迟，这可能是由于单宁化合物抑制了消化酶活性，从而减缓了OPI的消化率。此外，OPI-单宁复合物在体外消化后抗氧化性显著提高，表明非共价复合物为单宁化合物提供了更好的保护。这些发现为富含燕麦和单宁的食品的设计和利用提供了理论支持。
