State Key Laboratory of Food Science and Technology, Nanchang University, No. 235 Nanjing East Road, Nanchang 330047, China.
Guangxi Academy of Agricultural Sciences, Nanning 530007, China.
Food Res Int. 2023 Feb;164:112341. doi: 10.1016/j.foodres.2022.112341. Epub 2022 Dec 20.
Betanin (BN) is a kind of edible natural red pigment with a variety of biological activities, but the thermal instability of BN has critically restricted its application in food industry. In this study, complex plant protein (RP-PP) was constructed by rice protein (RP) and pea protein (PP) to study the thermal protection effect and protective mechanism on BN. Thermal degradation results indicated RP-PP significantly improved thermal protection effect, and the degradation rate of BN was decreased from 93.74 % to 56.48 % after heating at 80 ℃ for 60 min. The main interaction between RP-PP and BN was hydrophobic force based on the result of fluorescence spectroscopy, FTIR and molecular docking. In addition, a porous network structure of RP-PP was observed by SEM, and the pore structure gradually decreased at the presence of BN, which speculated BN was trapped in it. TEM observation showed that RP-PP gradually aggregated with the increasing BN concentration, leading to a significant increase in particle size and the formation of network structure. The BN acted as a bridge to the surrounding proteins in the aggregated complex and was encapsulated within it. The interaction and encapsulation may be the key reasons for the improved thermal stability of BN.
甜菜红（BN）是一种具有多种生物活性的可食用天然红色素，但 BN 的热不稳定性严重限制了其在食品工业中的应用。在本研究中，通过大米蛋白（RP）和豌豆蛋白（PP）构建了复合植物蛋白（RP-PP），以研究其对 BN 的热保护作用和保护机制。热降解结果表明，RP-PP 显著提高了 BN 的热保护效果，在 80℃加热 60min 后，BN 的降解率从 93.74%降低到 56.48%。荧光光谱、FTIR 和分子对接结果表明，RP-PP 和 BN 之间的主要相互作用是疏水相互作用。此外，通过 SEM 观察到 RP-PP 的多孔网络结构，并且随着 BN 的存在，孔结构逐渐减少，推测 BN 被捕获在其中。TEM 观察表明，随着 BN 浓度的增加，RP-PP 逐渐聚集，导致粒径显著增大并形成网络结构。BN 作为桥接作用将周围的蛋白质连接在聚集的复合物中并将其包裹在内。这种相互作用和包裹可能是 BN 热稳定性提高的关键原因。
