Ren Shuai, Giusti M Monica
Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Rd, Columbus, OH 43210-1007, USA.
Foods. 2021 Feb 3;10(2):310. doi: 10.3390/foods10020310.
The color stability of anthocyanins was shown to improve with addition of whey proteins (WP). The goal of this study was to investigate the binding mechanisms of purple corn, grape and black carrot anthocyanin extracts to native and preheated WP (40-80 °C, 3.6 μM) at a pH of 3 using fluorescence quenching spectroscopy. The fluorescence spectra were collected with an excitation wavelength of 280 nm at 25 °C, 35 °C and 45 °C. The quenching data were analyzed by using the Stern-Volmer equation. The fluorescence intensity of WP decreased (up to 73%) and its λ increased (by ~5 nm) with increasing anthocyanin concentration (0-100 μM). The quenching data showed that the interaction between anthocyanin extracts and WP was a static quenching process. Thermodynamic analysis showed their binding was mainly through hydrophobic interactions. Their binding affinity was higher for preheated WP than native WP and decreased gradually with increasing preheating temperature. Black carrot anthocyanin extract had the lowest binding affinity with WP, likely due to the larger molecular structure. These results help better understand the protection mechanism of native and preheated WP on anthocyanin color stability, expanding the application of anthocyanins as food colorants that better withstand processing and storage.
研究表明，添加乳清蛋白（WP）可提高花青素的颜色稳定性。本研究的目的是利用荧光猝灭光谱法，在pH值为3的条件下，研究紫玉米、葡萄和黑胡萝卜花青素提取物与天然和预热WP（40 - 80°C，3.6 μM）的结合机制。在25°C、35°C和45°C下，以280 nm的激发波长收集荧光光谱。使用Stern-Volmer方程分析猝灭数据。随着花青素浓度（0 - 100 μM）的增加，WP的荧光强度降低（高达73%），其波长增加（约5 nm）。猝灭数据表明，花青素提取物与WP之间的相互作用是一个静态猝灭过程。热力学分析表明，它们的结合主要通过疏水相互作用。它们对预热WP的结合亲和力高于天然WP，并且随着预热温度的升高而逐渐降低。黑胡萝卜花青素提取物与WP的结合亲和力最低，可能是由于其分子结构较大。这些结果有助于更好地理解天然和预热WP对花青素颜色稳定性的保护机制，扩大花青素作为更能耐受加工和储存的食用色素的应用。
