微波与超声处理对花青素-多酚固态与液态体系色泽的影响

Effect of Microwave and Ultrasonic Treatment on the Color of Anthocyanin-Polyphenol Solid and Liquid Systems

花青素与多酚相互作用具有改善呈色的作用,而其在固态与液态体系中的呈色特性及色泽稳定性还不明确。本实验采用微波与超声处理花青素-多酚液态和固态模拟体系,通过分析处理后花青素-多酚液态和固态体系的表观色泽、光谱特性及多酚、花青素组成含量变化,初步阐释微波与超声处理对花青素-多酚相互作用呈色的影响机制。结果表明,经微波和超声处理后,固态体系L*值升高,b*值降低,a*值无明显变化;液态体系光谱发生红移,说明分子振动、空化效应对光谱吸收影响大;固态和液态体系中总花青素含量提高,多酚含量降低,发生新绿原酸转化为绿原酸反应。多变量统计分析结果显示,不同条件微波与超声处理体系的呈色特性差异显著,该差异主要由体系中不同含量原儿茶酸、儿茶素和总花青素引起。微波功率为30 W或超声时间为90 min处理的花青素-多酚固态体系和液态体系L*值、a*值、b*值、最大吸收波长处的吸光度、总花青素和多酚含量较高,对体系呈色稳定性贡献较大。综上,微波与超声处理可为提升天然花青素稳定性提供新的技术手段。

The interaction between anthocyanins and polyphenols can improve color properties of anthocyanins,while the color properties and stability of anthocyanins in solid and liquid systems containing polyphenols are not yet clear.In this paper,in order to clarify the effect and underlying mechanism of microwave and ultrasonic treatment on the color of anthocyanin-polyphenol complexes in the solid and liquid states,the changes in the apparent color,spectral characteristics and anthocyanin composition and contents were examined after the treatments.The results showed that after either treatment,L*value increased,b*value decreased,and a*value did not change remarkably in the solid system.The liquid system showed a remarkable red shift in the absorption spectra,indicating that molecular vibration and cavitation effect have a great impact on the spectral absorption.Meanwhile,in both systems,the content of total anthocyanins increased,together with a decrease in polyphenol content and the conversion of neochlorogenic acid to chlorogenic acid.Multivariate statistical analysis showed significant differences in color properties among the complex systems subjected to microwave and ultrasonic treatment under different conditions,which may be mainly caused by the differences in the contents of protocatechuic acid,catechins and total anthocyanins.For both liquid and solid systems,L*,a*and b*values,absorbance at the maximum absorption wavelength,the contents of total anthocyanins and polyphenols were higher after microwave treatment at 30 W or ultrasonic treatment for 90 min as compared to other treatment conditions,greatly contributing to the color stability of the systems.In summary,microwave and ultrasonic treatments are alternative techniques for improving the stability of anthocyanins.