云南小粒咖啡类黑精荧光矩阵光谱特征

Fluorescence Spectrum Characteristics of Melanoidins From Yunnan Arabica Coffee

本文以云南小粒咖啡为原料制备类黑精,采用三维荧光矩阵光谱分析技术(Three dimensional excitation emission matrix spectra,3D-EEMs)研究咖啡类黑精在不同温度、不同pH、不同光照及存放时间、不同浓度条件下的荧光光谱特征变化。结果表明:在10~80℃范围内云南小粒咖啡类黑精水溶液荧光强度与温度成反比;pH介于5~10之间的类黑精水溶液荧光强度较为稳定;避光存储的类黑精水溶液在60 min内荧光强度变化不显著(P>0.05),而光照时间增加会导致荧光强度显著下降(P<0.05);在浓度小于0.5 mg/mL时,类黑精水溶液荧光强度与浓度成正比,相关系数为0.9846;浓度大于10 mg/mL时会发生荧光猝灭,类黑精水溶液荧光强度与浓度不相关。本研究将为咖啡类黑精光谱特征的深入研究提供一定数据支持。

The melanoidins was prepared from Yunnan Arabica coffee.The 3D-EEMs were used to study the fluorescence characteristics of coffee melanoidins at different temperatures,pH,lighting conditions and at different concentrations.The results showed that the fluorescence intensity of aqueous solution of melanoidins was inversely proportional to the temperature in the range of 10~80℃.The fluorescence intensity of aqueous solutions of melanoidins with pH between 5 and 10 was stable.The fluorescence intensity of the melanoidins solution stored in dark did not change significantly within 60 min(P>0.05),while the increase of light time would lead to a significant decrease in fluorescence intensity(P<0.05).The fluorescence intensity of aqueous solutions of melanoidins was proportional to the concentration,and the correlation coefficient was 0.9846 when the concentration was less than 0.5 mg/mL.Fluorescence quenching occurs when the concentration was higher than 10 mg/mL,and the fluorescence intensity of aqueous solutions of melanoidins was not correlated with the concentration.This study would provide some data support for the further study of the spectral characteristics of coffee melanoidins.