基于电子舌的3种氨基酸单体呈味特性研究

Flavor Characteristics of Three Amino Acid Monomers Based on Electronic Tongue

氨基酸是茶汤鲜味的主体贡献物质。为客观评价茶叶中主要氨基酸类物质呈味特性,文章从单体出发,以茶氨酸、谷氨酸、天冬氨酸为对象,结合电子舌检测技术,探究不同pH值对3种氨基酸呈味特性影响,及其不同浓度下的呈味强度、阈值和相互作用关系。结果表明:随着pH值的增加,茶氨酸、谷氨酸、天冬氨酸呈鲜味逐渐增强,在pH6~7时,鲜味增幅较为稳定,接近最大值。随着浓度增加,茶氨酸鲜味逐渐增强,谷氨酸和天冬氨酸酸味逐渐增加,而鲜味反而降低,3种氨基酸单体呈味浓度-强度函数良好,R^(2)值均大于0.995;茶氨酸、谷氨酸、天冬氨酸鲜味阈值分别为4、0.04、0.15 mg/mL,且三者相互间呈协同增鲜效应,低浓度氨基酸增鲜效果强于高浓度,谷氨酸的增鲜效果强于茶氨酸和天冬氨酸。研究结果可为氨基酸类物质呈味特性提供参考。

Amino acids are the main contributors to the freshness of tea water.In order to objectively evaluate the flavour characteristics of the main amino acids in tea,this study was conducted to investigate the effects of different pH values on the flavour characteristics of the three amino acids,and their flavour intensity,threshold and interactions at different concentrations,taking theanine,glutamic acid and aspartic acid as the subjects from the monomers and combining with electronic tongue detection techniques.The results showed that the theanine,glutamic acid and aspartic acid showed a gradual increase in freshness as the pH increased,with a more stable increase in freshness between pH 6 and 7,close to the maximum value.As the concentration increased,the freshness of theanine gradually increased,the acidity of glutamic acid and aspartic acid gradually increased,while the freshness decreased,and the three amino acid monomers presented a good concentration-intensity function with R^(2) values greater than 0.995.The freshness thresholds of theanine,glutamic acid and aspartic acid were 4 mg/mL,0.04 mg/mL and 0.15 mg/mL respectively,and the three showed a synergistic effect on each other,with low concentrations as the substrate amino acids having a stronger freshness effect than high concentrations,and glutamic acid having a stronger freshness effect than theanine and aspartic acid.This study can provide a reference for the flavour characteristics of amino acid substances.