贵州绿茶滋味分属性二次多项回归模型构建

Construction of quadratic multinomial regression model for Guizhou green tea taste attributes

【目的】通过分析贵州绿茶感官滋味特征和主要滋味成分含量及其Dot值,探究智能感官滋味特征属性及其相关化学物质,为建立贵州绿茶数字化评价体系提供理论依据。【方法】基于贵州5个茶叶主产区(遵义、铜仁、贵阳、黔南和六盘水)39个绿茶样品,经人工感官审评、智能感官审评和化学组分检测,结合二次多项式回归分析方法构建贵州绿茶滋味属性评价模型。【结果】醇度和鲜爽度是贵州绿茶的典型共有属性,不同产区贵州绿茶智能感官在鲜味和涩味上均有较高响应值,分别为12.85~18.21和13.15~26.77;苦味响应度较低,为3.98~8.44。不同产区贵州绿茶在滋味化学组分含量方面差异较小,其中水浸出物、总游离氨基酸和茶多酚平均质量分数分别为45.15%~46.63%、5.49%~6.46%和25.56%~27.63%,咖啡碱和绿原酸平均含量分别为35.85~41.63 mg/g和1.96~2.53 mg/g。构建了贵州绿茶滋味属性评价模型:Y(苦)=-0.3041+0.4189X_(6)+0.2182X^(2)_(2)+0.0015X_(1)X_(3)-0.0016X_(1)X_(4)-0.0885X_(2)X_(6)+0.6868X_(2)X_(7)-0.0434X_(6)X_(7);Y(涩)=21.9559-0.4562X_(6)+0.2728X^(2)_(2)-0.0196X_(1)X_(6)+0.1206X_(1)X_(7)+0.0192X_(3)X_(6)-0.0308X_(4)X_(7);Y(鲜)=13.3301+0.1096X^(2)_(2)-0.0037X_(1)X_(6)+0.0058X_(3)X_(6)-0.0013X_(4)X_(6)[X_(1)、X_(2)、X_(3)、X_(4)、X_(6)和X_(7)分别表示茶氨酸、谷氨酸、咖啡碱、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素没食子酸酯(ECG)和绿原酸];二次多项式回归模型显示,相关系数在0.8100以上,决定系数在0.6600以上,参考模型滋味强度鲜味为9.62~23.10、苦味为0.69~10.99、涩味为2.95~40.51。【结论】高水浸出物、高氨基酸、高咖啡碱和适中茶多酚形成贵州绿茶浓、醇、爽的滋味特征,根据3个模型能拼配出贵州绿茶滋味属性的最高强度和最低强度。

【Objective】To analyze the sensory taste characteristics,the content of main taste components and their Dot values of Guizhou green tea,and to explore the intelligent sensory taste characteristics and related chemical substances,and clarify the chemical contribution mechanism of the formation of the taste characteristics of Guizhou green tea,so as to provide theoretical reference for establishing a digital evaluation of Guizhou green tea.【Method】Based on 39 green tea samples from 5 main tea producing areas in Guizhou(Zunyi,Tongren,Guiyang,Qiannan,Liupanshui),artificial sensory evaluation,intelligent sensory evaluation,chemical composition detection were conducted,combined with quadratic multinomial regression model analysis method was used to construct the evaluation model of Guizhou green tea taste attributes.【Result】Mellowness and freshness were typical common attributes of Guizhou green tea.The intelligent sensory perception of Guizhou green tea from different producing areas had high responsivity values for umami and astringency,which were 12.85-18.21 and 13.15-26.77,respectively;bitterness responsivity were lower,ranging from 3.98 to 8.44.Guizhou green tea from different producing areas had little difference in the content of taste chemical components,among which the average mass fractions of water extract,total free amino acids and tea polyphenols were 45.15%-46.63%,5.49%-6.46%and 25.56%-27.63%,respectively.The average contents of caffeine and chlorogenic acid were 35.85-41.63 mg/g and 1.96-2.53 mg/g,respectively.An evaluation model for the taste attributes of Guizhou green tea was constructed:Y(bitter)=-0.3041+0.4189X_(6)+0.2182X_(2)~2+0.0015X_(1)X_(3)-0.0016X_(1)X_(4)-0.0885X_(2)X_(6)+0.6868X_(2)X_(7)-0.0434X_(6)X_(7);Y(astringent)=21.9559-0.4562X_(6)+0.2728X_(2)~2-0.0196X_(1)X_(6)+0.1206X_(1)X_(7)+0.0192X_(3)X_(6)-0.0308X_(4)X_(7);Y(fresh)=13.3301+0.1096X_(2)~2-0.0037X_(1)X_(6)+0.0058X_(3)X_(6)-0.0013X_(4)X_(6)(X_(1),X_(2),X_(3),X_(4),X_(6)and X_(7)respectively represented theanine,glutamic acid,caffeine,EGCG,GCG,chlorogenic acid).The quadratic polynomial regression model showed that the correlation coefficient was above 0.8100,the coefficient of determination was above 0.6600,and the taste intensity of the reference model was 9.62-23.10.The bitterness was 0.69-10.99,and the astringency was 2.95-40.51.【Conclusion】High water extract,high amino acid,high caffeine and moderate tea polyphenols form the thickness,mellow and refreshing taste characteristics of Guizhou green tea.According to the three models,the highest intensity and the lowest intensity of the taste attributes of Guizhou green tea can be combined.