基于滋味和香气成分结合化学计量法鉴别不同贮藏年份的康砖茶

本研究以不同贮藏年份康砖茶为试验材料，测定其主要的滋味成分和香气成分，初步明晰贮藏过程中滋味成分和香气成分的变化规律，通过化学计量学方法，客观地鉴别不同贮藏年份康砖茶的滋味特征和香气轮廓。结果表明：康砖茶滋味和香气对贮藏时间有明显的响应。茶多酚、儿茶素组分、没食子酸、咖啡碱、可溶性总糖和和葡萄糖含量在贮藏期1~10年间降低，在之后的10~30年间增加。茶褐素和麦芽糖含量在贮藏期1~30年间显著增加（p<0.05）。构成香气轮廓的特征挥发性成分数量先减少后增加，酯类和杂环类逐渐取代不饱和醛类、醇类和酚类成为康砖茶的重要赋香成分。基于贮藏期的康砖茶滋味特征和香气轮廓的变化规律，滋味特征分为1~6年、10~15年和22~30年；香气轮廓分为1~6年、10~22年和25~30年。贮藏期10年是滋味特征和香气轮廓从新茶向陈年老茶转变的转折点。因此，基于滋味成分和香气成分结合化学计量学对不同贮藏年份康砖茶的品质特征进行鉴别是可行的，滋味特征和香气轮廓的变化规律可作为康砖茶价值评价的重要依据。

Chemometric Discrimination of Different Aged Kang Brick Teas based on Tasty and Aroma Compounds

To explore the change patterns of tasty and volatile components during storage, chemical components and volatiles were determined for different aged Kang brick teas selected as the experimental materials. The different aged Kang brick teas were differentiated based on chemical components and volatiles combined with chemometrics algorithms. Results showed that the content of components including tea polyphenols, catechins, gallic acid, caffeine, total soluble sugar and glucose, decreased during the first 10-year storage, but increased during the next storage period of 20 years. The contents of maltose and theabrownin significantly increased during the whole 30-year storage. The amount of characteristic volatile components gradually decreased, and then increased during this period. Esters and heterocyclics gradually replaced unsaturated aldehydes, alcohols and phenols as important aroma components of Kang brick teas. According to the storage periods of Kang brick teas, the taste characteristics were divided into three patterns, including the period of 1~6 years, the period of 10~15 years and the period of 22~30 years. The stage of the aroma profile included the period of 1~6 years, the period of 10~22 years and the period of 25~30 years. Therefore, the 10th year during the storage was supposed to be the turning point in the conversion of the tasty and aroma from new teas to aged teas. It was feasible to employ chemometrics coupled with biochemical components and volatiles to identify aged Kang brisk tea. Both of the flavor characteristics and aroma profile could be a reference to estimate the economic value of Kang brisk tea.