導讀

近日，浙江大學徐平教授所在研究團隊在《Food Research International》發表了一項最新研究，深入探討了‘白葉1號’紅茶的風味物質基礎和形成機制。研究通過聚焦于‘白葉1號’這一高氨基酸含量的茶樹品種，通過感官評價和代謝組學分析，深入探討了其制成紅茶（BYBT）的風味特征及其隨季節的變化規律。研究發現，BYBT具有獨特的橙紅色湯色、甜薯或蜂蜜香氣，以及甜、鮮、清淡的口感。通過揮發物分析，鑒定出110種特征性揮發物，確定了來源于脂質氧化和類胡蘿卜素降解的29種揮發性代謝物（包括具有甜香的β-紫羅蘭酮）可能是其甜香的關鍵貢獻化合物。此外，研究還發現，不同季節的‘白葉1號’紅茶在揮發物組成上存在顯著差異，其中春季紅茶的甜香更為濃郁，這與其較高的β-羅勒烯、香葉醇、檸檬醛含量有關。BYBT中氨基酸及糖類含量較高，而多酚類的含量較低，對其鮮味和甜味的滋味特點有重要影響。該研究通過深入解析不同季節紅茶的風味差異，為開發新型紅茶產品及其衍生品提供了科學依據，同時也為茶葉加工技術的創新和紅茶品質的提升提供了重要參考。

英文摘要

Black tea flavor is predominantly shaped by the internal composition of the materials utilized, and black teas produced from high-polyphenol varieties is typically characterized by a stronger, bitter, astringent taste with a low aroma intensity. Therefore, understanding the flavor profile and material basis of black tea produced from high-amino acids tea plants may be helpful to enhance flavor and innovate black tea products. Here, by sensory evaluation and metabolomics analysis, it was found that the typical flavor of 'Baiye 1' black tea (BYBT) was orange-red solution color, a sweet potato-like or sweet honey-like aroma, and a sweet, umami, and light taste. A total of 110 characteristic volatiles of BYBT were identified, among which 29 metabolites, including β-ionone with a sweet aroma, may be considered the key compounds responsible for the sweet aroma. The geraniol, cis-3-hexenyl isovalerate, and n-valeric acid cis-3-hexenyl were key volatiles that distinguish different seasons. Additionally, 7 volatiles, including β-ocimene, geraniol, citral, were the crucial metabolites responsible for the stronger sweet or honey aroma of BYBT in spring. The lower tea polyphenols and the higher amino acids and sugars shaped the BYBT profile with distinct umami and sweetness, as well as a light taste. Amino acids, catechins and their derivatives were the most significantly affected by seasonal variations in BYBT, and were also responsible for the differences in taste and color quality observed between samples with different seasons. The findings of this study provided a scientific foundation for the development of novel black tea products or derivatives thereof.

代表性圖片

▲摘要圖

▲ 不同季節的 ‘白葉1號’紅茶（BYBT）的感官品質分析。（A）不同BYBT的干茶、茶湯和葉底圖片；（B）不同BYBT的感官評分；（C）顏色參數，特別是不同BYBTs茶湯的H、S、L值；（D）不同BYBT電子舌數據的主成分分析；（E）電子舌數據雷達圖

▲ 不同季節BYBT的香氣和揮發性代謝物特征。（A）三個樣品中揮發物分類含量圓環圖；（B）主成分分析；（C）SP-BT、SU-BT和AU-BT的Venn圖；（D）ROAV≥1的揮發性化合物數量圓環圖；（E）三個季節紅茶樣品中不同揮發性化合物的含量；（F）三個季節紅茶樣品中ROAV>1的共有揮發性化合物風味雷達圖

▲ BYBT中ROAV＞1的前30種揮發性代謝物的結構、名稱、風味特征、ROAV值和形成途徑

▲ BYBT中部分揮發物的合成途徑

▲ 不同季節BYBT的揮發性代謝物差異分析。（A）Venn圖；（B）不同季節BYBT的中常見差異揮發性化合物的結構和風味；（C）51種差異揮發性化合物熱圖；（D）SU-BT和SP-BT比較中差異揮發性化合物風味和含量變化桑基圖；（E）AU-BT和SP-BT比較中差異揮發性化合物風味和含量變化?；鶊D

▲ 不同季節BYBT的非揮發性代謝物分布特征。（A）紅茶茶湯的主要成分；（B）三個季節樣品中非揮發性化合物含量分類圓環圖；（C）主成分分析；（D）不同對比組的韋恩圖；（E）三個組別中存在顯著差異的非揮發性化合物熱圖

審稿：中國農業科學院茶葉研究所 李佳副研究員

來源: 中國茶葉學會

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