食品科学 ›› 2020, Vol. 41 ›› Issue (22): 252-259.doi: 10.7506/spkx1002-6630-20191020-206

• 成分分析 • 上一篇    下一篇

不同季节凌云白毫绿茶的香气成分差异分析

田甜,韦锦坚,文金华,曾祥林   

  1. (1.广西民生中检联检测有限公司,广西 南宁 530000;2.广西南亚热带农业科学研究所,广西 龙州 532415)
  • 出版日期:2020-11-25 发布日期:2020-11-26
  • 基金资助:
    广西公益性基金项目(GXNYRKS201609)

Seasonal Variability of Aroma Components of Lingyun Pekoe Green Tea

TIAN Tian, WEI Jinjian, WEN Jinhua, ZENG Xianglin   

  1. (1. Guangxi Minsheng Sino Assessment Group, Nanning 530000, China;2. Guangxi South Subropical Agricultural Science Research Institute, Longzhou 532415, China)
  • Online:2020-11-25 Published:2020-11-26

摘要: 为了解凌云白毫绿茶的主要香气成分,同时探明不同季节凌云白毫绿茶的香气成分差异。通过动态顶空-气相色谱-质谱技术对春、夏、秋3 季凌云白毫绿茶的香气成分进行定性定量测定,基于茶样中各香气成分的相对含量,通过偏最小二乘-判别分析(partial least square-discriminant analysis,PLS-DA)建立不同季节茶叶判别模型,然后找到对分类起关键作用的香气成分,最后通过绘制热图和层次聚类分析确定各关键香气成分在不同季节凌云白毫绿茶中的分布规律。结果表明,本研究共鉴定出37 种化合物,其中醇类和醛类化合物数量较多;凌云白毫绿茶主要香气成分为芳樟醇、正戊醇、香叶醇、L-薄荷醇、异丁醛、异戊醛、壬醛、乙酸乙酯、二甲硫醚、吲哚。建立的PLS-DA模型可以将3 个季节的茶样明显区分,且模型可靠;本研究最终鉴定出12 种香气成分区分不同季节凌云白毫绿茶的关键化合物,分别为壬醛、β-紫罗兰酮、L-薄荷醇、3,5-辛二烯-2-酮、反-橙花叔醇、苯甲醇、正戊醇、十三烷、顺式-2-戊烯-1-醇、顺-茉莉酮、十四烷、叶醇。结合热图及12 种香气成分的聚类分析,表明L-薄荷醇和β-紫罗兰酮在秋茶中相对含量最高,是凌云白毫秋茶区别于春茶和夏茶的特征香气成分,主要表现为花香、果香、薄荷味;苯甲醇和正戊醇在春茶中相对含量较高,是凌云白毫春茶区别于夏茶和秋茶的特征香气成分,主要表现为果香、杏仁苦味;壬醛、3,5-辛二烯-2-酮、反-橙花叔醇在夏茶中相对含量最高,是夏茶的特征香气成分,香气主要为柑橘柠檬香、水果甜香。

关键词: 季节;凌云白毫绿茶;香气成分;动态顶空-气相色谱-质谱;偏最小二乘-判别分析

Abstract: This study aimed to understands the main aroma components of Lingyun pekoe green tea and to explore the differences in aroma components among different harvest seasons. Dynamic headspace-gas chromatography-mass spectrometry (DHS-SPME-GC-MS) was used to determine the aroma components of Lingyun pekoe tea in spring, summer and autumn. Based on the relative content of each aroma component, we used partial least square-discriminant analysis (PLS-DA) to establish discriminant models for tea samples harvested in different seasons, then found out the aroma components crucial to tea sample classification, and finally drew a heat map to determine the distribution pattern of the key aroma components in different harvest seasons using hierarchical cluster analysis (HCA). Results showed that a total of 37 compounds were identified in the tea samples, the predominant ones being alcohols and aldehydes. The main aroma components were linalool, n-amyl alcohol, geraniol, L-menthol, isobutyraldehyde, isoglutaraldehyde, nonaldehyde, ethyl acetate, dimethyl sulfide and indoles. The established PLS-DA model could obviously distinguish tea samples harvested in the three seasons, with good reliability. A total of 12 aroma components, nonaldehyde, betarecolone, l-menthol, 3,5-octadiene-2-ketone, trans-orange-flower tert alcohol, benzyl alcohol, n-amyl alcohol, tridecane, cis-2-pentene-1-alcohol, cis-jasmonone, tetradecane and leaf alcohol were identified as the key compounds to distinguish Lingyun pekoe tea in different seasons. Collectively, the heat map and cluster analysis of the 12 aroma components showed that l-menthol and beta-violetone were the most abundant in autumn tea as its characteristic aroma components, which were different from those of spring tea and summer tea and were mainly associated with floral, fruity and peppermint-like aromas. Benzyl alcohol and n-amyl alcohol were the most abundant in spring tea as its characteristic aroma components, which distinguished spring tea from summer tea and autumn tea and mainly contributed to fruity aromas and apricot kernel-like bitter taste. Nonaldehyde, 3,5-octadiene-2-ketone and trans-orange flower tertiary alcohol were the most abundant in summer tea as its characteristic aroma components and were mainly responsible for lemon-like and sweet fruity aroma.

Key words: harvest seasons; Lingyun pekoe green tea; aroma components; dynamic headspace-gas chromatography-mass spectrometry; partial least square-discriminant analysis

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