摘要
为建立一种快速无损评价茶叶/茶汤化学品质和色泽的方法,本试验选取7种代表性茶叶样本为材料,利用傅里叶变换中红外光谱(FTIR)技术,以开水冲泡方式制备茶汤冻干粉,对茶叶与茶汤共14个样本进行FTIR光谱采集分析。通过聚类分析、光谱曲线拟合、定性分析,并结合常规化学法检测茶多酚、茶多糖、可溶性糖、游离氨基酸、主要儿茶素类和生物碱含量。结果表明,不同茶叶光谱明显不同,由于茶叶加工工艺造成的脂类、儿茶素类、咖啡碱、游离氨基酸及叶绿素含量差异,利用1 800~1 170 cm^-1狭窄区域的光谱特征,可实现茶叶分类。茶叶与对应茶汤的光谱也存在明显差异,体现了茶叶在冲泡过程中的物质变化。主要特征峰区(位)为:2 925/2 855 cm^-1代表脂类饱和烃链-CH2振动,1 700 cm^-1峰位对应儿茶素类和咖啡碱,1 534 cm^-1对应着叶绿素脱镁过程,1 551/1 556 cm^-1和1 500/1 497 cm^-1为叶绿素中亚甲基桥的伸缩振动,1 516/1 517 cm^-1为木质素中的苯环C=C伸缩振动。本研究为市场中茶叶、新型速溶茶粉样品化学品质检测提供了一种有效、快速的无损分析方法。
In order to establish a rapid and nondestructive method for the evaluation of chemical quality and color of tea leaf/beverage, seven representative tea samples were selected as materials, and the freeze-dried powder of tea was prepared from boiling water beverages. The fourier transform mid-infrared spectroscopy(FTIR) spectra for 14 samples, including 7 kinds of tea leaves and their beverages, were collected. The content of polyphenols, polysaccharide, soluble sugar, main catechins and alkaloid were determined through clustering analysis, spectral curve fitting and quantification analysis with the combination of common chemical analysis methods. The results showed that the spectra of different tea types were significantly different, which reflected the differences of lipids, catechins, free amino acid, caffeine and chlorophyll content caused by tea processing. The classification of tea leaves could be achieved by using the narrow characteristic region of 1 800-1 170 cm^-1. The spectrum of tea leaves and corresponding beverage also had significant difference, demonstrating the tea compounds change in the process of boiling and dissolving. The main characteristic peak area(location) were as following: 2 925/2 855 cm^-1 represented-CH2 vibration in saturated lipid, 1 700 cm^-1 for catechins and alkaloids, 1534 cm^-1 for the chlorophyll demineralization process, 1 551/1 556 cm^-1 and 1 500/1 497 cm^-1 for the stretching vibration of the middle methyl bridge of chlorophyll, and 1 516/1 517 cm^-1 for the benzodiazepine C=C stretching vibration in lignin. This study provides an effective and rapid nondestructive analysis method of chemical quality test for tea leaf and instant tea in the market.
作者
许娜
陈玲
马玉涵
刘超
董荣荣
姜浩
XU Na;CHEN Ling;MA Yuhan;LIU Chao;DONG Rongrong;JIANG Hao(School of Tea&Food Science,Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization,Hefei,Anhui 230036;College of Life and Health Sciences,Anhui Science and Technology University,Fengyang,Anhui 233100)
出处
《核农学报》
CAS
CSCD
北大核心
2020年第3期564-572,共9页
Journal of Nuclear Agricultural Sciences
基金
安徽省自然科学基金面上项目(1808085MC71)
安徽省博士后项目(2017B230)
安徽省教育厅高校自然科学重点项目(KJ2016A239、KJ2019A0820).
关键词
茶叶
茶汤
傅里叶变换中红外光谱
化学品质
tea leaf
tea beverage
fourier transform mid-infrared spectroscopy
chemical quality
