Quality and stable isotope characteristics and identification of Wuyi organic tea

doi:10.16178/j.issn.0528-9017.20230629

Abstract

Abstract:

Wuyi County is the first “Hometown of Organic Tea” in China. In order to explore the key characteristic indicators of Wuyi organic tea, this study collected tea samples from different fertilizers and organic cultivation years in Wuyi County in early and late spring. Chemical analysis, sensory evaluation, and elemental analysis stable isotope ratio mass spectrometry were used to analyze the main chemical components, sensory quality, the content of carbon, nitrogen elements, and isotope(δ¹³C、δ¹⁵N) content of tea. The results showed that compared with the tea treated with chemical fertilizers, tea treated with organic fertilizers had a higher content of free amino acids, better aroma and taste. The content of δ¹⁵N was higher. Most of the chemical composition and stable isotope ratios were higher in tea samples grown organically for 5-10 years. Establishing a partial least squares discriminant model using chemical composition and carbon and nitrogen element composition can effectively distinguish between organic and conventional tea cultivation. Combining variable importance for projection analysis, it indicated that the content of δ¹⁵N and tea polyphenol were key characteristic indicators for distinguishing organic tea. This article provides technical support and scientific basis for promoting the healthy development of the organic tea industry and market regulation.

Key words: organic tea, quality components, stable isotope, partial least squares method

CLC Number:

S571.1

XU Huan, GUO Zuchuang, LIU Ruimin, SHAO Shengzhi, YUAN Yuwei, LI Chunlin. Quality and stable isotope characteristics and identification of Wuyi organic tea[J]. Journal of Zhejiang Agricultural Sciences, 2024, 65(7): 1687-1694.

Figures/Tables 10

References 22

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栽培方式	肥料种类	早春	晚春	小计
常规栽培	化肥	3	3	6
有机栽培	菜籽饼	3	3	18
	商品有机肥(0~5 a)	3	3
	商品有机肥(>5~10 a)	0	3
	商品有机肥(>10 a)	0	3
合计		9	15	24

栽培方式	肥料种类	早春	晚春	小计
常规栽培	化肥	3	3	6
有机栽培	菜籽饼	3	3	18
	商品有机肥(0~5 a)	3	3
	商品有机肥(>5~10 a)	0	3
	商品有机肥(>10 a)	0	3
合计		9	15	24

肥料种类	早春			晚春
肥料种类	水浸出物含量	茶多酚含量	游离氨基酸含量	水浸出物含量	茶多酚含量	游离氨基酸含量
化肥	50.7±0.2	20.3±0.1	4.8±0.0	45.6±0.3	15.2±0.0	2.4±0.2
菜籽饼	50.1±0.3	16.3±0.1	5.2±0.2	48.5±1.3	17.2±0.9	3.1±0.3
商品有机肥	49.5±0.3	18.0±0.1	6.1±0.2	47.2±0.3	15.5±0.5	3.2±0.3

肥料种类	早春			晚春
肥料种类	水浸出物含量	茶多酚含量	游离氨基酸含量	水浸出物含量	茶多酚含量	游离氨基酸含量
化肥	50.7±0.2	20.3±0.1	4.8±0.0	45.6±0.3	15.2±0.0	2.4±0.2
菜籽饼	50.1±0.3	16.3±0.1	5.2±0.2	48.5±1.3	17.2±0.9	3.1±0.3
商品有机肥	49.5±0.3	18.0±0.1	6.1±0.2	47.2±0.3	15.5±0.5	3.2±0.3

肥料种类	外形	汤色	香气	滋味	叶底
化肥	条索紧结,略曲,有毫,略有锋苗,稍带朴,深绿稍偏黄尚润	较嫩绿明亮	较高,略有嫩香	尚醇,微涩(欠鲜爽)	较嫩软,有芽,有嫩茎、摊张,较绿亮
菜籽饼	条索紧实,略曲,带茎梗、朴片,深绿稍偏黄尚润	尚绿亮	较高爽,尚鲜,有嫩香,略有花香	较醇,尚厚,较清鲜	尚嫩,多嫩茎、摊张,尚绿亮
商品有机肥	条索紧结,较壮,显毫,有锋苗,深绿稍偏黄尚润	尚嫩绿(偏黄)明亮	较高,有嫩香,略有花香,略熟闷	醇厚,尚鲜,微熟甜	较细嫩,多芽,较嫩绿亮