Effect of variable temperature spreading processing on the flavor and quality of Longjing tea

doi:10.16178/j.issn.0528-9017.20240709

Abstract

Abstract:

Spreading is the first key process in the processing of Longjing tea, and is the cornerstone of the good flavor quality formation of Longjing tea. In this study, Longjing tea was processed using four different spreading methods: “traditional room temperature” spreading (CK), “room temperature+refrigeration+room temperature” variable temperature spreading(V1), “room temperature+refrigeration+freezing+room temperature” variable temperature spreading (V2), and “room temperature+freezing+room temperature” variable temperature spreading (V3). Through comparative analysis of sensory quality and flavor chemical contents, as well as the correlation between sensory evaluation scores and flavor chemical contents, the effect of variable temperature spreading treatment on the flavor quality of Longjing tea was explored. The results showed that the sensory evaluation scores of Longjing tea processed by V1, V2, and V3 were higher than those of CK. The V1, V2, and V3 had better qualities than CK in terms of flatness and uniformity in appearance, brightness in soup, aroma persistence, and mellow taste. Moreover, the sensory quality of Longjing tea processed by V3 was relatively the best. The contents of tea polyphenols, water extracts, catechins in V1, V2, and V3 was significantly (p<0.05) higher than that in CK, while those in V3 was significantly higher than those in V1 and V2, which was consistent with the trend of changes in sensory evaluation scores. The contents of free amino acids in V2 and V3 was significantly higher than that in CK and V1. The caffeine content of V1, V2, and V3 was significantly higher than that of CK, while there was no significant difference in caffeine content among V1, V2, and V3. Compared with CK, V1, V2, and V3 had higher contents of EGCG, EGC, and GCG, while V1, V2, and V3 had lower contents of ECG, CG. Compared with CK and V1, V2 and V3 had higher contents of EC, C, and GC. The GC,EGCG,C,EC,free amino acids, tea polyphenols, and water extracts were the main flavor quality contributing substances of Longjing tea. Freezing had a greater effect on the flavor quality of Longjing tea after spreading than refrigeration. The variable temperature spreading process has significantly improved the flavor and quality of Longjing tea, providing technical support and theoretical basis for the formation and regulation of Longjing tea quality research.

Key words: Longjing tea, spreading, processing technology, flavor, quality, chemical composition

CLC Number:

S571.1

CUI Hongchun, YU Jizhong, SHI Daliang, ZHANG Jianyong, WANG Feng, ZHANG Zaiqing. Effect of variable temperature spreading processing on the flavor and quality of Longjing tea[J]. Journal of Zhejiang Agricultural Sciences, 2026, 67(1): 148-155.

Figures/Tables 5

References 19

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摊青处理	外形25%		汤色10%		香气25%		滋味30%		叶底10%		总分
摊青处理	评语	评分	评语	评分	评语	评分	评语	评分	评语	评分	总分
CK	较扁平,较光滑,绿	88.0	黄绿,亮	88.5	清香,稍有青草气	86.0	较浓醇	88.0	黄绿较亮, 成朵	91.0	87.85
V1	扁平,较光滑, 黄绿	89.0	嫩绿明亮, 清澈	93.0	清香,持久	91.0	浓,较醇爽	90.5	嫩,绿亮成朵,较匀	92.0	90.65
V2	扁平,较光滑, 黄绿,尚尖削	90.0	嫩绿明亮, 清澈	94.0	栗香,浓郁, 尚持久	92.0	浓,醇爽	92.0	嫩,绿亮成朵,较匀	93.0	91.80
V3	扁平,较光滑, 黄绿,尚尖削	90.0	嫩绿明亮, 清澈	94.0	栗香,浓郁, 较持久	93.0	浓,醇爽	93.0	嫩,绿亮成朵,较匀	93.0	92.35

摊青处理	外形25%		汤色10%		香气25%		滋味30%		叶底10%		总分
摊青处理	评语	评分	评语	评分	评语	评分	评语	评分	评语	评分	总分
CK	较扁平,较光滑,绿	88.0	黄绿,亮	88.5	清香,稍有青草气	86.0	较浓醇	88.0	黄绿较亮, 成朵	91.0	87.85
V1	扁平,较光滑, 黄绿	89.0	嫩绿明亮, 清澈	93.0	清香,持久	91.0	浓,较醇爽	90.5	嫩,绿亮成朵,较匀	92.0	90.65
V2	扁平,较光滑, 黄绿,尚尖削	90.0	嫩绿明亮, 清澈	94.0	栗香,浓郁, 尚持久	92.0	浓,醇爽	92.0	嫩,绿亮成朵,较匀	93.0	91.80
V3	扁平,较光滑, 黄绿,尚尖削	90.0	嫩绿明亮, 清澈	94.0	栗香,浓郁, 较持久	93.0	浓,醇爽	93.0	嫩,绿亮成朵,较匀	93.0	92.35