Insight into the taste profiles of green tea made with fresh tea leaves plucked in summer

Abstract

Purpose This study aims to investigate the suitability of summer-plucked fresh tea leaves (FTL-GT) for green tea production, challenging the common experience-based claim of their unsuitability. It seeks scientific evidence to support or refute this claim. Design/methodology/approach The study comprehensively analyzes the taste properties of green tea (GT) made from FTL-GT, including non-volatiles like polyphenols, caffeine, free amino acids, total sugar and L-theanine. Various indices during processing, such as dose-over-threshold (Dot) factors, catechin quality index (CQI), phenol/amino ratio (PAR) and non-esterified/esterified catechins ratio (NER). Additionally, sensory evaluation is conducted. Findings FTL-GT exhibits high CQI (256.38) and NER (0.58) and low PAR (5.37), indicating its suitability for producing high-quality GT. Green tea made from FTL-GT contains high catechin content and exhibits strong, mellow and umami-like tastes. EGCG, caffeine and L-theanine with high Dot factors of 680.47, 250.89 and 16.69, respectively, are identified as key contributors to the astringent, bitter and umami-like tastes in GT. Cysteine, with a Dot factor of 6.55, is the primary compound responsible for the sweet taste. Research limitations/implications This study primarily focuses on the taste properties of green tea made from summer-plucked fresh tea leaves but does not explore potential variations in other quality attributes such as aroma or appearance. Additionally, the study was conducted using a specific set of tea leaves and processing methods, limiting the generalizability of the findings. Implications for the tea industry include the potential to expand production seasons and improve the quality of green tea by utilizing summer-plucked leaves. Practical implications The study suggests that tea producers can consider using summer-plucked fresh tea leaves for green tea production, potentially expanding their production seasons and increasing yield. This could lead to more sustainable tea farming practices and higher quality green tea products. Additionally, the identified taste-active compounds and indices can guide tea processors in optimizing production methods to enhance the taste profiles of green tea. Social implications By demonstrating the suitability of summer-plucked fresh tea leaves for green tea production, this study could contribute to the economic development of tea-growing regions by providing farmers with an additional source of income. Furthermore, the promotion of high-quality green tea made from these leaves could enhance cultural appreciation and consumption of tea, fostering a deeper connection to traditional tea practices and encouraging healthy lifestyles among consumers. Originality/value The originality of this study lies in its comprehensive analysis of the taste properties of green tea made with summer-plucked fresh tea leaves, which challenges the commonly held belief based on experience that these leaves are not suitable for green tea production. The study provides scientific evidence to support the suitability of FTL-GT for green tea production and reveals the taste profiles of summer green tea. This information serves as a valuable reference for the tea industry and researchers interested in optimizing green tea production and quality.