Dynamic Variation of Amino Acid Contents and Identification of Sterols in Xinyang Mao Jian Green Tea

Abstract

As important biomolecules in Camellia sinensis L., amino acids (AAs) are considered to contribute to the overall green tea sensory quality and undergo dynamic changes during growth. However, limited by analytical capacity, detailed AAs composition in different growth stages remains unclear. To address this question, we analyzed the dynamic changes of 23 AAs during leaf growth in Xinyang Mao Jian (XYMJ) green tea. Using amino acid analyzer, we demonstrated that most AAs are abundant on Pure Brightness Day and Grain Rain Day. After Grain Rain, 23 AAs decreased significantly. Further analysis shows that theanine has a high level on the day before Spring Equinox and Grain Rain, accounting for 44–61% of the total free AAs content in tea leaves. Glu, Pro, and Asp are the second most abundant AAs. Additionally, spinasterol and 22,23-dihydrospinasterol are first purified and identified in ethanol extract of XYMJ by silica gel column chromatography method. This study reveals the relationship between plucking days and the dynamic changes of AAs during the growth stage and proves the rationality of the traditional plucking days of XYMJ green tea.

Evaluation of Chongqing Tuo Tea at Different Grades: An Integrated Approach by Artificial and Intelligent Sensory, Non-Volatile, and Volatile Compounds Analysis

“…The heatmap and clustering analysis demonstrated that the 22 compounds could be grouped into three categories ( Figure 4 e). Six of these compounds were identified as key differential non-volatile compounds in SG, such as the umami amino acids (Thea and Asn), as well as the bitter-tasting (Glu, EC, EGC, and C) compounds [ 41 , 42 ]. A total of 7 non-volatile compounds, including EGCG, Trp, Pro, Arg, GABA, Phe, and Leu, were identified as key differential non-volatile compounds in 1G.…”

“…A total of 7 non-volatile compounds, including EGCG, Trp, Pro, Arg, GABA, Phe, and Leu, were identified as key differential non-volatile compounds in 1G. These compounds were primarily composed of sweet and umami-tasting free amino acids [ 42 ]. Nine non-volatile compounds, including GA, GC, CG, Que, Kac, Que-rut, Ile, Ser, and Val, were identified as key differential non-volatile compounds in 2G.…”

Qualitative and quantitative studies on chemical constituents of Ling‐gui‐zhu‐gan decoction: In vitro and in vivo

“…As shown in its fragmentation pathway (Supporting Information Figure S1‐3), a series of characteristic fragment ions at m/z 465.33783 Da [M‐H‐CO 2 ‐H 2 O] − and 405.31676 Da [M‐H‐CH 3 COOH] − were produced by losing CO 2, H 2 O, and CH 3 COOH from ion at m/z 527.37464 Da, respectively. By combination with the related literature and the secondary fragment ion information of the reference standard, compound 75 was identified as pachymic acid in this study [21, 22].…”

Free amino acids identification and process optimization in greengage wine fermentation and flavor formation

“…The compositions and abundance of FAAs are of much importance to the formation of food aroma and taste, which are the precursors of many volatile compounds (Hu et al., 2021; Pereira et al., 2021). According to their taste characteristics, FAAs can be divided into sweet (Gly, Ser, Ala, Pro, Thr, Cys, and Met), bitter (Arg, His, Ile, Leu, Phe, Lys, Tyr, and Val), and umami (Asp, Glu) ones (Huang et al., 2020; Sun et al., 2022). Aliphatic and aromatic alcohols, also known as higher alcohols or fusel alcohols, are predominantly formed by yeast from α‐keto acids, involving degradation of amino acids (AAs) via the Ehrlich pathway, contributing to the alcoholic flavor (Cordente et al., 2012).…”