Variations in Fatty Acids Affected Their Derivative Volatiles during Tieguanyin Tea Processing

Abstract

Fatty acids (FAs) are important precursors of oolong tea volatile substances, and their famous derivatives have been shown to be the key aroma components. However, the relationship between fatty acids and their derivatives during oolong tea production remains unclear. In this study, fresh Tieguanyin leaves were manufactured into oolong tea and green tea (control), and fatty acids and fatty acid-derived volatiles (FADV) were extracted from processed samples by the sulfuric acid–methanol method and solvent-assisted flavor evaporation (SAFE), respectively. The results showed that unsaturated fatty acids were more abundant than saturated fatty acids in fresh leaves and decreased significantly during tea making. Relative to that in green tea, fatty acids showed larger variations in oolong tea, especially at the green-making stage. Unlike fatty acids, the FADV content first increased and then decreased. During oolong tea manufacture, FADV contents were significantly and negatively correlated with total fatty acids; during the green-making stage, methyl jasmonate (MeJA) content was significantly and negatively correlated with abundant fatty acids except steric acid. Our data suggest that the aroma quality of oolong tea can be improved by manipulating fatty acid transformation.

Metabolomic Profiling in Combination with Data Association Analysis Provide Insights about Potential Metabolic Regulation Networks among Non-Volatile and Volatile Metabolites in Camellia sinensis cv Baijiguan

“…In contrast, cis -3-hexenyl hexanoate was positively correlated with cis -jasmone (R = 0.85) ( Figure 6 b). Considering that hexadecenoic acid (16:1) is present in fresh tea leaves at an appreciable amount (~59 μg g −1 fresh weight) [ 83 ], these negative correlations raise an open question regarding whether hexadecenoic acid could be oxidized into hexanol, hexanate, or cis -jasmone in tea plants.…”

“…The MVA volatile synthesis pathway and fatty acid-derivative pathway are the two minor pathways contributing to the total fresh tea leaf volatile contents ( Table 1 ). However, they also make significant contributions to tea’s aroma characteristics [ 83 ]. The positive correlations between the MVA volatile synthesis pathway and the fatty acid-derivative pathway ( Figure 2 a) provide opportunities to simultaneously increase their contents and breed new tea germplasms with higher aroma quality.…”

The Dynamic Change in Fatty Acids during the Postharvest Process of Oolong Tea Production

“…According to the discrete degree of F_v_T3 and F_v_CK3 in the load diagram, we could infer that the participation of the mechanical force is an important factor in promoting the change in the principal components of FAs [30]. The FAs screened under the condition that vip >1.0 reflected that the change in fatty acid carbon chain is more obvious than the change in saturated bond [31,32]. The activity of LOX in turnover tea leaves was significantly higher than that in spreading leaves, suggesting that the LOX were significantly enhanced by the mechanical wounding.…”

Identification of Key Components Responsible for the Aromatic Quality of Jinmudan Black Tea by Means of Molecular Sensory Science

“…Different to traditional black tea, the processing methods of innovative black tea ad ditionally include turning over after the withering period (Figure 1), a method initially originating from the processes used for oolong tea. It was found that during the turning over period, the aromatic volatile compounds formatted and accumulated, finally contrib uting to the floral and fruity aroma of the processed tea [17,18]. Moreover, innovative black tea tends to be processed with aroma-enriched tea cultivars, such as Camellia sinesi cv.…”