HS-SPME-GC-MS Analysis of Volatile Components of Congou Black Tea Processed from Baojing Huangjincha 1 from Different Harvesting Seasons
HUANG Hao, YU Penghui, ZHAO Xi, ZHONG Ni, ZHENG Hongfa
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In order to evaluate the aroma characteristics of Congou black tea from different harvesting seasons, Congou black tea were processed from one bud with one leaf from the cultivar Baojing Huangjincha 1 harvested in spring, summer and autumn and were analyzed for their volatile components by using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Meanwhile, sensory evaluation was conducted to investigate the effects of different harvesting seasons on the volatile aroma characteristics of Congou black tea. The results showed that the aroma of Congou black tea was mainly characterized as sweet and fragrant for all three seasons, specifically pure sweet aroma for spring tea, strong sweet aroma for summer tea, and sweet and flowery aroma for autumn tea. In addition, the flavor index (FI) of autumn tea was the highest and its aroma quality was the best, followed by summer and spring teas. This was consistent with the results of sensory evaluation. A total of 80 aroma components were detected and identified in the three samples, and 51, 63 and 66 in spring, summer and autumn teas respectively. In total, 40 aroma components were common to these samples mainly including alcohols, aldehydes, hydrocarbons, esters and ketones. The contents of aroma components in Congou black tea were analyzed by principal component analysis (R2X = 0.941, Q2 = 0.825), and we further established a partial least squares-discriminant analysis model (R2X = 0.972, R2Y = 0.994, and Q2 = 0.982) to effectively distinguish the three tea samples. There were 13 landmark compounds that differed among these samples, including methyl salicylate, benzaldehyde, myrcene, 3,7-octad iene-2,6-diol,2,6-dimethyl, 1-ethyl-1H-pyrrole-2-carbaldehyde, safranal, (E)-nerolidol, styrene, 2-octen-1-al, trans-2-decenal, phenylethyl alcohol, 2-[(2S,5S)-5-ethenyl-5-methyltetrahydrofuran-2-yl]propan-2-ol-2H-pyran, and (E)-2-nonenal.