不同窨制工艺对桂花绿茶品质的影响

Scenting Processes for Quality Improvement of Osmanthus Green Tea

【目的】探究不同窨制工艺对桂花绿茶品质的影响。【方法】对茶坯、连窨工艺桂花绿茶和传统工艺桂花绿茶进行感官审评与生化成分测定,以及采用自动热脱附-气相色谱-质谱联用仪(automatic thermal desorptiongas chromatography-mass spectrometry,ATD-GC-MS)对其进行香气分析。【结果】感官审评结果表明,连窨工艺桂花绿茶感官品质显著优于传统工艺桂花绿茶。生化成分分析结果表明,连窨工艺桂花绿茶的水浸出物、茶多酚、游离氨基酸和咖啡碱含量分别为:48.60%、19.30%、4.47%和3.10%;传统工艺桂花绿茶分别为:48.47%、19.80%、4.50%和3.17%。ATD-GC-MS结果显示,3类茶样中共鉴定出40种香气成分,包括醇类、酮类、酯类、醛类、烯类以及其他类香气成分;与茶坯相比,香型为薰衣草香、玫瑰香的1-辛烯-3-醇相对含量显著降低,玫瑰和橙花香的橙花醇,紫罗兰香、花香的β-紫罗酮,甜紫罗兰香气的5,6-环氧-β-紫罗酮在连窨工艺桂花绿茶中相对含量显著增加;香型为花香、新鲜果香、熟苹果香气的异戊酸叶醇酯、橙花醇和β-紫罗酮在传统工艺桂花绿茶中显著高于茶坯;与传统窨制工艺相比,连窨工艺的橙花醇和β-紫罗酮相对含量均显著增加。【结论】不同窨制工艺对桂花绿茶生化成分、香气物质影响较大,利用“一连窨”+“一窨一提”的连窨工艺制作的桂花绿茶其香气和滋味优于传统工艺,其中橙花醇、β-紫罗酮是连窨工艺桂花绿茶的特征性香气成分。

【Objective】Effects of scenting process on quality of osmanthus green tea(OGT)were analyzed.【Method】Sensory evaluation,biochemical determination,and automatic thermal desorption-gas chromatography-mass spectrometry(ATD-GC-MS)were conducted on raw tea leaves,scented OGTs,and a traditional OGT.The scented OGTs made by using various scenting processes were all judged by the sensory panel to be significantly superior to the traditionally OGT in quality.【Result】The contents of water extracts,tea polyphenols,free amino acids,and caffeine were 48.60%,19.30%,4.47%,and 3.10%,respectively,in the scented OGTs,while 48.47%,19.80%,4.50%,and 3.17%,respectively,in the traditional product.Forty aromatics including alcohols,ketones,esters,aldehydes,alkenes,and other volatiles were isolated from the various samples.The contents of isovalerate,nerol,andβ-ionone of the floral,fresh fruit,and ripe apple aroma type were significantly higher in the traditional OGT than in the tea leaves.On the other hand,the scented OGTs had significantly lower relative content of 1-octen-3-ol that is characterized as lavender and rose fragrance than did the leaves from which they were made.But nerol andβ-ionone were significantly higher in the scented than the traditional OGT.The scenting processes also significantly accentuated the relative contents of the rose and orange flower aroma-related nerolidol,the violet and floral fragrance-relatedβ-ionone,and the sweet violet fragrance-related 5,6-epoxy-β-ionone in OGTs.The significantly affected biochemistry,specifically aromatic compounds,elevated the sensory quality of OGT.【Conclusion】In particular,the“one-scenting+one-scenting and one-extraction”process was deemed superior for the tea making.Among the aromatics isolated,nerol andβ-ionone were believed to be the major components that characterized the scented OGTs.