白茶散茶与茶饼在色泽、滋味及香气组分上的差异研究

为探明压饼工艺对白茶品质的影响,本文以白牡丹散茶为原料制成白牡丹茶饼,比较了压饼工艺前后白茶散茶与茶饼之间在干茶色泽、滋味及香气组分上的差异。结果表明,散茶色泽鲜绿、滋味浓、香气以嫩香为主,而茶饼色泽黄、滋味浓醇、香气以果香与甜香为主。与散茶相比,茶饼色泽的红绿度(a*)极显著(p<0.01)增加,干茶色泽变红;总叶绿素、叶绿素a和b含量均极显著(p<0.01)降低;水浸出物、茶多酚、黄酮与"茶三素"含量显著(p<0.05)降低,而氨基酸、可溶性糖含量显著(p<0.05)提高,引起酚氨比极显著(p<0.01)降低。与散茶相比,茶饼中醇类香气总量和香叶醇组分相对含量降低9%左右,而芳樟醇氧化物、烯类、酮类、酯类和杂氧化合物香气平均相对总量分别增加1.86%、1.89%、1.87%、3.42%和0.83%;香气组分主成分分析得出,茶饼香气质量综合得分比散茶高4~7分。

Study on the Differences of Color,Taste and Aroma Constituents in White Loose Tea and White Tea Pine

To figure out the effects of pressing process in white tea quality,white loose tea(WLT)was used to produce white tea pine(WTP),then the differences between WLT and WTP in raw tea color,taste and aroma constituents were analyzed in this study. Results indicated that the WLT appearance was green,soup taste was strong and main fragrance was tenderness. However,the WTP leaves showed yellow appearance,soup taste became mellow and main fragrance was fruity and sweet. Compared with WLT,the WTP dried leaves transferred from green to red caused by the significantly increasing of red and green degree(p<0.01)and significantly decreasing of total chlorophyll,chlorophyll a and chlorophyll b(p<0.05). The aqueous extract,tea polyphenol,flavonol,theaflavin,thearubigins,theabrownin contents and tea polyphenol and amino acids ratio in WTP was significantly lower than WLT(p<0.05),whereas amino acid and soluble sugar contents significantly increased(p<0.01). After pressing process,the total alcohols aroma average relative contents and geraniol decreased about 9%. However,the linalool oxides,alkenes,ketones,esters and oxides aroma relative contents increased by 1.86%,1.89%,1.87%,3.42%,0.83%,respectively after pressing. The fragrance principal component analysis indicated that the comprehensive scores of WTP were 4 ~7 scores higher than that of WLT.