发芽黑麦茶制备过程中营养素及茶风味变化

Changes of nutrients and tea flavor during the preparation of germinated rye tea

目的研究发芽黑麦茶制备的工艺条件和加工过程对其营养素及茶风味的影响。方法以黑麦为原料,经发芽、烘烤后制备成发芽黑麦茶,分析发芽过程中黑麦的营养物质变化,即黄酮、蛋白质、可溶性糖与植酸含量的变化,探究烘烤后发芽黑麦茶茶汤中的营养成分,即茶水浸出物、游离氨基酸、水溶性蛋白质及总酚含量的变化。并采用顶空固相微萃取-气相色谱-质谱法(head space-solid phase micro-extraction gas chromatography-mass spectrometry,HS-SPME-GC-MS)、电子鼻和电子舌等感官技术对发芽黑麦茶的挥发性物质和茶风味进行检测。结果发芽过程中黑麦蛋白含量减少,可溶性糖及黄酮含量上升。在烘焙阶段,以水溶性蛋白质和游离氨基酸含量作为茶汤营养物质的主要参照指标,确定发芽黑麦茶的最佳工艺条件为:黑麦浸泡8 h,发芽3 d,140℃烘烤40 min。电子鼻和电子舌显示出一定的辨别不同发芽时间黑麦茶的能力。GC-MS结果表明:发芽黑麦茶中的挥发性物质主要为醛类、杂环化合物和一些醇类。结论发芽和烘烤过程会显著改变黑麦中营养素和挥发性化合物的组成和含量,研究结果可为发芽黑麦茶中风味物质的形成机制和黑麦的进一步加工提供参考数据。

Objective To study the effect of germinated rye tea processing technology and preparation on the nutrients and tea flavor.Methods Germinated rye tea was prepared from rye as raw material after sprouting and baking.The changes of flavone,protein,soluble sugar content and antinutritive phytic acid content during germination were analyzed.The content of tea extract,free amino acid,water-soluble protein and total phenol of sprouted rye tea after baking were also analyzed.The volatile components and flavor of germinated rye tea were determined by head space-solid phase micro-extraction gas chromatography-mass spectrometry(HS-SPME-GC-MS),electronic nose and electronic tongue.Results During germination,rye protein content decreased,while soluble sugar and flavonoids content increased.In the baking stage,the content of water-soluble protein and free amino acids were taken as the main reference indexes of tea soup nutrients,and the optimum technological conditions were determined as follows:Rye soaked for 8 h,germinated for 3 d,and baked at 140℃for 40 min.Electronic nose and electronic tongue showed a certain ability to distinguish rye tea with different germination time.The results of GC-MS showed that the volatile substances in germinated rye tea were mainly aldehydes,heterocyclic compounds and some alcohols.Conclusion The germination and baking process will significantly change the composition and content of nutrients and volatile compounds in rye.The research results can provide reference data for the formation mechanism of flavor substances in germinated rye tea and the further processing of rye.