桑叶乌龙茶制作工艺流程中生物活性物质的稳定性研究

Study on the Stability of Bioactive Substances in the Making Process of Mulberry Leaf Oolong Tea

桑叶乌龙茶因含有桑多糖、桑多酚、游离氨基酸等多种有效成分,而具有调节肠道菌群、诱导脂肪细胞凋亡、抑制前脂肪细胞分化和肝脏脂肪再生等生物学功能。本研究对四种桑叶乌龙茶(轻杀青、轻烘干;轻杀青、重烘干;重杀青、轻烘干;重杀青、重烘干)在加工工艺流程中茶多酚、可溶性总糖、游离氨基酸的含量变化及活性物质稳定性进行分析。根据国家标准检测方法GB/T 8313—2018测定重杀青和轻杀青的茶多酚含量分别为0.52%、0.86%,重烘干和轻烘干的茶多酚含量分别为0.81%、0.74%,差异均不显著(P>0.05)。根据国家标准检测方法GB/T 8314—2013测定游离氨基酸含量,重杀青和轻杀青的游离氨基酸含量分别为0.16%、0.19%,差异未达到极显著水平(0.01<P<0.05);重烘干和轻烘干的游离氨基酸含量分别为0.17%、0.18%,差异不显著(P>0.05)。采用蒽酮比色法测定可溶性总糖含量,重杀青和轻杀青的可溶性总糖含量分别为26.40%、19.65%,差异未达到极显著水平(0.01<P<0.05);重烘干和轻烘干的可溶性总糖含量分别为24.74%、23.74%,差异不显著(P>0.05)。综合分析测定结果,发现不同的桑叶乌龙茶制作工艺,各活性成分总体相对稳定,为桑叶茶制作工艺提供了参考依据。

Mulberry leaf oolong tea has biological functions such as regulating intestinal flora,inducing apoptosis of adipocytes,inhibiting preadipocyte differentiation and liver fat regeneration because it contains many effective components such as mulberry polysaccharide,mulberry polyphenols,free amino acids,etc.In this study,the content changes of tea polyphenols,soluble total sugars,free amino acids and the stability of active substances of four mulberry leaf oolong teas(light fixation,light drying;light fixation,heavy drying;heavy fixation,light drying;heavy fixation,heavy drying)in the making process were analyzed.According to the national standard test method GB/T 8313-2018,the content of tea polyphenols in heavy and light fixation tea was 0.52%and 0.86%,respectively,and the content of tea polyphenols in heavy and light drying tea was 0.81%and 0.74%,respectively,with no significant difference(P>0.05).The content of free amino acids was determined according to the national standard test method GB/T 8314-2013.The content of free amino acids in heavy and light fixation tea was 0.16%and 0.19%,respectively,and the difference did not reach an extremely significant level(0.01<P<0.05);The content of free amino acids in heavy drying and light drying tea was 0.17%and 0.18%,respectively,with no significant difference(P>0.05).The content of total soluble sugar was determined by anthrone colorimetric method.The content of total soluble sugar in heavy and light fixation was 26.40%and 19.65%,respectively,and the difference did not reach an extremely significant level(0.01<P<0.05);The total soluble sugar content of heavy drying and light drying was 24.74%and 23.74%,respectively,with no significant difference(P>0.05).The comprehensive analysis of the determination results showed that the active components were relatively stable in general in different mulberry leaf oolong tea production processes,which provided a reference for mulberry leaf tea production processes.