不同品种乌龙茶烘焙前后化学成分差异及体外活性

Chemical Composition Difference and in Vitro Activity of Different Varieties of Oolong Tea before and After Roasting

摘要:

为研究不同乌龙茶原料经烘焙处理后物质基础变化规律及活性差异，分析了不同乌龙茶原料烘焙前后中的总多酚、总黄酮茶多糖、儿茶素组分及咖啡碱含量差异，采用体外酶生化反应手段，考察不同乌龙茶原料及成品对α-葡萄糖苷酶、脂肪酶和黄嘌呤氧化酶的抑制能力。结果显示，茶多酚含量（质量分数）由原料中的13.75%~15.59%下降至成品的12.41%~14.14%，铁观音、肉桂高于老枞水仙、三印水仙和大红袍（P<0.05）；原料中总黄酮含量（质量分数）在0.71%~1.00%之间，铁观音原料总黄酮含量最低，与其他原料相比有显著差异（P<0.05），除铁观音外，其余乌龙茶样品总黄酮含量在烘焙处理前后差异不显著（P>0.05）；原料中茶多糖含量（质量分数）为1.14%~1.82%，烘焙后上升到成品的1.64%~2.12%。所有样品均表现出对于α-葡萄糖苷酶、脂肪酶和黄嘌呤氧化酶的抑制能力，且烘焙后的成品对于α-葡萄糖苷酶、脂肪酶的抑制能力减弱，肉桂表现出较高的抑制α-葡萄糖苷酶及脂肪酶活性的能力。乌龙茶烘焙后对于黄嘌呤氧化酶的抑制能力增强，IC50 值由13.21~17.42 mg/mL降低为成品的10.26~14.38 mg/mL。

Abstract:

In order to study the changing trend of mass base and difference in activity of different raw oolong tea materials after roasting, the differences in the contents of total polyphenols, total flavonoids, tea polysaccharides, catechins and caffeine of different raw oolong tea materials before and after roasting were analyzed. In vitro enzymatic biochemical reaction was used to investigate the inhibitory abilities of different oolong tea raw materials and finished products against α-glucosidase, lipase and xanthine oxidase. The results showed that the content of tea polyphenols decreased from 13.75%~15.59% in raw materials to 12.41%~14.14% in the finished products, with the contents of Tieguanyin and Rougui being slightly higher than those of Old Fir Narcissus, Sanyin Narcissus and Dahongpao (P<0.05). The content (mass fraction) of total flavonoids in the raw materials ranged from 0.71% to 1.00%, and the content of total flavonoids in Tieguanyin raw materials was the lowest, which was significantly different from those of other raw materials (P<0.05). Except for Tieguanyin, the contents of total flavonoids in other oolong tea samples were insignificantly different before and after roasting (P>0.05). The contents of tea polysaccharides in the raw materials were 1.14%~1.82%, which increased to 1.64%~2.12% in the finished products after baking. All the samples showed the inhibitory abilities against α-glucosidase, lipase and xanthine oxidase, and the finished products after baking exhibited weaker inhibitory abilities against α-glucosidase and lipase. Rougui showed higher abilities to inhibit α-glucosidase and lipase activities. After roasting, oolong tea had an enhanced ability to inhibit xanthine oxidase, with the IC50 values decreasing from 13.21~17.42 mg/mL to 10.26 mg/mL~14.38 mg/mL for the finished product