不同品种毛茶水浸出物成分及抗氧化、降血糖活性研究

Components, antioxidant and hypoglycemic activities of water extracts from different varieties of raw tea

关键词:  不同品种, 毛茶, 水浸出物成分, 抗氧化活性, 降血糖活性

Key words:  different varieties, raw tea, water extract components, antioxidant activity, hypoglycemic activity

摘要:

为比较7个不同品种毛茶水浸出物活性成分及体外抗氧化与降血糖活性的差异,确定各成分与活性之间的相关性,该文选取制作六堡茶常用的7个茶树品种制备的毛茶作为研究对象,测定毛茶水浸出物及其浸膏中总多酚、总黄酮、茶多糖的含量,以DPPH·清除能力、ORAC值和α-葡萄糖苷酶、α-淀粉酶抑制作用为指标评价毛茶水浸出物的抗氧化和降血糖活性,并采用Pearson进行相关性分析。结果表明:(1)7个茶树品种毛茶水浸出物、总多酚、总黄酮、茶多糖含量均存在显著差异,含量最高的分别为黄金茶(53.42%± 0.14%)、桂红4号(40.87%±1.09%)、云南大叶种(27.17%±0.26%)、福云6号(2.70%±0.02%)。(2)对DPPH·清除能力、ORAC值存在显著差异,在两种评价方法中均显示较好抗氧化效果的品种为六堡群体种、桂红4号、宛田种。(3)对α-葡萄糖苷酶、α-淀粉酶的抑制作用均显著强于阳性对照阿卡波糖,在两种评价方法中均显示较好降血糖效果的品种为六堡群体种、桂红4号、桂青种。(4)抗氧化、降血糖活性均与总多酚、总黄酮含量有较强正相关。综上认为,六堡群体种、桂红4号、宛田种、桂青种的毛茶品质均较好,其中六堡群体种、桂红4号同时具有开发成抗氧化、降血糖功能食品的前景,宛田种、桂青种分别具有开发成抗氧化、降血糖功能食品的潜力; 总多酚、总黄酮对毛茶体外抗氧化、降血糖活性的贡献较大,在毛茶进一步的加工利用过程中应着重注意对这类成分的保护。该研究结果为开发抗氧化、降血糖活性更好的六堡茶产品在毛茶原料筛选和加工方式选择方面提供了科学依据。

Abstract:

To compare the differences in the active components, the antioxidant and hypoglycemic activities in vitro between seven different varieties of raw tea water extracts, determine the correlation between each ingredient and activity. The contents of total polyphenols, total flavonoids and tea polysaccharides in the water extracts of raw tea and its infusion were determined. The antioxidant and hypoglycemic activities of raw tea water extracts were evaluated by DPPH· scavenging ability, ORAC value and α-glucosidase and α-amylase inhibition as indicators, and Pearson correlation analysis was performed. The results were as follows:(1)there were significant differences in the contents of water extract, total polyphenols, total flavonoids and tea polysaccharides among the seven varieties, while the highest contents were found in Golden tea(53.42%±0.14%), Guihong No.4(40.87%±1.09%), Yunnan big leaf species(27.17%±0.26%)and Fuyun No.6(2.70%±0.02%), respectively.(2)There were also significant differences in DPPH· scavenging ability and ORAC values among the seven varieties, while the varieties showing better antioxidant effects in both evaluation methods were the Liupao group species, Guihong No.4 and Wantian species.(3)The inhibition of α-glucosidase and α-amylase by the water extracts of seven varieties was significantly stronger than those of acarbose positive control. The varieties showing better hypoglycemic effects in both evaluation methods were Liupao group species, Guihong No.4 and Guiqing species.(4)The antioxidant and hypoglycemic activities were all strongly and positively correlated with the contents of total polyphenols and flavonoids. In summary, raw tea quality of Liupao group species, Guihong No.4, Wantian species and Guiqing species are better, among which Liupao group species and Guihong No.4 have the prospect of developing antioxidant and hypoglycemic functional food; Wantian species and Guiqing species have the potential of developing antioxidant and hypoglycemic functional food respectively. Total polyphenols and total flavonoids have a great contribution to the in vitro antioxidant and hypoglycemic activities of raw tea, so that attention should be paid to the protection of such components during the further processing and utilization of raw tea. The results of this study provide a scientific basis for the development of Liupao tea products with better antioxidant and hypoglycemic activities in the selection of raw materials and processing methods of raw tea.