ABSTRACT

The aim of current research was to determine the effect of different extraction techniques on the antioxidant capacity of green tea, black tea and ginger polyphenols. Initially, the raw materials were subjected to compositional analysis. Afterward, the bioactive moieties from all the samples were extracted through ultrasound and conventional solvent extraction method using different solvents (i.e. ethanol, methanol and water). Furthermore, the functional ingredients, namely, catechins and theaflavins were isolated by solvent partition method from green and black tea, respectively. In addition, the extracts and isolates were analyzed for their total phenolic and antioxidant profile using various spectrophotometric assays. For the quantification of theaflavins and catechins, a reverse phase HPLC system was used. Results showed that ultrasound (P > .005) proved more effectual for the extraction and isolation of polyphenols (757.33 mg/100 g GAE) from the tested materials among the other extraction techniques (741.66 mg/100 g GAE). Likewise, green tea showed better performance than the rest and in solvents ethanol performed better as compared to their counter parts. Similarly, the isolates showed higher antioxidant potential as compared to their extracts and order of effectiveness was catechins > theaflavins > Ginger freeze dried extract (GFDE).

摘要

当前研究的目的是确定不同提取技术对绿茶、红茶和姜多酚的抗氧化能力的影响。最初，对原材料进行成分分析。然后，通过超声波和使用不同溶剂（即乙醇、甲醇和水）的常规溶剂提取方法从所有样品中提取生物活性部分。此外，通过溶剂分配法分别从绿茶和红茶中分离出功能成分，即儿茶素和茶黄素。此外，还使用各种分光光度法分析了提取物和分离物的总酚类和抗氧化特性。对于茶黄素和儿茶素的定量，使用了反相 HPLC 系统。结果表明，超声（P > .005) 证明在其他提取技术 (741.66 mg/100 g GAE) 中，从测试材料中提取和分离多酚 (757.33 mg/100 g GAE) 更有效。同样，绿茶表现出比其他茶更好的性能，并且在溶剂中乙醇的性能比它们的同类产品更好。类似地，与它们的提取物相比，分离物显示出更高的抗氧化潜力，有效性顺序是儿茶素 > 茶黄素 > 姜冻干提取物 (GFDE)。