文章基本信息

标题：Effect of Citric Acid on the Total Monomeric Anthocyanins and Antioxidant Activity of Liquor Made from Unprocessed Purple Leafed TRFK 306 Kenyan Tea Clone
本地全文：下载
作者：Emily C. Kilel ; John K. Wanyoko ; Abdul K. Faraj 等
期刊名称：Food and Nutrition Sciences
印刷版ISSN：2157-944X
电子版ISSN：2157-9458
出版年度：2019
卷号：10
期号：10
页码：1191-1201
DOI：10.4236/fns.2019.1010086
语种：English
出版社：Scientific Research Publishing
摘要：A study was conducted to find out the effect of citric acid on total monomeric anthocyanins and antioxidant activity of liquor made from unprocessed purple-leafed TRFK 306 Kenyan tea, brewed at various time/temperature combinations. Most purple tea consumers usually brew the tea leaves then add some lemon juice before consuming it. Citric acid was used here to mimic the use of lemon juice. Documentation on the quality of such a brew is scanty and the effect of acid on its quality is equally scanty. The current study used brewing time/temperature combinations of 5, 10 and 15 minutes with 70°C and 92°C drinking water. Total monomeric anthocyanins were analysed using UV-1800 spectrophotometer (Shimadzu, Japan) while DDPH method was used to assay for antioxidant activity. Citric acid concentration of 0, 0.1% to 0.5% was used to check their effect on the brews with the highest total anthocyanins and antioxidant activity. The results showed that brewing temperature of 70°C had 9.5 mg/L to 27.7 mg/L, with 5 minutes brewing time being the highest. Temperature of 92°C had 37.5 mg/L to 92 mg/L with 5 minutes brewing time having the highest total monomeric anthocyanins. Antioxidant activity of 92°C brewing temperature ranged from 90.7% to 92.0%. Total monomeric anthocyanins increased with increased citric acid concentration up to 0.3% before it decreases while for antioxidant activity, it decreased with addition of citric acid. It was concluded that for maximum anthocyanins extraction, 5 minutes brewing time is the best while ten minutes brewing time could give optimum antioxidant activity.
关键词：TRFK 306;Total Monomeric Anthocyanins;Antioxidant Activity;Citric Acid;Brewing Conditions