Phenolic Content and Characterization of Tea Shrub Bottom Leaves

Abstract

Background: Tea polyphenols are extracted from top two-four young leaves and leaf buds of tea plant, while the bottom leaves of tea shrub are considered as an agricultural waste. Hence, an attempt has been made to utilise them as an alternate source of low-cost natural antioxidant. Methods: Green tea shrub bottom leaves of Camellia sinensis Var. assamica /TV-23 were procured from Estate-Seni Mora Bagan, Karanga kamar, Hazarika Gaon, Tal. Karga, Dist. Jorhat, Assam. Proximate analysis, total phenolic (Folin-Ciocalteau) and qualitative analysis (Agilent LC-MS system) for phenolic compounds including antioxidant properties was carried out using standard analytical methods. Result: The results for proximate content were protein (14.43%), lipids (4.44%), total ash (4.94%), crude fibre (33.63%) and moisture (3.20%). A total phenolic content of dry green tea powder extracts prepared by using ethanol was 105.68 mg GAE/g dry tea powder. Total 12 different bioactive compounds were identified by HR-LCMS. The antioxidant properties were DPPH (89.82%), ABTS (74.71%), FRAP (1053.92 µ mol Trolox/gram dry tea powder) and metal chelating activity (17.51%). Based on the study it is opined that; tea shrub bottom leaves can act as a promising source of low-cost tea polyphenols when extracted with ethanol as a solvent for value added fish product shelf life extension.