Effects of raw material on the chemical composition, organoleptic properties, antioxidant activity, physical properties and the yield of instant black tea

摘要

Effects of dhool (particles resulting from rolling of green leaf) fermented for varying durations, black tea and the rejected fraction in black tea manufacture which is known as 'broken mixed fannings' (BMF) as raw materials on the physicochemical and organoleptic properties of instant black tea were studied. Total polyphenols and theaflavins contents of instant black teas prepared by using fermented dhools (38.4-40.1 g/100 g and 1.05-3.10 g/100 g respectively) were significantly higher than those of instant black teas prepared by using black tea (35.2 g/100 g and 0.37 g/100 g) and BMF (33.5 g/100 g and 0.28 g/100 g). Further, trolox equivalent (TE) antioxidant activities of instant black teas prepared by using fermented dhools (542-564 TE mg/g) were significantly higher than those of instant black teas prepared by using black tea (488 TE mg/g) and BMF (341 TE mg/g). Type of raw material did not affect significantly on the yield and fluoride and aluminium contents of instant black tea. Chemical composition, organoleptic properties, antioxidant activity and physical properties of instant black tea can be improved by using dhool fermented to 2-21/2 h as raw material. (C) 2015 Elsevier Ltd. All rights reserved.