Abstract:
Different enzyme treatments have been invented to improve the clarity of cold-watersoluble instant black tea. This research was conducted to study the effects of different
enzyme treatments on the catechin and caffeine contents of cold-water-soluble instant
black tea. Samples of black tea extract were separately treated in triplicates with different
combinations of Viscozyme, Tannase, and Protease enzymes at previously optimized level
(0.3% wt/wt, based on tea solid in tea extract) at 40°C for 40 min. Samples were heated to
90°C and cooled to room temperature. Then they were centrifuged at 3500 rpm for 10 min
and supernatants were analyzed for catechins and caffeine contents by High-Performance
Liquid Chromatography. Data were subjected to Analysis of Variance and mean separation
(p<0.05). Tannase can degallate gallated catechins releasing gallic acid and degallated
catechins. Viscozyme hydrolyzes carbohydrates releasing constituents complexed with it.
Therefore, samples treated with a combination of Tannase and Viscozyme contained a
significantly higher amount of gallic acid (306.7±35.1 µg ml-1
) than the other samples and
this sample contained a significantly higher amount of Epigallocatechin (72.5±5.7 µg ml-1
)
and Epicatechin (89.2±8.4 µg ml-1
) than the control and samples treated without Tannase.
Moreover, samples treated with Tannase contained significantly higher amounts of total
catechins and caffeine than the other samples. Catechins and caffeine positively affect the
organoleptic properties of tea infusion. It can be concluded that treatment with a
combination of Viscozyme and Tannase will enhance the catechins and caffeine contents
of cold-water-soluble instant black tea.
.
Keywords: Cold-water- soluble instant black tea, Viscozyme, Tannase, Protease, Catechins
