Quality, antioxidant activity and composition of Indian black teas.

A comparative study was undertaken to determine
the difference in quality, antioxidant activity, and
mineral content of northern and southern Indian tea varieties.
The results showed that the antioxidant activity,
theaflavin and thearubigin content, color particle size and
total soluble solids influence the tea leaf and tea dust.
Assam leaf showed higher values for all the physicochemical
properties followed by Darjeeling leaf. In addition,
the mineral composition of the tea infusion was also
influenced. The preparation method, including the amounts
of tea and water used, infusion time was shown to be a
major determinant of the component concentrations of tea
beverages as consumed. An illustration of the variation
introduced by these varieties of tea is provided by comparing
solids, caffeine, minerals and antioxidant activity of
black teas available locally.