POLYPHENOLIC CONTENT, ANTIOXIDANT ACTIVITY, ENZYME INHIBITORY EFFECT AND SENSORY EVALUATION OF NOVEL COMPOSITE TEA

Abstract

Green tea is consumed all over the world and is well known for its health benefits. The nutritional profile of green tea can further be improved by adding other ingredients to it. Therefore, the objective of the present study was to evaluate the proximate and mineral composition, total phenolic content and antioxidant activity, inhibitory activity on α-amylase and α-glucosidase and sensory evaluation of a novel composite tea made from six different ingredients. The green tea was used as a control. Both the control and novel composite tea samples were first dried and then subjected to further chemical analysis. The proximate composition was assessed by following the procedure of Association of Official Analytical chemists. Mineral composition was analysed by using atomic absorption spectrophotometer. Total phenolic content was measured by using Folin-Ciocalteu method. Total flavonoid was determined by aluminium chloride colorimetric method. Antioxidant activity was examined by ABTS and DPPH method. The activity of tea samples on inhibition of α-amylase and α-glucosidase was measured by enzymatic method. Sensory score was evaluated by using 9-points hedonic scale. The results from the present study indicated that proximate composition including ash, fibre and protein content of novel composite tea were significantly (p < 0.05) higher than control tea. The concentration of macro and micro-minerals including Ca, Mg, K, Na, Fe, Zn and Cu of novel composite tea were also significantly (p < 0.05) higher compared to control tea. Total phenolic content, flavonoid content and antioxidant activity of novel composite tea were significantly (p < 0.05) higher compared to control tea. The results showed higher inhibitory action of novel composite tea against α-amylase and α-glucosidase enzymes when compared with control tea. There was no significant difference in sensory score in term of colour, aroma, taste and overall acceptability between control and novel composite tea. It is concluded from the present study that novel composite tea had maximum bioactive compounds and significantly inhibited the activities of α-amylase and α-glucosidase enzymes.