Production of tannase under mSSF and its application in fruit juice debittering

Abstract

Enzymatic treatment of fruit juices to reduce the bitterness has got advantages such as the higher quality of juice due to the lower haze and non-deterioration of juice quality. The pomegranate has recently been acclaimed for its health benefits, in particular, for its disease-fighting antioxidant potential. Presence of high tannin content in the pomegranate is responsible for haze and sediment formation as well as for colour, bitterness and astringency of the juice upon storage. Due to the inability of conventional fruit juice debittering processes for removing the bitterness effectively, enzymatic debittering should be preferred. This present work is aimed at the debittering of pomegranate juice using tannase, which has potential applications in the degradation of tannins. The juice was treated with tannase (10% v/v) of 35.6 U/mL at 37oC for two h and then the enzyme was inactivated at 50°C for 30 min. Tannase treatment resulted in 25% degradation of tannin while a combination of tannase and gelatin (1:1) resulted in 49% of tannin degradation. Ascorbic acid content, pH, total sugar, protein, and viscosity of both the treated and non-treated fruit juices were studied.