Characterization of Apple Juice Clarified by Tannase from Serratia marcescens IMBL5 Produced using Agro-industrial Waste Materials

Abstract

In the present study, clarification of apple juice with tannase from S. marcescens IMBL5 produced using various agro-waste materials was carried out. Sugarcane bagasse was found to be the most suitable source for the augmented production of tannase enzyme by response surface methodology with the temperature at 40 °C, pH 4.5 and the incubation period of 96 hrs. The enzyme was quantified and partially purified through protein precipitation. The partially purified tannase with gelatin clarified about 62% of the apple juice in 3 hr of incubation at room temperature and it was gently increased with the incubation period. The detannification was characterized by estimating tannin content of the clarified juice. The amount of total reducing sugar in the juice was increased almost 50 % after 5 hours of incubation period. FTIR spectrum of the clarified juice revealed that the conformational changes that occurred in the functional groups. The spectrum absorptions between 500 and 1700 cm-1 mainly reflected the C=O stretch of the pectins and acids and C–O modes of the carbohydrates that correspond to the absorption zones of the sugars. The HPLC analysis of the clarified apple juice indicate the presence of phenolic compounds and sugar derivatives such as gallic acid, catechin, caffeic acid, epicatechin, glucose and sucrose which confirms the quality and clarity of the apple juice using the tannase enzyme.