Production of tannase by citrobacter freundii under solid state fermentation and its application in fruit juices debittering

S. Murugan¹*, P. Uma Devi², P. Mahesh¹, S. Suja² and K.R. Mani³

¹Post Graduate and Research Department of Microbiology,Dr. N. G.P. Arts and Science College, Coimbatore - 641 035 India.

²Post Graduate and Research Department of Biochemistry, Dr. N. G.P. Arts and Science College, Coimbatore - 641 035 India.

³Central Research Institute, Kasauli - 173 204 India.

Corresponding Author E-mail: micro_murugs@inbox.com 

ABSTRACT: Presence of high tannin contents in pomegranate and grapes are responsible for haze and sediment formation as well as colour, bitterness and astringency of the juice upon storage. Due to the inability of conventional fruit juice debittering process for removing the bitterness effectively, enzymatic debittering should be preferred. This present work is aimed at the debittering of pomegranate and grape juices using tannase, which has potential applications in degradation of tannins. The juice was treated with tannase 0.432Ug-1 at 37°C for two hour and then the enzyme was inactivated at 50°C for 30 minutes. Concentration of enzyme and the time of treatment also plays a crucial role in the debitterness. Tannase treatment resulted in 55% degradation of while a combination of tannase and gelatin (1:1) resulted in 60% of tannin degradation. Ascorbic acid, pH, total sugar, and protein content of both the treated and non-treated fruit juices were studied.

KEYWORDS: Pomegranate; grape; tannase; debittering; tannin degradation; ascorbic acid content

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