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Abstract
Pectin rich fruit juices need enzymatic treatment for clarification. As fruits are rich in pectin, pectinolytic treatment can efficiently reduce viscosity resulting in clarified fruit juice. Enzymatic treatment of mango pulp results in 80% recovery of total juice present in the fruit. Use of pectin degrading polygalacturonases increases both fruit juice extraction and clarification. Polygalacturonase (PG) produced by Aspergillus awamori MTCC 9166 is studied for mango juice clarification and conditions are optimized by Box-Behnken design. The conditions studied are incubation time (15-45 min), enzyme concentration (0.5-1.5 U/ml), and temperature (25-400C). Significant regression model describing the change on viscosity with respect to independent variables was established. Based on surface plots and contour plots, the optimum conditions for mango juice clarification were obtained. The recommended enzymatic treatment conditions are enzyme concentration 1.5 U/ml, incubation time 30 min at 400C. Significant (60%) reduction in viscosity was observed.
Article history
Received: 16 December 2014
Received in revised form: 27 April 2015
Accepted: 23 June 2015
Keywords
Aspergillus awamori MTCC 9166
Mango juice clarification
Box-Behnken design
Polygalacturonase
Introduction
Mango is one of the important fruits widely grown in tropical countries and is indigenous to India. The best quality mangoes originate in southern part of India. It is perishable, seasonal fruit which is rich source of pectin and also contains sucrose, glucose and maltose. Pectic substances and pectinolytic enzymes play important role in fruit juice processing (Fogarty and Kelly, 1983). Enzymatic treatment of mango mash results in 80% of total juice present in fruit. Pectinases along with cellulases and xylanases are used to degrade mango pulp (Kashyap et al., 2001).
Pectinases play important role in processing plant materials to food products, such as de-pectinization of fruit juices, maceration of vegetables and fruits, and extraction of vegetable oils (Benen et al., 2003). Pectinolytic enzymes are used in fruit processing industry to increase yields, improve liquefaction, clarification and filterability of juices ( Harsha et al., 2014). Commercial sources of fungal pectinases have been used in fruit juice processing since 1930's for clarifying fruit juices and disintegrating plant pulps to increase juice yields (Macmillan and Sheiman, 1974). Most enzymes are marketed on the basis that they are generally recognized as safe (GRAS) for their intended use in the juice process (Grassin and...