Clarification of mango juice by Aspergillus niger cellulase using response surface methodology

Ripe mango juice is viscous and cloudy in nature, which warrants the use of commercial enzymes for clarification, a major factor that contributes for increase in production cost to the juice processing industry. Use of low cost substrate such as mango processing waste for enzyme production is a recent strategy to minimize the cost of juice production. Cellulase complex with specific activity 2.6 U/ml comprising of the isoforms, viz., CMCase and α-glucosidase, produced by Aspergillus niger using mango peel waste as the substrate in our earlier study, was used for mango juice clarification and the process parameters were optimized using response surface methodology. The dependent variables like colour, viscosity and juice yield were recorded. Based on the response surface plots, 0.1% enzyme concentration, 40°C temperature and 30 min incubation period resulted in increased juice yield (from 8.935 to 14.135 ml), colour in terms of light transmittance (86.664 to 93.364 L) and reduced viscosity (5.766 m Pa.s to 0.328 m Pa.s). Under the proposed optimized conditions the determination coefficient (R²) for juice clarification was equal to 0.72 indicating that the model could explain 72% of the total variation as well as establish the relationship between the variables and the responses. The three dimensional plots confirmed the interactions among the parameters.