optimization of kiwifruit juice clarification using pectinase enzyme, bentonite and polyvinyl polypyrolidone

in order to prevent the turbidity during storage of kiwifruit juice, clarification is necessary. through proper clarification, flavor and taste of the product is also improved. therefore, the purpose of the present study was to present a method to determine the optimum amount of clarifying agents (pectinase enzyme, bentonite and polyvinyl poly pyrolidone) for producing kiwifruit juice with stable clarity. for this purpose, effect of pectinase enzyme (2-8 g/kg), bentonite (200-350 g/ton) and polyvinyl poly pyrolidone (70-110 g/100 lit) on viscosity, turbidity, clarity and total phenolics compound of kiwifruit juice was investigated. for each response a second order polynomial model was developed using a multiple linear regression analysis. results showed that r2 for viscosity, turbidity, clarity and the total amount of phenolics were more than 0.90. the statistical analysis indicates that viscosity, turbidity and clarity (p<0.01) were significantly correlated with enzyme, bentouite and pvpp. the effect of pvpp concentration on the total phenolics were reported to be significant (p<0.01). with regard to the experimental model obtained through response surface methodology, the relationship between the variables studied was appropriate. the final optimal amounts of clarifying agents under simultaneous consumption condition were reported as follows: pectinase enzyme, bentouite and pvpp were specified 5.83g/kg, 306.05 g/ton, and 70g/100 lit, respectively.