Clarification of Guava (Psidium Guajava) Fruit Juice using Multi-Enzyme (Pectinase, Cellulase and Hemicellulase) Treatment: Optimization of Processing Parameters

Abstract

Clarified juices are making remarkable place in the market as these are preferred by a significant portion of the population apart from making ready to serve drinks, clear juice cocktails, cordials, clear nectars, translucent jelly products, candies, clear juice blends, etc. from it. There exist several market opportunities, not only for the traditional clear juice from apple, but also for clarified juices produced from fruits with high pulp content. This study was carried out with an objective of producing high quality clarified guava juice with high yield by multi enzyme system. Guava juice was treated with various concentration levels of commercial enzymes pectinase, cellulase and hemicellulase for different incubation periods (30-150 min) at 55 0C. The effect of treatment conditions was studied on turbidity and yield of clarified juice obtained for each enzyme separately and optimum process conditions were determined. Based on these findings guava juice was given simultaneous treatment of all three enzymes with compromised process conditions (Pectinase 1.00%, Cellulase 0.50%, and Hemicellulase 0.80% with 90 min incubation time at 55 0C) which produced clarified juice with turbidity 18 NTU and yield 62%. Response Surface Methodology (RSM) employing a second order central composite design was used to obtain optimum process conditions for simultaneous treatment with the range of variables for enzymatic treatment conditions (Enzyme concentration: 0.20-1.40% w/w, 0.20-0.80% w/w and 0.20-1.00% w/w for pectinase, cellulase and hemicellulase respectively, Incubation time: 30-150 min and Incubation temperature 55 0C) based on previous individual experiments, which showed results very close to that obtained in previous experiments giving the optimum values as 0.96%, 0.57% and 0.77% enzyme concentration for Pectinase, Cellulase and Hemicellulase respectively, and incubation period of 99 min at incubation temperature of 55 0C. Under this condition, the juice was obtained with turbidity value as 17 NTU and 64.7% of yield.