Optimization of an Enzyme Assisted Process for Juice Extraction and Clarification from Litchis (Litchi Chinensis Sonn.)

Abstract

Litchi pulp was treated with various concentration levels of hydrolytic enzymes viz. pectinase (0-0.133%w/w), cellulase (0-0.266%w/w) and hemicellulase (0-0.20%w/w) for different durations (30-150 min) at 45°C. The effect of enzyme treatment conditions was studied on yield, clarity, apparent viscosity and total soluble solids (TSS) of juice obtained from the pulp. The optimum process conditions were determined by employing a second order central composite rotatable design in combination with response surface methodology. Yield, clarity and TSS of juice were found to increase and apparent viscosity was found to decrease significantly by enzymatic treatment. The optimum conditions for enzymatic treatment of pulp obtained after a 2 sided desirability function with the responses juice yield, clarity and TSS to be maximized and viscosity to be minimized were 0.076% (w/w) pectinase, 0.138% (w/w) cellulase, 0.107% (w/w) hemicellulase and incubation time of 106.5 min. The predicted values for juice yield, clarity, viscosity and TSS under optimized conditions were 77.19 %, 93.53%, 1.359mPa s and 19.68°brix which showed a good agreement with the experimental values under the same set of conditions.