Combined effects of enzyme dosage and reaction time on papaya juice extraction with the aid of pectic enzymes - A preliminary report

Pectic enzymes are widely used in the food industry for fruit juice extraction as well as in the clarification of cloudy juices. Our laboratory has been using pectic enzymes produced from a strain of Saccharomyces cerevisiae (ATCC 52712) in different applications including fruit juice extraction. The enzyme was produced in the laboratory by culturing the yeast in papaya juice supplemented with 1% pectin for 6 days. Known amounts of enzyme preparation (0-40 mg protein) were added to a measured weight of papaya mash for varying reaction periods (30-90 min) and the amount of free-run juice obtained in each treatment compared with a control sample. Treatment of 200 g of papaya mash with different dosages of the pectic enzyme extract resulted in rapid increases in flow rate of free-run juice. Mash treated with 32 mg of total protein extract with a 30-min reaction time was the optimum for a maximum rate of juice flow (25 mL/min) when initial rates were measured. There was no significant difference (P > 0.05) between the red- and yellow-fleshed varieties of the papaya used. When juice flow was monitored over 6 min, the treated samples gave a flow rate that was more than twice those of the untreated samples. This biotechnological approach could be adopted to enhance papaya-juice production by local fruit juice processors when parameters for scale-up processes are established.