Application of Enzymes in Fruit Juice Technology

The three essential mechanisms underlying enzyme application are:

1. 1. the mechanism of enzyme activity, which is based on the interaction of three parameters: enzyme concentration, application temperature and reaction time. These parameters can be varied within certain limits to suit processing operations.
2. 2. the mechanism of pectin degradation, which largely depends upon the type of enzymes used and the pectic composition of the substrate(s). Enzymes can be selected to attack preferentially specific pectic substances present. The substrate’s own composition governs whether its viscosity increases or decreases during enzymic treatment, depending on the relative percentage of soluble to insoluble pectin therein. Accurate application of these factors is essential to achieve the desired goal.
3. 3. the mechanism of clarification, which takes place in three distinct successive phases: destabilisation, coagulation and sedimentation. Their neglect or recognition determine failure or success.

Mash treatment technology is described for using pectinases in conjunction with cellulases and hemicellulases to produce pulps, nectars, turbid or clear juices and their concentrates from raw materials including apples, pears, stone-fruits, berries, grapes, citrus fruits and vegetables. Clarification technology using pectinases in conjunction with amylases, proteinases and several other complementary enzymes is explained—from viscosity reduction prior to concentration of stable turbid juices, right through to the stabilisation of clarified juices to prevent haze formation and sedimentation in the finished products.

Finally an appreciation is given of the possibilities for comparison of various enzyme preparations.

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