Comparison of microwaves and conventional thermal treatment on enzymes activity and antioxidant capacity of kiwifruit puree

Abstract

Enzymes are naturally present in food and can cause product deterioration. For this reason,most food-processing steps try to reduce the enzymatic activity. The aimof thisworkwas to compare, in terms of both the inactivation of kiwifruit puree peroxidase, polyphenoloxidase and pectinmethylesterase and also themaintenance of the antioxidant capacity of the product, the effect of a microwave treatment with a conventional thermal treatment designed to cause the same level of peroxidase inactivation (90%). The microwave power and process time that best permitted the maximisation of both the enzyme inactivation and the antioxidant capacity of the product, were selected by means of the Response Surface Methodology. The results obtained point to microwave heating as an appropriate technology with which to produce a stable kiwifruit puree, since these treatments were more effective at enzyme inactivation and antioxidant capacity retention than the conventional thermal treatment.