Preliminary study on glucose oxidase-catalase enzyme system to control the browning of apple and pear purees

摘要

Oxygen is a key factory in fruit purees browning. The use of a commercial glucose oxidase-catalase enzyme system (GOX) for oxygen removal and browning control of Golden Delicious apple and Kaiser pear purees during storage has been investigated. The effect of ascorbic acid and peroxidase has also been tested and results compared with control (no treatment). Colour change was quantified using the CIE L*, a*, b* system. Heating has been the unique treatment able to control the enzymatic browning of fruit purees, whereas GOX was the most efficient in reducing to low level the dissolved oxygen content in apple and pear purees (99% oxygen removed), and showed an interesting capability to control the nonenzymatic browning during fruit processing and purees storage. However, ascorbic acid decreased the nonenzymatic browning of fruit purees to a larger extent than any other chemical treatment used in this study. The Kaiser pear shows a fast enzymatic browning thus may represent a good 'standard' to measure browning kinetics.