Extraction and clarification of apple juice with polygalacturonase obtained from apple (<i>Malus domestica</i>) fruits deteriorated by <i>Aspergillus niger</i>

Abstract

Pectinase is used commercially in the clarification and extraction of fruit juice from different fruit s. Green apples and Red apples obtained from the fruits section of a supermarket, Idiroko road, Ota were s urface sterilized and inoculated with Aspergillus niger . The stock culture was subcultured on Sabouraud Dextrose agar plates and 72-hr-old culture of Aspergillus niger served as the inoculum. The fruits were incubated for twenty-five days at room temperature (25 °C). Control fruits were similarly treated except that sterile inoculum was used for the inoculation. Extracts from the ino culated fruits exhibited appreciable polygalacturon ase activity while those from the uninoculated fruits p ossessed only traces of the enzyme activity. The polygalacturonase obtained after enzyme extraction was applied to freshly ripe apple fruits under cont rolled experimental conditions to investigate the role of polygalacturonase in the production of apple juice. The juice in the cylinder to which polygalacturonase was adde d was visually clearer and more than that with dist illed water. The optimum temperature of incubation for th e clarification of apple fruits with polygalacturon ase obtained from apple fruits deteriorated by Aspergillus niger was 25 °C. © 2011 International Formulae Group. All rights res erved.