PROTEIN EXTRACTION DURING PRODUCTION OF VARIETALLY DERIVED APPLE JUICES USING A MASCERASE ENZYME

The extraction of protein into apple juice under non-oxidative conditi ons, following Pectinex Ultra SP digestion of the cell wall and middle lamella, was assessed using Kjeldahl crude protein (Nx6.25) and SDS-P AGE. Granny Smith, Red Delicious and McIntosh apples gave increased le vels of juice protein (P less than or equal to 0.05), while Golden Del icious and Spartan juice protein was not significantly increased. Juic e proteins gave characteristic patterns on SDS-PAGE, especially Granny Smith proteins which displayed a unique doublet just below a major ba nd at 29 kD. The increase in protein detected by protein analysis was seen in SDS-PAGE as a large increase in proteins with molecular weight s less than about 30 kD. (C) 1997 Department of Agriculture and Agri-F ood. Published by Elsevier Science Ltd.