Application of a Pectin trans-Eliminase Preparation to Fruit Juices

Abstract

Application of a pectin trans-eliminase preparation from Asper gillus japonicus to fruit juices was investigated. A small amount of pectin trans-eliminase was enough for the complete clarification of an apple juice, but a considerable amount of the enzyme was necessary for clarification of grape juice. Optimal conditions of pH and temperature for clarifying fruit juice were pH 3-4 and around 50°C. However, slight differences in the effect of pH and temperature on fruit juice clarification were seen between apple and grape. When pectin trans-eliminase activity of several preparations obtained from this mold was adjusted to the same level, the ability of clarifying an apple juice was almost same, but that of clarifying a grape juice varied widely. These results suggest that unlike apple juice clarification, other enzyme(s) in this preparation may play a role in the grape juice clarification.Pectin trans-eliminase preparation was effective on the fittration of crushed grapes resulting in the increase of yield(about 11%)and the improvement of filterability of the juice.