Development of Pectinase Preparation for the Making of Orange Juice : 2. Clarification Activities of Pectinase Preparations on the Citrus Juices, and the Relationship between Polygalacturonase and Pectinesterase for its Clarifying Activity

The clarification of natural juice has been studied using commercial Pectolytic enzymes produced by Coniothyrium diplodiella and Aspergillus niger. Commercial pectolytic enzymes contains polygalacturonase and pectinesterase. These two enzymes could not cause the clarification of citrus juice alone, whereas a mixture of them was capable of clarifying the juice almost completely. The clarifying activity of an enzyme preparation depended on the activities of polygalacturonase, pectinesterase and the ratio of these two enzymes. On the juice of Mandarin orange, the clarifying activity of the enzyme preparation was effectiveness in the ranges of PG=90 Pgu, PE=60 Peu, and the ratio of PG/PE=O.6. The increasing of this value of PG/PE improved the clarification. The clarifying activity of the enzyme preparation on the juice of Natsudaidai was very limited in the range of PG/PE=1.6～3.1, and was also required above the level in the activities of PG=280 Pgu and PE=175 Peu. On this reason, we could be understand that it is very difficult to developing of more effective pectinase preparation for the clarifying of Natsudaidai juice.