Pectin-degrading Enzyme Research Articles

This study was designed to observe chemical changes along with pectin-degrading and cellulolytic enzyme activities in two cultivars of guava during fruit maturation, ripening and storage. Total pectin content was 345. 9-396. 1mg/100g during maturation and 704. 8-804.0mg/100g in ripening in both cultivars. Protopection and water soluble pectin were predominant in matured and ripened fruits, respectively. Alcohol insoluble solids and acidity decreased in both cultivars; and pH was 4.2-5.0 in white and 4.0-5.2 in pink varieties during maturation, ripening and storage. Guava polygalacturonase and cellulase showed maximum activity at pH 5.5 and 6.0, respectively. Ripe guava showed polygalacturonase activity recognized only remarkably at full ripe and the activity increased further in stored samples. Guava indicated a little pectinesterase and cellulase activity and these were found to increase sharply at the stage from maturation to ripening. During the stages from immature to full ripe on the tree, ascorbic acid content increased gradually in both cultivars. During stages from ripe to full ripe, and storage for 10 days at 20°C; in white cultivar total ascorbic acid, ascorbic acid and dehydroascorbic acid contents were 149.9-273.5, 126.7-224.0 and 23.3-49.5mg/100g, respectively; and in pink cultivar these were 172.6-270.3, 146.2-203.8 and 26. 4-66.5 mg/100g, respectively. Ascorbic acid content was found to increase remarkably in stored fruits until decay or senescence of the fruits started.