Changes in the quality and recovery of pectin from fresh guava during its refrigerated and common storage

Abstract

The physiological losses in weight and the changes in the total pectin, water-soluble, oxalate-soluble and acid-soluble pectin in guavas picked at 2 stages of maturity (fully developed green and yellow fruits) stored at 47-50 degree F (relative Humidity 85-90 percent) and at room temperature (20-28 degree C) have been reported and discussed. The physiological losses in weight of green guavas stored at room temperature for one and two weeks were 18.8 and 20.2 percent respectively whereas the corresponding losses in weight during refrigerated storage were 3.9,6.8,9.9 and 12.0 percent after 1,2,3 and 4 weeks' storage of green guavas respectively. The losses in weight of yellow guavas were comparatively higher. At room temperature, the quality of pectin (as judged from methoxyl content and anhydrouronic acid content) deteriorated very rapidly (within 1 week), more so in the case of yellow fruits. The water soluble and oxalate-soluble pectin increased both in green and yellow fruits, (the increase being greater at room temperature), whereas the acid soluble pectin decreased. From the viewpoint of recovery and quality of pectin, fully developed green or yellow firm guavas could be kept at 47-50 degree F for 4 weeks. At room temperature, guavas could hardly be kept for a week.