Changes related to softening of soursop during postharvest maturation

Abstract

This work aimed to evaluate the physical, chemical and biochemical changes related to softening during maturation of Crioula soursop fruit (Annona muricata L.). Fruits were harvested at the physiological maturity stage from plants grown at Embrapa Agroindústria Tropical Experimental Station, in Pacajus, CE, Brazil, and were stored at 26.3±0.6ºC and 88±12% relative humidity, during 1, 2, 3, 4 and 5 days. A completely randomized design was used with four replicates. The following variables were evaluated: weight loss; starch content; total and soluble pectin content and enzymatic activity of amylase, pectin methylesterase, polygalacturonase and alfa- and beta-galactosidases. There was no significant variation in the soluble pectin content. Weight loss reached 5% in the fifth day, without causing fruit shriveling. Reductions on starch and on total pectin contents occurred in the period of great enzymatic activity, respectively, of amylase and of polygalacturonase, and cell wall beta-galactosidase. The most significant changes on the contents of starch and total pectin, on pectin solubilization and on the activity of the enzymes amylase, pectin methylesterase, polygalacturonase and cell wall beta-galactosidase occurred from the second to the fourth day after harvest.