New edible coatings composed of galactomannans and collagen blends to improve the postharvest quality of fruits - Influence on fruits gas transfer rate

摘要

The objective of this work was to produce new edible coatings, based on a mixture of galactomannans from novel sources (seeds of Adenanthera pavonina and Caesalpinia pulcherrima), collagen and glycerol, and to determine their influence in gas transfer rates when they are applied on mangoes and apples. The first part of the work consisted in obtaining coating solutions with the convenient values of wetta-bility for each fruit; such coating solutions were then characterized in terms of their permeability (to CO_2, O_2 and water vapour), mechanical properties, colour and opacity. Gas transfer rates from mangoes coated with a solution of A pavonina gaiactomannan (0.5%), collagen (1.5%) and glycerol (1.5%) were compared with those of mangoes without coating: 28% less O_2 consumption and 11% less CO_2 production were observed in coated mangoes. The same procedure was performed in apples (in this case using C. pulcherrima gaiactomannan (0.5%), collagen (1.5%) and no glycerol); the CO_2 production and the O_2 consumption was approximately 50% lower in apples with coating than in apples without coating. The results suggest that these coatings can reduce gas transfer rates in these fruits, and can be therefore important tools to extend their shelf life.