Síntese e aplicação de revestimentos à base de fécula, quitosana e cera de carnaúba na conservação pós-colheita da banana

Abstract

Packaging is fundamental for the conservation of food, contributing to the preservation of organoleptic and nutritional properties. However, non-biodegradable packaging represents a serious environmental problem. Also, many packages are produced with materials from nonrenewable sources such as petroleum. Therefore biopolymer films and coatings are a good alternative because they are biodegradable, non-toxic, non-harmful to the environment and obtained from renewable sources. The present work investigated the preparation and characterization of biopolymer films based on manioc starch (0-3%), chitosan (0-3%), carnauba (0; 0.2%) and glycerol (0.6%) wax (3% starch, 0.2% carnauba wax and 0.6% glycerol) and 2c (2% starch, 1% chitosan) were used to determine the composition with the best barrier properties. The films 1c (3% starch, 0.2% carnauba wax and 0.6% glycerol) and 2c (2% starch, 1% chitosan, 0.2% carnauba wax and 0.6% % glycerol) were chosen because they presented lower values of TPVA, attributed to the incorporation of carnauba wax, which reduced their permeability by around 20% in relation to films without wax. In a second stage bananas cv. 'Williams' were covered with pre-selected coatings. During 15 days of storage at 20 ° C and relative humidity of 90%, the effects of the application of these coatings on various chemical, physical and physiological characteristics of the fruits were evaluated in comparison with a control group, besides, on the 15th day, sensory and purchase intention evaluation with several randomly chosen interviewees. Both coatings were shown to be able to significantly reduce the respiration rate of banana cv. 'Williams', altering their metabolism, reducing the loss of mass and delaying several changes due to senescence, such as decrease in pulp firmness, color change and amount of sugars. Sensory and purchase intention analysis revealed that fruits treated with Coating 2c presented better overall appearance, better conservation status and reached the highest purchase intention indices