Filmes e revestimentos comestíveis de amido à base de fontes não tradicionais e aplicações em goiabas 'paluma'

Abstract

The use of coatings for fruits aims to mimic the natural cuticular barrier, aiming at reducing respiration through gas exchange with the medium, delaying its senescence, contributing to post-harvest conservation. Guava fruits still suffer from obstacles in the market, due to their perishability, requiring the use of technologies that enable their conservation in the post-harvest. The present work aimed to extract, characterize starch-based films from non-traditional sources and use in the application as edible coatings in guavas 'Paluma'. The extraction was performed in three sources of non-traditional starches: avocado, pitomba and red jambo seeds. From the starches were characterized 6 formulations of filmogenic solutions in obtaining the films. The best identification of the filmogenic solutions with the best potentials for coatings were used as coatings in the 'Paluma' guavas. The guavas were immersed in three formulations of the filmogenic solution and one control and packed in expanded polystyrene trays and coated with polyvinyl chloride film, during a period of 12 days (0, 3, 6, 9 and 12), under ambient conditions, evaluated for subjective appearance, physical and physicochemical characteristics. The design was completely randomized, where for the six biofilms were obtained by the casting technique, with 3 replicates of 1 petri dish/plot. The data obtained were submitted to analysis of variance by the F test and the means will be compared by Tukey's test at the level of 5% probability. For the storage of guavas with the coatings, a 4 x 5 factorial scheme was performed, with 3 replicates of approximately 200 grams of the fruit/tray, totaling 60 experimental units. According to the results obtained, it can be said that the films elaborated of avocado and jambo starches for both concentrations presented water activity contents below 0.60 and can be considered stable during storage and microbial risk; The parameter L* indicated that all films presented good luminosity, greater transparency and good proposals for use as coatings. At the end of the storage period, the fruits of the treatments with avocado, jambo and pitomba coating were between scores 7 and 9, that is, they presented fresh product, turgid, surface presenting brightness, color with breakdown of yellow pigmentation, absence of stains or diseases and damage and/or rot. It was observed that until the 6th day of storage, the treatments with coating obtained better maintenance of the vitamin C content, when compared to the control. It was evidenced that the coatings presented excellent performance in the post-harvest conservation of 'Paluma' guavas stored for 12 days under ambient conditions, preserving their quality and the integrity of the fruits, keeping them turgid, with an attractive appearance for a longer period.