Produção e caracterização de filmes poliméricos para revestimento comestível em goiabas

Abstract

The polymeric blends have emerged as a way to obtain new materials with better properties and features quickly and cost-effectively. The goal of this work is to characterize and crosslinking polymeric films formed by sodium carboxymethyl cellulose (CMC), xanthan gum (GX) and polymeric blend GX/CMC, in addition to evaluating the behavior of guavas coated with these compositions at room temperature, trying to identify the best alternative for the production of edible coatings in order to increase the shelf life of fruits. It was evaluated the effect of crosslinking agent, citric acid (AC), in relation to the water resistance of the films (solubity, swelling, permeability to water vapours). The values of pH, oBrix, total titratable acidity (ATT), visual sensory analysis and analysis of moulds and yeasts in the days of treatmente 1, 4, 6, 8 of the guavas studied, besides tests of biogegradability of the films in the soil, shows that the environmental impact caused by these films is minimal. The reticulated films showed good resistence to water solubility. The GX/CMC/AC film presented the best property of the water vapour barrier (0,63x10-8 g s-1m-1Pa-1) and swelling degree (495.76 %). There was a tendency to increase the pH of the samples of guavas in all treatments. At the end of the storage, the pH of the samples submitted to the control treatment (4.32) was superior of the others: CMC (3.74), GX/CMC (3.75) e GX (3.92). oBrix results have shown that the fruits covered showed a slower ripening. The uncoated guavas showed lower values of total titratable acidity. The treatmente that presented the lower count of yeasts and moulds at the end of day 8 was the polymeric blend. It can be concluded that the study of edible coating on fruits is relevant since they were obtained better results. Keywords: polymeric films; xanthan gum; carboxymethyl cellulose; co