Avaliação de coberturas comestíveis à base de quitosana e curcumina na qualidade pós-colheita de uvas benitaka

Abstract

Due to the fragility and difficulty in grapes deterioration prevention which have a high postharvest loss the use of edible coatings is proposed with the addition of antimicrobial function to prolong grapes shelf life. In this work Benitaka type table grapes were evaluated in relation to texture, weight loss and microbiological quality (molds and yeasts) for 7 days of storage room temperature at 25 ° C and 51% of relative humidity. A control sample (C) (sanitized) and two edible coatings were applied to Benitaka grapes: chitosan film (Q) and chitosan film added of zein nanoparticles with encapsulated curcumin (QC 15mg/mL of filmogenic solution). Curcumin, recognized by its antimicrobial properties, was encapsulated by nanoprecipitation in zein with the intent of increase its solubility and dispersibility in water since it has a lipophilic character. The nanoparticles were added to the chitosan edible coating and successfully applied to Benitaka grapes. Both edible coatings (Q and QC) led to higher fruit weight loss (up to 10.45%) than the control sample (4.72%) after 7 days of storage. Possibly this behavior was due to the loss of water present in the chitosan matrix. The texture profile of grapes showed a significant difference (p <0.05) for the hardness parameter (firmness) indicating the formation of a harder coating during the storage time due to dehydration of chitosan film. The microbiological quality of Benitaka grapes, with respect to molds and yeasts, indicated that the coated samples until the third day of storage were considered safe for consumption (<10 CFU/g), but after the seventh day not (above 1.33x106 CFU/g), according to the limit indicated by law.