Revestimento e filme biodegradável de gelatina de peixe e óleo de açaí: efeito da aplicação na qualidade pós colheita de tomate

Abstract

Tomato (Solanum lycopersicum) is a climacteric fruit that has a short post-harvest life due to biochemical reactions that accelerate maturation and senescence, affecting its quality. Biodegradable films have been studied as an alternative to minimize posthar-vest losses of fruits and prolong the shelf life of these foods. These coatings, when made with fish gelatin, have high water vapor permeability (PVA) and solubility due to their hydrophilic nature. And the addition of vegetable oils can improve these technological properties in addition to making the packaging active, acting as antioxidants and antimi- crobials. The aim of this study was to evaluate the influence of the addition of açaí oil on the technological properties of gelatin films and coatings and to apply the coating on tomatoes to preserve their postharvest quality. Gelatin extracted from fish skins had a yield of 18%, gel strength of 244g and melting point of 28 °C, important technological properties for this biopolymer to be used in the preparation of packaging. Two factorial planning were carried out to define the optimized conditions for obtaining the coating and the superimposition of graphics to define the conditions for the elaboration of the composite film. The coating with 5.40% gelatin, 17.25% açaí oil and 18.00% plasticizer showed the best responses for high viscosity and higher gel strength. The film with 5.40% gelatine, 21.50% açaí oil and 18.00% plasticizer showed the best responses for low water vapor permeability and high tensile strength. The PVA values obtained were 16.83x10-8 and 12.73x10-11 g.m-1. s-1. Pa-1 for control film (without oil) and composite (with oil), respectively. The composite film showed excellent results for the technological properties that are important for application to fruit. The optimized coating was efficient to maintain the quality characteristics of the tomatoes, as it reduced the percentage of mass loss and obtained a higher percentage of acidity compared to the control, proving that the coating with açaí oil was effective in delaying the ripening processes. It is concluded that the coating of fish gelatin and açaí oil extended the shelf life of tomatoes, being a promising alternative as a packaging for climacteric fruits.