Development and characterization of edible films based on cashew gum associated to cellulose derivatives

Abstract

The development of technologies that retard the ripening process of fruits and vegetables has been established as an important resource to preserve the quality and extend the shelf life, especially one the tropical climate. In general, the fruits have high metabolic activity, especially after harvest, characterizing them as a highly perishable product. A viable alternative to the reduction of this activity is the use of biopolymers as edible coatings, which act as a barrier between non-toxic and biodegradable fruit and its surroundings. This work allows us to study the formulation of coatings prepared from cashew gum and a mixed derivative of cellulose, hydroxypropyl cellulose. The cashew gum is a renewable hydrophilic and biocompatible biopolymer. It is a complex heteropolysaccharide exudate with some filmogenic characteristics and low cost, which has been attributed to antimicrobial properties. The exudation of gum is a simple process and sometimes spontaneous occurring on the trunks and branch cashew. The harvest condition is done manually, and its composition is seasonal. Although the use of this favorable environment for the formation of gum films and coatings, the addition of a second polymer and in some cases small additions of plasticizers, it can generate a final product with better mechanical properties than the gum alone. Additionally, a lipid, stearic acid should be added into the films, thus reducing the hydrophilic character of these materials and consequently modifying the barrier properties, especially in relation to the permeation of water vapor. In this context, this work proposal aims to continue the ongoing studies with gum at Embrapa Instrumentação in São Carlos (São Paulo), developing films associated with hydroxypropylmethyl cellulose. The films will be initially processed by the technique of "casting" for characterization and subsequent evaluation of fruits high postharvest. (AU)