Desenvolvimento de bionanocompósitos e aplicação na conservação de mandioquinha-salsa

Abstract

The biocomposite starch has low mechanical strength and low barrier to gases, light and moisture, these parameters essential for the preservation of food products. The properties can be improved by the incorporation of nanometric fillers lignocellulosic, i.e nanocellulose.The agroindustrial waste, abundant in nature, have been used to produce nanocelullose due to low cost and high cellulose content. In this work, the objectives were the development of bionanocomposites cassava starch with cellulose nanocrystals produced by hydrolysis of waste from the processing of coffee and rice husks and application in conservation Peruvian carrot.The wastes were subjected to chemical treatment for purification of cellulose, and then subjected to acid hydrolysis for the production of nanocrystals. The fibers were hydrolysed with sulfuric acid 50% for 75 minutes at 50 °C. Waste and nanocrystals were subjected to chemical, physical and morphological analyzes. The nanocrystals were used to develop bionanocomposites in cassava starch matrix by casting process and these were characterized with respect to mechanical strength, elongation at break, thickness, opacity, water solubility and permeability to water vapor. The results showed that it is possible to obtain cellulose nanocrystals by the technique used. The cellulose nanocrystals from the coffee processing waste did not affect the mechanical strength and elongation of starch biocomposites, increased permeability to water vapor and reduced solubility. The cellulose nanocrystals rice husk increased elongation at break and reduced water vapor permeability and solubility. The opacity of both bionanocompósitos was unchanged. Bionanocomposites dispersions were used as coating roots Peruvian carrot, which were stored for eight days and analyzed. Analysis of pH, soluble solids, weight loss, color and firmness were made every two days for eight days of storage, to check the influence of the coverage on these properties. Significant difference was observed between treatment and storage time for firmness, pH, soluble solids and titratable acidity of the roots coated. The bionanocomposites made with cellulose nanocrystals assist in maintaining the firmness of Peruvian carrot roots during storage.