Obtención de plástico biodegradable a partir del almidón de fréjol negro (Phaseolus vulgaris L.) para envoltura de alimentos

Abstract

The aim of this research work is to obtain a biodegradable plastic from black beans starch (Phaseolus vulgaris) in order to be used in food packaging. The starch was extracted by means of the wet method using a 2k factorial design of 2 variables, revolutions per minute and time, giving as a result that T2 treatment was the best with a yield of 26.07 and in the analysis of variance ANOVA, there is no significant difference, then, the physicochemical characterization of starch was carried out following the INEN 1456 standard, where results obtained were within the established standard, the microbiological tests were carried out in an external laboratory, while the percentage of amylose and amylopectin resulted (21.09-78.91). To obtain bioplastic, tests were carried out to determine the adequate formulation with the 2k factorial design of 4 treatments with 4 repetitions, the concentration of glycerin and starch was manipulated with 2 variables. The best biodegradable plastic was TP2FN with a concentration of starch (2g), glycerin (0.5ml) distilled water (30ml), acetic acid (4ml).This formulation led us to the following results of the physicochemical and mechanical analysis: the thickness of (0.06 mm), moisture (19.6%), solubility in water (32.81) and permeability to water vapor (2.94427E- 06). Regarding the tensile tests of the bioplastic sheet, based on the standard (INEN 2635, 2012) a modulus of elasticity of 2.38E + 01 MPa was obtained, maximum stress 5.02 MPa; In addition, the biodegradability of plastic in 28 days in the environment (43.55%), in water (84.13%), for plastics on land in a period of 12 days (91.3%), which indicates that the material obtained can be used as a food wrap as it meets with the parameters established in the corresponding standard.