Development and characterization of biodegradable films from fermented yam (Dioscorea trifida L. f.)

The objective of this work was to develop and characterize biodegradable starch films at 14 and 21 days of fermentation, aiming to develop packaging with added value. For the extraction of starch, yam tubers were washed, crushed, filtered and fermented for 14 and 21 days, and then filtered and dehydrated. Water-starch-glycerol mixtures were prepared in a randomized design using a factorial scheme (5x2), with five concentrations of glycerol (0, 0.5, 1.0, 1.5 and 2.0 mL) using two durations (14 and 21 days) and 6 replicates. The analyzed parameters were thickness, density, solubility, sorption kinetics, humidity, scanning electron microscopy characteristics and color. Analysis of variance revealed significant difference at the 1% level for the interaction of fermentation time and glycerol concentration for the studied variables. Overall, a 21 day fermentation period gave better characteristics of density, humidity and color and the addition of plasticizer positively influenced the parameters studied.   Key words: Gelatinization, packaging, fermentation, starch.