Development and Characterization of Arrowroot Starch Films Incorporated with Grape Pomace Extract

Grape processing residues are a good source of bioactive and nutritional compounds. The incorporation of grape pomace extract (GPE) in starch films can be a strategy for the elaboration of new food packaging products for applications such as edible films or fruit strips. In this context, the objective of this research was to analyze the effect of incorporation and variation of concentration of GPE (0, 20, 30, and 40% mass/mass starch solids) on the physical chemical properties of arrowroot starch edible films created by casting. The GPE was characterized for moisture content, pH, total titratable acidity, total soluble solids, and anthocyanin content. Starch films with and without GPE were evaluated by analyzing their visual appearance, water activity, water content, thickness, water solubility, and water vapor permeability. The GPE had high water content, acidity, and anthocyanins content. The films with GPE showed a noticeable reddish color, similar to observed for the GPE. Increasing the concentration of GPE in the film resulted in significantly increased (p < 0.05) thickness (from 0.060 to 0.106 mm), water content (from 8.17 to 12.48%), solubility in water (from 13.33 to 33.32%), and water vapor permeability (from 3.72 to 6.65 g.mm/m2 day kPa). GPE increased the hydrophilic portion of the film, in addition to acting as a plasticizer, decreasing the molecular interactions of the polymer chain, and favoring its solubilization, which is desirable for applications such as edible films. The elaboration of arrowroot starch films with the incorporation of grape pomace is a good alternative for the reduction of by-products of grape processing.