Development of a Cassava Starch-Based Foam Incorporated with Grape Stalks Using an Experimental Design

Concern about pollution caused by the incorrect disposal of plastic materials has led to an increasing interest in packaging made from natural resources and biodegradable materials. In this context, cassava starch-based foams incorporated with Cabernet Sauvignon grape stalks, one of the main residues from the wine industry, were prepared by thermal expansion, a simple and fast process. Grape stalks in small granulometries can provide a homogeneous matrix and help improve foam resistance. Glycerol, a by-product of the biodiesel production process, was added to improve the batter processability and the flexibility of the foams. Therefore, the influence of formulation parameters, such as the percentage of glycerol and grape stalks addition, and the particle size of the stalks was studied using a central composite experimental design. The desirability function of Statistica software was used to obtain a formulation that presented better properties for the foams. Results showed that the formulation with 13.6 wt% glycerol, 18.4 wt% grape stalks in the smallest particle size analyzed (Ø < 0.18 mm) was able to improve mechanical and humidity related properties and density of the foams. These results indicate that the foams developed in this study could be used as a substitute for EPS trays.