Constrained Mixture Design to Optimize Formulation and Performance of Foams Based on Cassava Starch and Peanut Skin
Foams composed of cassava starch, peanut skin, and glycerol were developed by thermal expansion process. A constrained mixture design was applied to evaluate the effect of components on flexural mechanical properties and water absorption capacity (WAC). The interaction between cassava starch and peanut skin exhibited a significant antagonistic effect in WAC. Effects of the concentration of cassava starch, glycerol and the interactions between cassava starch–glycerol and peanut skin–glycerol were significant to mechanical properties. Desirability function was applied to optimize the formulation in order to obtain less hydrophilic, more flexible and more resistant foams. Optimized formulation consisted of 23.71% (w/w) peanut skin and 12.68% (w/w) glycerol, based on solids content (cassava starch + peanut skin). Optimized foam showed experimental values similar to those predicted, validating the fitted models for defined constraints. This foam showed an important improvement in hydrophilicity indicated by a decrease in WAC, compared to cassava starch-based foams without peanut skin.
KeywordsDesirability function Starch foams Flexural mechanical properties Hydrophilicity
The authors thank the Laboratory of Analysis of Physical Properties of Food (LAPFA) and Chemical Engineering Department from Federal University of Rio Grande do Sul (UFRGS) by technical support and to CAPES-Brazil for financial support.
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