Development of Biofoam Trays from Cassava Starch Blended with Citric Acid-modified Starch and Sugarcane Bagasse Cellulose Fiber

Abstract

Cassava starch, regarded as a major biopolymer of Thailand, has high potential as a raw material for producing biodegradable packaging. Cassava starch foam has undesirable properties for food packaging application including high water absorption as well as low strength and elasticity. This work developed and improved physical and mechanical properties as well as water resistance of cassava starch based foam trays by blending with 50% citric acid-modified starch and 0-15% sugarcane bagasse cellulose fiber by weight of starch. The higher viscosity of batter caused by the addition of citric acid-modified starch and cellulose fiber resulted in less expansion ability of starch foam and greater amount of batters required for baking foams. The foams containing 50% citric acid-modified starch or 5-10% sugarcane bagasse fiber by weight of starch exhibited significantly improved compressive strength (0.86 MPa and 0.47-0.74 MPa, respectively as compared to 0.27 MPa for native cassava starch foam) and modulus (1.95 MPa and 1.74-1.89 MPa, respectively as compared to 1.13 MPa for native cassava starch foam) but lesser water absorption capacity (2.54 g/g sample and 2.52-2.63 g/g sample, respectively as compared to 3.07 g/g sample from native cassava starch). The physical (i.e. density and color) and mechanical properties (i.e. compressive strength and modulus) of foam trays from cassava starch containing 50% citric acid-modified starch or 10% sugarcane bagasse fiber were comparable to commercial foam trays from cassava starch blended with fiber.