Abstract:

In the presence of glycerol, xanthan and hydroxypropyl carboxymethyl cellulose (HPCMC) were formulated for providing an enhancer for edible sweet potato starch films. To obtain optimal mechanical properties (tensile strength and tensile strain at break) and water vapor permeability, amounts of glycerol, xanthan and HPCMC were investigated by central composite design combined with response surface methodology. Results showed that better mechanical properties were obtained for sweet potato starch films prepared by adding 3.5－4.0 g of HPCMC, less than 2.0 g of glycerol and less than 2.0 g of xanthan to per 100 g of starch, and when the amounts of added HPCMC, glycerol and xanthan to per 100 g of starch were less than 2.0, more than 4.0 and less than 1.5 g, respectively, the water vapor permeability was lower. In practical production, selection of appropriate amounts of HPCMC, glycerol and xanthan should be done for optimal mechanical properties or water vapor permeability due to their different contributions to these perroperties.

Key words: food colloids, sweet potato starch films, response surface methodology, mechanical properties, water vapor permeability