Development of a starch/gum-based edible coating for rice cakes to retard retrogradation during storage

A starch/gum blend as an edible coating solution for rice cakes was developed to retard starch retrogradation. It was prepared by blending waxy corn starch (WCS) with edible gums, such as gellan gum (GG) and sodium alginate (SA). The rice cakes were coated with starch/gum blends to preserve moisture and water holding capacity. After storing the rice cakes for 4 d at 25 degrees C and 45% relative humidity condition, moisture loss values from the uncoated and (1 g WCS + 1.25 g GG)/100 mL coated rice cakes were 3.36 +/- 1.51% and 1.08 +/- 1.08%, respectively. Hardness of the uncoated rice cakes (225.21 +/- 76.54 N) was significantly higher than that of the rice cakes coated with (1 g WCS + 1.25 g GG)/100 mL (144.45 +/- 48.97 N). Furthermore, the retrogradation rate (k) of the uncoated rice cakes (k = 0.452) exceeded that of the (1 g WCS + 1.25 g GG)/100 mL coated ones (k = 0.408) by 9.73%. Better sensory evaluation results were reported after (1 g WCS + 1.25 g GG)/100 mL blend coating than uncoated control. Taken together, newly developed edible coating with the (1 g WCS + 1.25 g GG)/100 mL blend was effective in retarding the retrogradation of the rice cakes and maintaining their texture.