Effect of starch physiology, gelatinization, and retrogradation on the attributes of rice starch-ι-carrageenan film

Edible films and coatings have been applied as the potential substitutes for conventional plastics in food packaging. However, their physical and mechanical properties still have limitations and thus require further improvement. In this study, we compared the physico–chemical properties of starches extracted from eight rice varieties and attempted to predict their promising effects on the physical (thickness and solubility), mechanical (tensile strength and elongation break), barrier (water vapor permeability), and optical properties (color and transparency) of rice starch-ι-carrageenan films. The results showed that starch amylose content and amylose–amylopectin associations during retrogradation play a significant role in determining various properties of the films. The film containing starch from “Reiziq” variety showed minimum thickness (0.08 mm), water vapor permeability (WVP) (2.7 gs⁻¹ m⁻¹ Pa⁻¹), solubility (43.12%) opacity (0.44%), and better mechanical properties, demonstrating the importance of selection of the source of the starch. The results also indicated that rice starch had compatibility with ι-carrageenan, and the blend of these two polysaccharides can be potentially used for coating fruit and vegetables.