Cake of brown, black and red rice: Influence of transglutaminase on technological properties, in vitro starch digestibility and phenolic compounds

This study aimed to evaluate the influence of transglutaminase addition on the technological properties and in vitro starch digestibility of gluten-free cakes of brown, black, and red rice, as well as the effect of baking on the content of phenolic compounds. Transglutaminase addition exerted significant effect in the technological properties only in the brown rice cake, resulting in a decrease in crumb firmness and an increase in the specific volume. Red rice cakes treated with transglutaminase presented a lower glucose release rate (k) compared to cakes without the enzyme. Cakes from pigmented rice varieties had lower crumb firmness and k values than brown rice cakes. Baking reduced only the contents of ferulic and p-coumaric acids and significantly increased the extractability of hydroxybenzoic, caffeic, caftaric, and protocatechuic acids. However, the addition of the enzyme resulted in a slight decrease in the total phenolic content of the cakes.