Heat–moisture treatment of rice grains affects starch digestibility and quality of low-gluten cookies made from blended wheat flour and treated rice flours

• 40% wheat flour was substituted by native or HMT rice flours varying amylose contents • Nutritional composition and pasting properties of the composite flours were changed • Composite flours exhibited higher water absorption capacity and lower swelling index • Cookies made from composite flours had better spread ratio and lower hardness • Cookie used HMT waxy rice flour had high resistant starch content and sensory quality Heat–moisture treatment (HMT) of both rice starch and flour significantly improved resistant starch content, depending on their amylose contents and treatment conditions. This study aimed to investigate proximate compositions and physicochemical properties of composite flours, prepared by replacing 40% of wheat flour with native or heat–moisture treated waxy, medium–grain, and long–grain rice flours, and evaluate physical properties, texture profile, in vitro digestibility, and sensory quality of low-gluten cookies made from blended flours. Partial substitution with native rice flours significantly decreased protein and lipid contents while increasing carbohydrate levels, and these compositional shifts were further accentuated by HMT. Composite flours also exhibited higher water absorption capacity and lower swelling index and pasting properties than those of wheat flour. Cookies prepared from blended wheat and rice flours had better spread ratio as compared to ones made solely from wheat flour. Texture profile analysis showed reductions in hardness, fracturability, springiness, and gumminess values when rice flour was added into cookies. The partial replacement with native or treated rice flours decreased amount of rapidly digestible starch, while increasing resistant starch content. Cookies containing heat–moisture treated waxy rice flour had the lowest concentration of rapidly digestible starch (54.11%) and the highest proportion of resistant starch (39.73%). Sensory quality confirmed acceptable quality across all recipes, with cookies containing native or treated long–grain rice flour rated most favorably. Overall, heat–moisture treated rice flour is a promising ingredient for formulation of wheat–based bakery products containing high resistant starch content.