Physicochemical properties of germinated and heat-moisture treated rice and quality of noodles substituted with treated rice

Pigmented rice is recognized for its high nutritional value but its application in noodle production is limited by poor texture and cooking quality associated with the bran layer. This study investigated the effects of germination, heat–moisture treatment (HMT), and their combination (GHMT) on the proximate composition, physicochemical properties of three unpolished pigmented rice having white-, red-, and purple-skin colors. The quality attributes of noodles supplemented with 30% of treated rice flours were also investigated. Germination significantly modified chemical composition by reducing lipid content, while enhancing water absorption capacity and swelling index due to enzymatic degradation of starch and protein matrices. However, noodles supplemented with germinated rice flour exhibited shorter cooking times but markedly higher cooking losses. In contrast, HMT and GHMT increased pasting temperature, reduced breakdown viscosity, and lowered swelling capacity, reflecting reinforced starch structures. These treatments resulted in longer cooking times and reduced cooking losses, indicating improved cooking stability. Textural profile analysis showed that hardness was significantly reduced by GHMT, while cohesiveness, adhesiveness, and springiness remained largely unaffected. In vitro digestibility analysis revealed that germination increased rapidly digestible starch, whereas HMT and GHMT significantly enhanced resistant starch contents to 32.4–42.7% and 27.8–55.6%, respectively. Sensory evaluation confirmed that noodles containing GHMT-treated flours achieved improved texture and flavor with acceptable overall acceptability. To sum up, pigmented rice flour subjected to GHMT represented a promising functional ingredient for producing nutritionally enhanced noodles with elevated resistant starch content and satisfactory sensory quality.