Hydrocolloid-mediated quality and starch digestibility of red rice gluten-free macaroni

This study aimed to develop functional gluten-free macaroni (GFM) from unpolished red jasmine rice flour ( Oryza sativa L. cv. Khao Hom Mali Gomain) and evaluate the effects of xanthan gum (XG) and guar gum (GG) on cooking quality, texture, bioactive compounds, and starch digestibility. GFM formulations were prepared with XG or GG at 0, 1.0, 1.5, and 2.0% (w/w flour basis), while wheat macaroni served as a reference. Hydrocolloid incorporation significantly improved cooking performance. Cooking loss decreased from 6.17% in the gum-free control to 3.20% in the formulation containing 2% XG, while cooking yield increased from 179.01% to 249.11% in the formulation containing 2% GG. The 1.5% GG formulation exhibited the highest measured hardness (2,345.91 g-force), whereas the 1.5% XG formulation exhibited the highest cohesiveness (0.35), gumminess (9.42 g-force), and chewiness (2.87 g-force). Compared with WM, GFM contained substantially higher levels of bioactive compounds, including total phenolics (98.42–113.47 mg GAE/100 g), anthocyanins (1.05–1.63 mg/100 g), and proanthocyanidins (45.42–67.42 mg CE/100 g), resulting in enhanced antioxidant activity. Among the gluten-free formulations, 2.0% XG exhibited the lowest cooking loss (3.20%) and estimated glycemic index (66.91), whereas 2.0% GG produced the highest numerical cooking yield (249.11%). Hydrocolloid effects were attribute-dependent, and no single formulation was established as optimal across all measured properties. These findings support the potential of unpolished red rice flour for developing gluten-free pasta, with hydrocolloid selection guided by the targeted technological and nutritional attributes.