Effect of Glucono-Delta-Lactone (GDL) concentrations on physicochemical properties and rehydration kinetics of quick-cook oat rice

Quick-cook oat rice offers a promising alternative to traditional rice, aligning with current demand for nutritious, convenient grains. This study investigated the effects of glucono-delta-lactone (GDL) soaking (0–0.3%) on the physicochemical and rehydration properties of oat groats. GDL treatment increased water activity (from 0.516 to 0.623) and moisture content (8.7–9.6%). Texture analysis showed a progressive rise in hardness (3599 g to 4381 g), gumminess, and chewiness with GDL addition, indicating stronger structural rigidity. Rehydration ratio was highest at 0.1% GDL (1.75), comparable to the untreated control. Volume expansion was inversely related to GDL level, with the lowest observed at 0.1% GDL. Color analysis showed improved lightness and reduced browning. Peleg modelling revealed that GDL modified rehydration kinetics by lowering rate constants and increasing activation energy, peaking at 21.0 kJ/mol. These changes are attributed to the acid-induced tightening of the oat matrix, reducing water penetration while enhancing textural integrity. This study provides one of the first detailed assessments of GDL application in quick-cook oat rice and establishes 0.3% as an optimal concentration for balancing structural and rehydration performance. Findings support the potential of GDL as a clean-label acidulant in oat-based convenience foods, with implications for improving consumer appeal, shelf stability, and functional performance.