Effect of Food-Derived Hydrocolloids on Nutritional, Antinutritional, Glycemic, and Structural Characteristics of Millet-Based Rice Analogue

Abstract

The present study investigated the effect of food-derived hydrocolloids on the nutritional, antinutritional, glycemic, and structural properties of a millet-based rice analogue (MBRA). Pectin and psyllium husk were incorporated individually and in combination (0.5-3%, w/w) into a composite flour blend of pearl millet, sorghum, and parboiled rice, followed by hot extrusion processing. The inclusion of hydrocolloids significantly enhanced total phenolic content, antioxidant activity, and textural attributes of MBRA (p ≤ 0.05). Optimal results were obtained at 1.5% pectin and 1.5% psyllium husk, yielding improved nutritional composition with total starch (66.05%), antioxidant activity (312.20 μg/g), total phenols (36.80 mg/100 g), and a moderate glycemic index (51.67), along with enhanced mineral content. Rheological analysis revealed an increase in storage modulus (G′), indicating the formation of a more elastic and interconnected matrix due to interactions among hydrocolloids, starch, and proteins. Fourier Transform Infrared spectroscopy showed shifts in the fingerprint region (900-1200 cm⁻1), suggesting enhanced molecular interactions and reduced crystallinity. Thermal analysis demonstrated increased gelatinization temperatures and decreased enthalpy, indicating improved thermal stability. Pasting properties exhibited higher peak and final viscosities, reflecting improved water-holding capacity, while reduced holding strength indicated lower resistance to thermal stress. Textural analysis showed decreased gumminess and chewiness, resulting in a softer and more palatable product. Scanning Electron Microscopy confirmed a denser and more uniform microstructure with reduced porosity. Overall, the study highlights the potential of hydrocolloids as functional ingredients to enhance the quality and acceptability of millet-based rice analogues.