Germinated indica rice flour modified using five anionic polysaccharides: Analysis of physicochemical properties and multiscale structural characterization.

Although germination improves the nutritional and functional potential of indica rice, germinated indica rice flour is susceptible to retrogradation and structural instability. This study compared five food-grade anionic polysaccharides with different structural and functional profiles-namely, soybean hull polysaccharide (SHP), soluble soybean polysaccharide, κ-carrageenan (CG), low-methoxyl pectin, and gum arabic-to identify suitable modifiers for retrogradation inhibition and texture regulation in this flour. SHP yielded the lowest setback viscosity (228.33 vs. 358.67 mPa·s), thus providing the strongest short-term retrogradation inhibition. Meanwhile, CG produced the greatest hardness (218.09 g) and a more ordered, interconnected framework. Analyses of water mobility, short-range order, crystallinity, thermal behavior, and microstructure indicated that SHP promoted water redistribution and disrupted ordered starch packing, whereas CG reinforced gel network formation. Among the five polysaccharides, SHP and CG showed potential for retrogradation control and gel strengthening, respectively. These findings may guide polysaccharide selection for germinated indica rice flour-based products.