Modification of Pearl Millet ( Pennisetum glaucum ) Starch: Cross‐Linking, Physicochemical and Toxicity Studies

ABSTRACT Starch, a key nutritional polysaccharide and industrial biomaterial, faces limitations in native form. Cross‐linking with glutaraldehyde significantly enhances the physicochemical properties and in vivo safety of pearl millet ( Pennisetum glaucum (L.) R. Br .) starch extends the functional applications. Native pearl millet starch (PNS) suffers from rapid digestibility and low thermal stability. This study modified PNS via glutaraldehyde cross‐linking (5% PGS1; 7.5% PGS2) to improve functionality and safety. Structural characterization confirmed covalent imine bond formation at 1643 cm − 1 as studied by Fourier transform infrared spectroscopy. The alteration in crystallinity of modified starch granules was disclosed by powder x‐ray diffractometry and the morphology of granules was also changed into porous structure as observed by scanning electron microscopy. The cross‐linking elevated the thermal stability (PGS1, Tg = 122.89°C, Δ H = 349.879 J/g) and water‐binding capacity while reduced the swelling power (PGS1 1.049% vs. PNS 1.875%) and amylose content (PGS2: 8.95% vs. PNS 19.69%). Acute toxicity and sub‐acute toxicity studied at 2000 mg/kg body weight in wistar rats demonstrated no mortality, behavioral changes, or histopathological abnormalities. The haematological/biochemical parameters remained unaltered during the study. The cross‐linked starch exhibits tailored digestibility, enhanced thermal resilience, and confirmed biosafety, positioning it as a sustainable biomaterial for controlled‐release pharmaceuticals and low‐glycaemic‐index foods.