Hydrochloric acid‐modified high‐purity soybean insoluble dietary fiber from <i>Okara</i> attenuates NO ₂ ⁻ induced hepatic and renal injury in mice

Nitrite, a toxic substance, has been shown to adsorb and reduce organismal damage when natural adsorbents are used. Okara, due to its unique structure and adsorption properties, is one of the most eco-friendly and efficient adsorbents, naturally reducing nitrite-induced biotoxicity without side effects. Consequently, six groups of Kunming (KM) mice (n = 10) were comprehensively evaluated through tests for identifying physicochemical properties and physiological indexes. Additionally, the adsorption effects of high-purity soybean insoluble dietary fiber from Okara (HPSIDF) and hydrochloric acid-modified high-purity soybean insoluble dietary fiber from Okara (HCl-HPSIDF) on nitrite-induced toxicity were explored to ultimately determine their bioavailability potentials. Results indicated a 1.35-fold increase in water-holding capacity, a 1.32-fold increase in oil-holding capacity, and a 1.22-fold increase in water-swelling capacity. These physicochemical properties of HCl-HPSIDF were enhanced to improve the dietary fiber quality. Acid treatment increased HCl-HPSIDF's NO₂ ^-removal rate by 20.87% compared to HPSIDF and enhanced its adsorption capacity by 42.5%. The average particle size of HCl-HPSIDF was reduced by 32.82%, increasing NO₂ ^- contact with its adsorption sites and enhancing adsorption capacity. These improvements in changes in HCl-HPSIDF performance support its use as a natural, side-effect-free adsorbent for nitrite, with acid treatment enhancing dietary fiber functionality and enabling HCl-HPSIDF's application in adsorbents.