Characterization and stability of soybean meal peptide-zinc chelate prepared by solid state fermentation with Aspergillus oryzae

Abstract

This study aimed to prepare soybean meal peptide (SBMP)-Zn(II) chelate using solid state fermentation (SSF) with Aspergillus oryzae and characterize its structural properties. The SBMP showed good ability to chelate Zn(II). The Fraction 2–1 with the maximum chelating activity up to 365.75 mg/g was obtained from SBMP by chromatography. The identified 27 peptide segments in SBMP with 570–1500 Da (5–10 amino acids) mainly could combine with Zn(II) via the amino, carboxyl, hydroxyl and imidazole group to form peptide-Zn(II) chelates. The SBMP-Zn(II) chelate was stable in thermal processing, which was higher than SBMP due to the formation of eutectic structure in chelate. SEM analysis showed the formation of large polymer particles due to the crosslinking of Zn(II). The acid, thermal and high salt environment were the major factors affecting SBMP-Zn(II) dissociation. The chelate could effectively promote Zn(II) absorption in vitro simulated gastrointestinal digestion. These findings would provide the theoretical basis and technical support for the low-cost, efficient, and large production of the chelate and high-value resource utilization of SBM.