Preparation and structural characterization of peanut peptide–zinc chelate

Abstract

Peanut protein isolate was hydrolyzed by trypsin. The resulting peanut peptide fractions (PPF) were then divided into three molecular weight components by ultrafiltration (PPF1, MW >5 kDa; PPF2, 3 kDa < MW <5 kDa; PPF3, MW <3 kDa; and untreated PPF). Experiments showed that PPF3 had the best capacity for chelation with zinc. PPF3 and the PPF3–Zn chelate were characterized by Ultraviolet spectrophotometry, Fourier-transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, Energy disperse spectroscopy, Fluorescence spectroscopy, and Thermogravimetric analysis. The results showed that the apparent characteristics and internal structures of PPF3 were changed by chelation of Zn2+. PPF3 contained sufficient metal-binding sites, with – COOH, – OH, and – NH2 potentially participating in coordination with Zn2+ to form the PPF3-Zn chelate. Furthermore, the results suggested that peanut peptides might chelate with zinc to act as an emerging carrier for zinc supplements.

Keywords

• peanut peptide
• peptide–zinc chelation
• characterization
• zinc supplement