Isolation and identification of antioxidant peptides from commercial soybean-based infant formulas

• Published in: Food chemistry 2014-04, Vol.148, p.147-154
• Main Authors: PUCHALSKA, Patrycja, MARINA, M. Luisa, GARCIA, M. Conceptión
• Format: Article
• Language: English
• Subjects: Antioxidants - chemistry; Antioxidants - isolation & purification; Biological and medical sciences; Food toxicology; Glycine max - chemistry; Hydrolysis; Infant Formula - chemistry; Infant Formula - economics; Medical sciences; Molecular Weight; Peptides - chemistry; Peptides - isolation & purification; Soybean Proteins - chemistry; Soybean Proteins - isolation & purification; Toxicology
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2013.10.030

Soybean-based infant formulas (SBIFs) based on soybean protein isolate (90% of proteins) are an interesting alternative to cow's milk infant formulas. Different works have demonstrated the presence of bioactive peptides in different soybean-based foodstuffs. The aim of this work was the evaluation, for the first time, of antioxidant peptides in five different commercially available SBIFs. Ultrafiltration through 10 kDa molecular weight cut-off filters was the most suitable extraction method. Despite peptide concentrations ranging between 1.19 and 2.27 mg/mL, similar antioxidant capacities were detected in all SBIF extracts. Extracts were further fractionated according to their molecular weight by ultrafiltration, and fractions from 5 to 10 kDa, 3 to 5 kDa, and below 3 kDa were obtained. The most active fraction was further fractionated by off-gel isoelectrofocusing and reversed-phase chromatography. Antioxidant fractions were also submitted to simulated gastrointestinal digestion (GI) with pepsin and pancreatin to evaluate their antioxidant capacity after digestion. Peptides were identified by HPLC-ESI-Q-ToF-MS/MS. At least 120 peptides were identified in every antioxidant fraction, with 42 peptides common to all SBIFs.