title: Isolation and identification of antioxidant peptides from commercial soybean-based infant formulas.
abstract: 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.
authors.affiliation: Department of Analytical Chemistry, University of Alcalá, Ctra. Madrid-Barcelona Km. 33.600, 28871 Alcalá de Henares (Madrid), Spain. Electronic address: patrycia.puchalska@uah.es.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Puchalska
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Marina
authors.forename: M Concepción
authors.initials: MC
authors.lastname: García
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification; D006868:Hydrolysis; D041943:Infant Formula / Q000737:chemistry* / Q000191:economics; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D030262:Soybean Proteins / Q000737:chemistry* / Q000302:isolation & purification; D013025:Glycine max / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010455:Peptides; D030262:Soybean Proteins
keywords: Antioxidant capacity; Bioactive peptides; Food analysis; Q-TOF; Soybean based infant formula