title: Isolation and characterization of three novel peptides from casein hydrolysates that stimulate the growth of mixed cultures of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus.
abstract: In this study, sodium caseinate hydrolysates produced by papain with strong growth-stimulating activity for Streptococcus thermophilus (St) and Lactobacillus delbrueckii subsp. bulgaricus (Lb) were obtained. A series of separation methods including ultrafiltration, macroporous adsorption resin chromatography, gel filtration chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC) were applied to isolate and purify the peptide(s), which were mainly responsible for the activity. Finally, three novel growth-stimulating peptides, H-2-A, F2-c, and F2-b, corresponding to amino acid residues 29-35 and 103-108 of bovine α(S2)-casein and 181-186 of bovine α(S1)-casein, respectively, were obtained. With supplementation of H-2-A, F2-b, or F2-c at a protein concentration of 0.3%, the biomass yield of these two lactic acid bacteria (LAB) was enhanced by 193.3, 166.7, or 151.7%, respectively. In addition, there were significant (p < 0.05) increases in viable counts of St and lactic acid production of LAB in the presence of the purified peptides.
authors.affiliation: South China University of Technology, Guangzhou 510640, China.
authors.forename: Qingli
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jiaoyan
authors.initials: J
authors.lastname: Ren
authors.forename: Mouming
authors.initials: M
authors.lastname: Zhao
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhao
authors.forename: Joe M
authors.initials: JM
authors.lastname: Regenstein
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Jiana
authors.initials: J
authors.lastname: Wu
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D048668:Lactobacillus delbrueckii / Q000187:drug effects / Q000254:growth & development*; D010206:Papain / Q000378:metabolism; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D010455:Peptides / Q000302:isolation & purification* / Q000494:pharmacology*; D048249:Streptococcus thermophilus / Q000187:drug effects / Q000254:growth & development*
chemical_list: D000596:Amino Acids; D002364:Caseins; D010446:Peptide Fragments; D010455:Peptides; C475729:casein hydrolysate; D010206:Papain