title: Application of Asian pumpkin (Cucurbita ficifolia) serine proteinase for production of biologically active peptides from casein.
abstract: The main objective of this study was to determine potential application of a serine proteinase derived from Asian pumpkin for obtaining biologically active peptides from casein. The course of casein hydrolysis by three doses of the enzyme (50, 150, 300 U/mg of protein) was monitored for 24 hours by the determinations of: hydrolysis degree DH (%), free amino group content (μmole Gly/g), RP HPLC peptide profiles and by polyacrylamide gel electrophoresis. In all hydrolyzates analyzed antioxidant activities were determined using three tests: the ability to reduce iron ions in FRAP test, the ability to scavenge free radicals in DPPH test, and Fe(2+) chelating activity. The antimicrobial activity of obtained peptide fractions was determined as the ability to inhibit the growth of Escherichia coli, Bacillus cereus and Pseudomonas fluorescens in a diffusion plate test. The deepest degradation, expressed as the DH [%] and the free amino group content (67% and 7528 µmole Gly/mg, respectively), was noted in samples hydrolyzed with 300 U/ml of enzyme for 24 hours, while in other samples the determined values were about three and two times lower. The results were in agreement with the peptide profiles obtained by RP HPLC. The highest antioxidative activities determined in all tests were seen for the casein hydrolysate obtained with 300 U/mg protein of serine proteinase after 24 h of reaction (2.15 µM Trolox/mg, 96.15 µg Fe(3+)/mg, 814.97 µg Fe(2+)/mg). Antimicrobial activity was presented in three preparations. In other samples no antimicrobial activity was detected.
authors.affiliation: Department of Animal Products Technology and Quality Management, Wrocław University of Environmental and Life Sciences, Wrocław, Poland. anna.dabrowska@up.wroc.pl
authors.forename: Anna
authors.initials: A
authors.lastname: Dąbrowska
authors.forename: Marek
authors.initials: M
authors.lastname: Szołtysik
authors.forename: Konrad
authors.initials: K
authors.lastname: Babij
authors.forename: Marta
authors.initials: M
authors.lastname: Pokora
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Zambrowicz
authors.forename: Józefa
authors.initials: J
authors.lastname: Chrzanowska
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D002364:Caseins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D028464:Cucurbita / Q000737:chemistry* / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D010455:Peptides / Q000378:metabolism; D057057:Serine Proteases / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D000975:Antioxidants; D002364:Caseins; D010455:Peptides; D057057:Serine Proteases