title: Milk from cows of different β-casein genotypes as a source of β-casomorphin-7.
abstract: The aim of this study was to quantify β-casomorphin-7 in raw, hydrolyzed and processed milk in different stages of the cow lactation. The obtained results lead to the following conclusion: the highest amount of β-casomorphin-7 released from the hydrolyzed and processed milk is related to the β-casein A1 allele, irrespective of a lactation period. Some traces of β-casomorphin-7 in milk from cows with the β-casein A2 variant are probably a result of the acid hydrolysis of β-casein during its digestion with pepsin. It has been shown that processing of raw milk at high temperatures affects, in a slight degree, the differences between β-casomorphins-7 originating from different β-casein genotypes. The obtained results suggest a possibility to provide a new nutritional factor for milk quality based on the content of β-casomorphin-7 liberated in vivo from milk digested by a mixture of the gastrointestinal enzymes.
authors.affiliation: Department of Animal Genetics, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Cieślińska
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Kostyra
authors.forename: Henryk
authors.initials: H
authors.lastname: Kostyra
authors.forename: Kamil
authors.initials: K
authors.lastname: Oleński
authors.forename: Ewa
authors.initials: E
authors.lastname: Fiedorowicz
authors.forename: Stanisław
authors.initials: S
authors.lastname: Kamiński
mesh_terms: D000483:Alleles; D000818:Animals; D002364:Caseins / Q000235:genetics* / Q000378:metabolism; D002417:Cattle / Q000235:genetics; D004063:Digestion; D004723:Endorphins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D005511:Food Handling; D041981:Gastrointestinal Tract / Q000201:enzymology; D005838:Genotype; D006358:Hot Temperature; D006801:Humans; D006868:Hydrolysis; D007774:Lactation / Q000235:genetics* / Q000378:metabolism; D008892:Milk / Q000737:chemistry* / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: D002364:Caseins; D004723:Endorphins; D010446:Peptide Fragments; C041128:beta-casomorphin 7; D010434:Pepsin A