Abstract
β-Lactoglobulin (β-LG) is a major allergen protein in cow's milk. The antigenic activity in soluble fractions of bread supplemented with dried skim milk was investigated by ELISA competitive inhibition and immunoblotting analyses using a rabbit anti β-LG. The bread added the dried skim milk dosage to be 0.1, 0.5 and 1 for the flour weight was prepared. Almost no antigenic activity of β-LG was detected in the salt solution extracts of bread with the addition of 0.5 skim milk dosage or less. β-LG was detected in 1% SDS containing 10% 2-mercaptoethanol (2-ME) extract from the bread but not with SDS only. It is suggested that the decrease in antigenic activity of β-LG was based on heat-induced polymerization through intermolecular disulfide bonds among β-LG and wheat proteins. The bread was hydrolyzed with pepsin until 180 min. β-LG was also not detected in the supernatant of pepsin digest of the bread supplemented with 0.5 dosage skim milk, whereas the precipitate of the pepsin digest included insoluble β-LG. Thus, no detectable level of antigenic activity of β-LG was recovered in the soluble fractions of the pepsin digest of the bread added skim milk.
