スキムミルク添加パンの調製時における β-ラクトグロブリンの不溶化：可溶性タンパク質画分における抗原性の低減化とペプシン消化による非再可溶化の検証

抄録

 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.