Yogurt is a production from fermentation of cow’s milk, and is one of major allergenic foods containing
a high allergenic protein, called b-lactoglobulin ( b-LG). Although allergenicity in yogurt is
not well known, patients with food allergy against cow’s milk generally eliminate it to prevent allergenic
syndromes. Because of strong relationship of allergenicity in food proteins with their antigenicity
as well as resistance to gastroentero-digestive enzymes, we used the methods of ELISA
inhibition, SDS-PAGE and immunoblots to assess antigenic level and peptic-digestibility against b-LG
in commercially available yogurt by comparison with two types of heat pasteurized cow’s milks (low
temperature long time-treated milk (LTLT) and ultra-high temperature-treated milk (UHT)). There
is less difference of antigenic activity against b-LG between yogurt and cow’s milks (LTLT and UHT).
In analysis of SDS-PAGE, the profile of peptic-digestion showed that intact protein of casein was rapidly
disappeared in cow’s milks (LTLT and UHT) and yogurt, whereas the digestibility of b-LG was
less in LTLT and well in UHT and yogurt. Similar profile of peptic-digestibility between UHT and
yogurt was revealed by immunoblot analysis with slight difference visualizing more fragmentized
small peptides along with antigenicity against b-LG in yogurt as compared with those in UHT.
These results are reasonable for patients with cow’s milk allergy to remove yogurt as same as cow’s
milk. In addition when the ill is gradually liberated, suitable release from avoidance food may be
present in order as former in UHT and yogurt and latter in LTLT, in the point of peptic-digestibility of b-LG.