Peptic hydrolysis of bovine beta-lactoglobulin under microwave treatment reduces its allergenicity in an ex vivo murine allergy model

In this study, the in vivo allergenicity of bovine beta-lactoglobulin (BLG) in peptic whey protein hydrolysates generated during microwave and conventional heating treatments was assessed. The allergenicity of the hydrolysates was explored by studying the reaction of the murine jejunum from previously immunised Balb/c mice to treated BLG in an Ussing chamber. Intestinal anaphylactic reactions after stimulation of the gut-associated immune system are a good indicator of potential in vivo allergenicity of whey hydrolysates. Fifty-two per cent of BLG was hydrolysed by pepsin after only 3min of microwave irradiation at 200 watts (W), yet it remained intact under conventional heating. Far- and near-UV circular dichroism spectra indicated significant changes in BLG secondary and tertiary structures with microwave irradiation at 200W. Pepsin whey protein hydrolysates obtained with microwave irradiation at 200W for 3min did not stimulate secretion of chloride in the Ussing chamber, as shown by the intensity of the short current values recorded (27.86Acm(-2)), compared to the conventional pepsin hydrolysates (68.21Acm(-2)). This demonstrates the low allergenicity of whey protein hydrolysates generated in this manner. These results confirm that microwave treatment combined with peptic hydrolysis could be applied to produce low allergenicity milk peptides.