Digestibility and antigenicity of β-lactoglobulin as affected by heat, pH and applied shear

Processing induced conformational changes can modulate digestibility of food allergens and thereby their antigenicity. Effect of different pH (3, 5, 7), temperature (room temperature, 120 degrees C) and shear (0 s(-1), 1000 s(-1)) on simulated gastrointestinal digestibility of beta-lg and post digestion antigenic characteristics have been studied. At all pH levels unheated beta-lg showed resistance to peptic digestion with high antigenic value while it was fairly susceptible to pancreatin with moderate reduction in antigenicity. Heating at 120 degrees C significantly improved both peptic and pancreatic digestion attributed to structural alterations that resulted in much lower antigenicity; the level of reduction being pH dependant. The lowest antigenicity was recorded at pH 5. Shearing (1000 s(-1)) had a minor impact reducing digestibility and thereby enhancing antigenicity of unheated beta-lg at pH 5 and 7 slightly; however in conjunction with heating (120 degrees C) it reduced antigenicity further irrespective of the pH. Overall, treatment at pH 5, 120 degrees C and 1000 s(-1) could potentially reduce post digestion antigenicity of beta-lg. (C) 2016 Published by Elsevier Ltd.