In vitro hydrolysis by pancreatic elastases I and II reduces beta-lactoglobulin antigenicity

Bovine whey proteins such as alpha-lactalbumin and beta-lactoglobulin are with bovine caseins the most commonly used proteins in infant formulas owing to their high nutritional value. However, these cow milk components are not always well tolerated and can induce allergies in infants. The purpose of this study was therefore to investigate the gastric (pepsin) and pancreatic (trypsin, chymotrypsin and elastases I and II) enzymatic hydrolysis of beta-lactoglobulin with the aim of finding a means to reduce its antigenicity. Elastases I and II were first purified from porcine pancreatic acetone powder. After differential precipitation steps, elastases I and II were separated by cation-exchange chromatography. The conditions regarding beta-lactoglobulin hydrolysis by gastric and/or pancreatic enzymes were similar to those used for hypoallergenic milk preparations. Elastase II and to a lesser extent elastase I, were effective in enhancing beta-lactoglobulin hydrolysis via a mix of pepsin, trypsin and chymotrypsin and in reducing the residual antigenicity of hydrolytic products. The same hydrolytic percentage was observed when elastase I or II were added, while the residual antigenicity was lower in the presence of elastase II than in the presence of elastase I. The introduction of elastases in the pancreatic mix can therefore be proposed to enhance the hydrolysis of cow milk components in hypoallergenic milk preparations.