• Whey protein isolate polydispersity affects enzymatic hydrolosis outcomes

      O'Loughlin, Ian B.; Murray, Brian A.; Brodkorb, Andre; Fitzgerald, Richard J.; Robinson, A. A.; Holton, T. A.; Kelly, Tom A.; Teagasc Walsh Fellowship Programme; Enterprise Ireland; CC/2008/0001/A. (Elsevier, 24/05/2013)
      The effects of heat-induced denaturation of whey protein isolate (WPI) on the enzymatic breakdown of α-La, caseinomacropeptide (CMP), β-Lg A and β-Lg B were observed as hydrolysis proceeded to a 5% degree of hydrolysis (DH) in both unheated and heat-treated (80 °C, 10 min) WPI dispersions (100 g L−1). Hydrolysis of denatured WPI favoured the generation of higher levels of free essential amino acids; lysine, phenylalanine and arginine compared to the unheated substrate. LC–MS/MS identified 23 distinct peptides which were identified in the denatured WPI hydrolysate – the majority of which were derived from β-Lg. The mapping of the detected regions in α-La, β-Lg, and CMP enabled specific cleavage points to be associated with certain serine endo-protease activities. The outcomes of the study emphasise how a combined approach of substrate heat pre-treatment and enzymology may be used to influence proteolysis with attendant opportunities for targeting unique peptide production and amino acid release