High pressure processing impacts on the hydrolytic profile of milk coagulants

The hydrolysis of casein (CN) fractions induced by milk-clotting enzymes processed using high pressure processing (HPP) at previously optimized conditions (recombinant chymosin (212 MPa/5 min/10 °C), calf rennet (280 MPa/20 min/25 °C), bovine rennet (222 MPa/5 min/23 °C) and porcine pepsin (50 MPa/5 min/20 °C)) were studied. These enzymes were added to κ-casein (κ-CN) or to casein solutions and the degree of hydrolysis up to 60 min at 35 °C was evaluated using capillary electrophoresis. Compared to non-processed samples, the κ-CN (p < 0.05) had a faster hydrolysis, promoted by HPP processed recombinant chymosin (~12%) and calf rennet (~14%). In the casein solution, these enzymes and bovine rennet showed a caseinomacropeptide formation 12–18% faster than non-processed ones. Additionally, the hydrolysis profile of α and β-CN fractions were not altered by HPP and, as expected, the hydrolysis of these fractions were more rapid with bovine rennet and porcine pepsin. Thus, HPP may be useful to improve the specific activity of milk-clotting enzymes, without affecting their ability to hydrolyze other casein fractions31FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2012/13509-6; 2014/17782-