Disruption and reassociation of casein micelles under high pressure

摘要

High pressure (HP) treatment affects many constituents of milk (for reviews see Huppertz et al. 2002; Needs, 2002); particular in the properties of casein micelles in HP-treated milk differ considerably from their counterparts in untreated milk. In milk treated at 100-200 MPa, average casein micelle size differs little from that of untreated milk (Needs et al. 2000a; Huppertz et al. 2004a; Regnault et al. 2004; Anema et al. 2005), but micelle size in milk treated at 250 MPa for ≥ 15 min is considerably higher than in untreated milk, probably due to HP-induced aggregation of casein micelles (Huppertz et al. 2004a, b; Regnault et al. 2004); after treatment at 300-800 MPa, micelle size is ～ 50% lower than that in untreated milk (Needs et al. 2000a; Huppertz et al. 2004a, b; Anema et al. 2005). HP-induced changes in average casein micelle size are irreversible on subsequent storage, except for the increase in micelle size after treatment at 250 MPa (Huppertz et al. 2004a).