Anionic and zwitterionic phospholipids differently affect the heat coagulation of recombined concentrated milk emulsions

Heat-induced modifications were investigated upon heating recombined concentrated milk emulsions in the absence and presence of zwitterionic lysophospholipids or zwitterionic and anionic dialkylphospholipids of varying alkyl chain length. Among the lysophospholipids, 1-stearoyl-2-hydroxy-sn-3-phosphocholine demonstrated the greatest heat-stabilising effect, whereas 1-myristoyl-2-hydroxy-sn-glycero-3-phosphocholine resulted in increased viscosity and particle size as compared with its longer analogue. The protein recovery results showed that additional protein deposition at the oil-water interface was partly prevented upon lysophospholipids addition, especially by the ones characterised by a longer alkyl chain. The dialkylphospholipids exhibited a remarkable heat-stabilising effect upon addition at relatively low concentrations. As in the case of lysophospholipids, the longest alkyl chain phospholipids provided evidence of increased heat stability compared with 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol and 1,2-dimyristoyl-sn-glycero-3-phosphocholine. Moreover, anionic PG was characterised by an optimum concentration above which the heat-stabilising effect was weakened, whereas in the case of zwitterionic PC, the beneficial effect increased continuously with added concentration.