Interfacial properties and transmission electron microscopy revealing damage to the milk fat globule system after pulsed electric field treatment

Abstract

Changes to the bovine milk fat globule membrane (MFGM) were assessed after a combination of pre-heating at 55 °C for 24 s followed by pulsed electric field (PEF) treatment at 20 kV cm−1 or 26 kV cm−1 for 34 μs, and compared to changes after thermal treatments at 63 °C or 73 °C. A decrease in milk fat globule size, increase in ζ-potential and specific surface area, and adsorption of plasma proteins onto the surface of the MFGM occurred after pre-heating and PEF and thermal treatments. The increase in ζ-potential was correlated with the surface coverage of MFGM with the plasma proteins which was further confirmed by transmission electron microscopy. PEF treatment of whole milk had less impact on the structure of milk fat compared to high temperature thermal treatments alone. This study suggests that a combination of PEF and low heat treatment at 55 °C may have less detrimental effect on the fat globule surface in whole milk.