Microstructural and lipid composition changes in milk fat globules during milk powder manufacture

Abstract

The purpose of this study was to investigate the effects of milk powder processing conditions (pasteurisation, homogenisation and spray-drying) on the microstructure and composition of fat globules in cow milk. In general, the process of pasteurisation results in fewer changes in the microstructure and lipid composition than do other processing methods. The phospholipid, sterol, and the fatty acid composition of the phospholipids, with the exception of the fatty acids of total lipids, underwent significant changes under different processing conditions compared with the untreated milk fat globules. The contents and distribution of the phospholipids in pasteurised milk indicated a high level of stability, but the amounts of phosphatidylethanolamine, phosphatidylserine, and sphingomyelin were significantly affected by homogenisation. A reduction in the cholesterol content was observed after pasteurisation and homogenisation. The results indicate that processing had a significant effect on the composition and structure of the membrane of the phospholipids in milk fat globules.