title: Composition, thermotropic properties, and oxidative stability of freeze-dried and spray-dried milk fat globule membrane isolated from cheese whey.
abstract: The milk fat globule membrane (MFGM) was isolated from cheese whey using a recently developed novel method. The cheese-derived MFGM contained about 17-19% lipids and 65-70% protein on a dry weight basis. About 50% of the lipids in MFGM were phospholipids. Compositional analysis of the cheese whey-derived MFGM showed that it is a rich source of phosphatidylserine, sphingomyelin, and bioactive proteins CD36, butyrophilin, xanthine oxidase, and mucin 1. Utilization of MFGM in foods as a source of nutraceutical lipids depends on its oxidative stability. In this context, the impact of drying methods, namely, freeze-drying versus spray-drying, on the storage stability of MFGM was studied. Freeze-dried (FD) and spray-dried (SD) MFGM samples were morphologically very different when examined by light microscope: The thermotropic phase transition temperature (T(m)) of lipids in the FD-MFGM was 37.8 °C, and it was 48 °C in SD-MFGM. This 10 °C difference in T(m) indicated that the drying method altered the thermodynamic state of phospholipids in MFGM. At all storage temperatures studied, the zero-order rate constant of lipid oxidation, as measured by hexanal production, was 1-2 orders of magnitude greater in the spray-dried than in the freeze-dried MFGM. The results clearly indicated that the choice of drying method affects morphological characteristics, the T(m) and oxidative stability of phospholipids in MFGM.
authors.affiliation: Department of Food Science, University of Wisconsin at Madison, Madison, Wisconsin 53706, United States.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhu
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Damodaran
mesh_terms: D002611:Cheese / Q000032:analysis*; D003890:Desiccation; D004355:Drug Stability; D005511:Food Handling / Q000379:methods*; D005612:Freeze Drying; D006017:Glycolipids / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry*; D066292:Lipid Droplets; D010084:Oxidation-Reduction; D044367:Phase Transition; D010743:Phospholipids / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics
chemical_list: D006017:Glycolipids; D006023:Glycoproteins; D010743:Phospholipids; C110367:milk fat globule