TRANSMISSION ELECTRON-MICROSCOPY OF MILKFAT GLOBULES IN THE LOW-DENSITY LIPID FRACTION OF SWISS CHEESE WHEY

A low-density lipid fraction (LDLF) was recovered from Swiss cheese wh ey (SCW) residual lipids by highspeed centrifugation. The present stud y was conducted to determine the microstructural properties of the ext remely small-sized milkfat globules (MFG) in LDLF by: (i) freeze-fract ure transmission electron microscopy (FF-TEM) and (ii) thin-section TE M (TS-TEM). FF-TEM results revealed that MFG in LDLF were less than or equal to 1 mu m in size and were embedded in what appeared to be a sm ooth, protein-like matrix. The MFG in FF-TEM specimens exhibited eithe r planarly cleaved fractions with smooth cores or peripherally cleaved fractions with surface laminations. TS-TEM results revealed that the MFG in LDLF were dispersed in an aggregated nonlipid matrix.