Laser Light Scattering and Microscopic Properties of Milkfat Globules in Swiss Cheese Whey Low Density Lipid-containing Fraction

Abstract

Improved utilization of cheese whey, a by-product of cheese manufacture, is a major concern of the cheese industry. Large amounts of whey and whey products are used as nutritional and functional ingredients by the food and dairy industry. However, the residual lipids that remain in the whey interfere with the manufacture of whey protein concentrates by ultrafiltration processing and also adversely affect the functional properties and flavor stability of whey protein concentrate and other dried whey products. Information on the size and microstructure of residual whey lipid particles should allow the food industry to develop new and improved processing technologies to remove them from whey and utilize them as a novel food ingredient. Residual whey lipid from Swiss cheese whey has been fractionated by high speed centrifugation into: (a) low-density lipid-containing fraction (LDLF); (b) medium-density lipid-containing fraction (MDLF); and (c) high-density lipid-containing fraction (HDLF). Our objective for this study was to investigate the size and microstructural properties of the smallest-sized LDLF particles recovered from Swiss cheese whey by high-speed centrifugation using laser light scattering spectrophotometry (LLSS), light microscopy and scanning electron microscopy. LLSS results revealed that the size of LDLF particles ranged from < 0.1–about 4 μm with a predominance in the larger sizes. Light microscopy size results for LDLF particles agreed with LLSS results and also confirmed their globular microstructure. Electron micrographs further confirmed the size and provided more detailed information on the microstructural properties of LDLF particles.