Role of Differentiated-Size Milk Fat Globules on the Physical Functionality of Dairy-Fat Structured Products

Abstract

Bovine milk fat is one of the most important lipids in the human diet and originally exists as globules dispersed in the milk plasma. The typical size of milk fat globules (MFG) ranges from 0.1 to 15 μm with an average diameter of 4 μm (Walstra, 1995) as illustrated in Fig. 14.1a. The MFG size can be classified into three size fractions, i.e. small (<1 μm), intermediate (1-8 μm) and large (>8 μm) MFG sizes (Michalski, Briard, & Michel, 2001;Walstra & Oortwijn, 1969) with their volume-based percentages of 5%, 80% and 1-2%, respectively. The small size fraction accounts for 80% of the MFG size distribution on the basis of number of globules. Formation of various MFG sizes is governed by processes of assembly, growth and secretion of fat globules in the milk-secreting cells of the mammary gland of mammals (Timmen & Patton, 1988). Generally, MFG origins from the endoplasmic reticulum membranes where tiny intracellular lipid droplets (<0.5 μm) having a triacylglycerol (TAG) core enveloped by a single layer of proteins and polar lipids are generated. These lipid micro-droplets fuse to form bigger droplets, regarded as cytoplasmic lipid droplets, whose droplet-droplet fusion is regulated by specific calcium and protein complexes and fusion-promoting agents, e.g. gangliosides (Valivullah, Bevan, Peat, & Keenan, 1988). The intermediate size MFGs are progressively coated by the plasma membrane when being transported to the apical plasma membrane, resulting in the final tri-layer structure of intact milk fat globule membrane

A Monoblock Light-Scattering Milk Fat Percentage and Somatic Cell Count Sensor for Use in Milking Systems

“…Express analysis of the percentage of milk components (fat, proteins, lactose, amino acids, progesterone, etc. ), as well as microbiological impurities and somatic cells, provides the necessary information for assessing milk quality parameters, which enables farmers to establish a balanced feed for cows and diagnose their clinical condition [1][2][3]. The primary indicator of milk quality is the content of somatic cells, which is characterized by the somatic cell count (SCC), that is, the number of cells in a milliliter of milk.…”