Milk, density

Interest in milk density is twofold. It has been used, along with the fat test, to estimate total solids contents. Raw milk is purchased by weight, but processed milk is sold by volume. 

Just as an increase in solids-not-fat increases milk density, so does the removal of water by processing. If there were no changes in physical state or chemical activity coefficients (e.g., hydration of proteins or insolubilization of salts), the density of the concentrated milk could be calculated from an equation derived by Jenness (1962) and presented in the second edition of this book. Data presented by Mojonnier and Troy (1922) conform to the equation but lack sufficient precision to indicate the small changes associated with some of the changes in physical state. 

There appears to be no effect of environmental conditions, stage of lactation, lactation number, or nutritional level of the animal on milk density, aside from the effects of these parameters on milk composition. 

Specific rotation is a physical property of a substance just as melting point boil mg point density and solubility are For example the lactic acid obtained from milk is exclusively a single enantiomer We cite its specific rotation m the form [a]o =+3 8° The temperature m degrees Celsius and the wavelength of light at which the measure ment was made are indicated as superscripts and subscripts respectively... 

Lactometers. These hydrometers are used in determining the density of milk. The various scales in common use are the following ... 

Various sources of lipid have been incorporated into ruminant diets to increase the energy density and provide the large amount of energy needed for slaughter animals to achieve market weight or for dairy cows to produce milk (see Milk and milkproducts). Fats also reduce the dustiness of feeds, increase the feedstuffs abiUty to pellet, and improve feed acceptabiUty. 

The methylene blue and resazurin reduction methods indirectly measure bacterial densities in milk and cream in terms of the time interval required, after starting incubation, for a dye—milk mixture to change color (methylene blue, from blue to white resazurin, from blue through purple and mauve to... 

In dye-binding tests, milk is mixed with excess acidic dye solution where the protein binds the dye in a constant ratio and forms a precipitate. After the dye—protein interaction takes place, the mixture is centrifuged and the optical density of the supernatant is determined. Utilization of the dye is thus measured and from it the protein content determined. Several methods for appHcation of dye-binding techniques to milk are given (24,25). 

Nutritional Value of Milk Products. Milk is considered one of the principal sources of nutrition for humans. Some people are intolerant to one or more components of milk so must avoid the product or consume a treated product. One example is intolerance to lactose in milk. Fluid milk is available in which the lactose has been treated to make it more digestible. The consumption of milk fat, either in fluid milk or in products derived from milk, has decreased markedly in the 1990s. Whole milk sales decreased 12% between 1985 and 1988, whereas the sales of low fat milk increased 165%, and skimmed milk sales increased 48% (35). Nutritionists have recommended that fat consumed provide no more than 30 calories, and that consumption of calories be reduced. Generally, a daily diet of 2000—3000 cal/d is needed depending on many variables, such as gender, type of work, age, body responses, exercise, etc. Further, there is concern about cholesterol [57-88-5] and density of fat consumed. Complete information on the nutritive value of milk and milk products is provided on product labels (36) (see also Table 4). 

Quicklime, CaO, has a density range of approximately 55 to 75 Ib/cu ft, and a molecular weight of 56.08. A slurry for feeding, called milk of lime, can be prepared with up to 45 percent solids. Lime is only slightly soluble, and both lime dust and slurries are caustic in nature. A saturated solution of lime has a pH of about 12.4. 

High density poly(ethylene) Bottles for milk and washing-up liquid ... 

SIRTOR] C R, BOSISIO R, PAZZUCCONI F, BONDIOLI A, GATTI E, LOVATI M R and MURPHY P (2002) Soy Milk with a High Glycitein Content Does Not Reduce Low-Density Lipoprotein Cholesterolemia in Type II Hypercholesterolemic Patients. Nutr Metab. 46 (2) 88-92. 

A good example of the many successftil DfE Partnerships is the Furniture Flame Retard-ancy Partnerhip. Pentabromodiphenylether (PentaBDE) was the primary flame retardant used in low density, flexible polyurethane furniture foam. Due to concerns over its use and the fact that the chemical was found widespread in the environment and in human tissue and breast milk, PentaBDE was voluntarily phased out of production by US manufacturers in January 2004. The industry needed alternatives in order to meet furniture flame retardancy requirements, but did not have the human and environmental health and safety information needed in order to compare the alternatives. DfE worked with the furniture manufacturers, foam manufacturers, and flame-retardant chemical suppliers along with governmental and environmental groups to evaluate possible alternatives. 

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