Milk reconstitution

In the case of concentrated UHT milks, physicochemical effects appear to predominate, although proteolysis also occurs, e.g. the propensity of UHT concentrated milk reconstituted from high-heat milk powder to age gelation is less than those from medium- or low-heat powders, although the formation of sediment is greatest in the concentrate prepared from the high-heat powder (see Harwalkar, 1992). 

Cultured buttermilk is manufactured by fermenting whole milk, reconstituted nonfat dry milk, partly skimmed milk, or skim milk with lactic acid bacteria. Most commercial cultured buttermilk is made from skim milk. Mixed strains of lactic streptococci are used to produce lactic acid and leuconostocs for development of the characteristic diacetyl flavor and aroma. Buttermilk is similar to skim milk in composition, except that it contains about 0.9% total acid expressed as lactic acid. The percentage of lactose normally found in skim milk is reduced in proportion to the percentage of lactic acid in the buttermilk. According to White (1978), the fat content of buttermilk usually varies from 1 to 1.8%, sometimes in the form of small flakes or granules to simulate churned buttermilk, the by-product of butter churning. Usually 0.1% salt is added. 

The participants were required to use at least one C internal standard for each isomeric group of congeners. The internal standards were added before starting the extraction procedure, to either the milk powder or to liquid milk reconstituted from the milk powder as appropriate. 

Clarification and homogenization precede evaporating and dryiag. Homogenization of whole milk at 63—74°C with pressures of 17—24 MPa (2500—3500 psi) is particularly desirable for reconstitution and the preservation of quaUty. 

Four reconstituted milks were prepared by blending hydrated skim milk powder (35g/L) with four different emulsions (35g/L) differing by composition of the fat-water interface. Whole reconstituted milks were coded MP (milk proteins), BCAS ( 6-casein), and BLG5 (j6-lactoglobulin 5 g/L). 

Skimming fresh whole milk allowed us to obtain milk fat globules with natural membranes that were blended at a concentration of 35 g/L with hydrated skim milk powder (35g/L). This reconstituted milk was coded CREAM. 

The pH of the reconstituted milks was adjusted to 6.4 with 1 N HCL. First, the acidification phase was carried out with glucono(5)lactone (2 g/L) at 30°C in order to exponentially decrease the pH and obtain a stabilized value corresponding to pH = 6.0 after 2 h incubation. Then, rennet was added to the acidified reconstituted milks at a final concentration of 19.5 mg/L and the coagulation phase was performed at 30°C for 3h. 

To reduce scattering effects and to allow a comparison between the different reconstituted milks, the data were normalized by reducing the area under each spectrum to a... 

TABLE 1 Average Diameter of the Natural Milk Fat Globules and Emulsified Milk Fat Droplets Stabilized by Different Fat-Water Interfaces in Reconstituted Milks... 

FIG. 5 Laurdan fluorescence excitation spectra recorded between 250 and 420 nm (emission wavelength, 439 nm) at different times during the acidification and the rennet-induced coagulation kinetics of BLG5 reconstituted milk 35, 70, 125, 175, and 300 min. A.U. = arbitrary units. 

FIG. 6 Evolution of the maximal fluorescence intensity of Laurdan at 363 nm (expressed in arbitrary units) recorded vs. time during BLG5 reconstituted milk acidification and coagulation phases (excitation 250-420 nm emission 439 nm). 

The principal component 1 (PCI) separated the acidification phases of BLG5, CREAM, BCAS, and MP clustered with negative values, from their rennet-induced coagulation phases that spread in a specific order associated with time from the left to the right of the map. These results showed that acidification and gelation of reconstituted milks induced different modifications in the fluorescence properties of Laurdan. 

Dynamic Rheological Properties of the Reconstituted Milks During the Coagulation Kinetics... 

The starting time for rheological measurements correspond to t = 120 min. Indeed, the rheological parameters were only recorded during the rennet-induced coagulation phase to avoid structural modifications during the acidification phase which may consequently influence the gelation process. Elastic and viscous properties of reconstituted milks... 

FIG. 10 Evolution of the elastic modulus (G ) recorded during the 3h of the rennet-induced coagulation phase of the reconstituted milks. 

TABLE 2 Rheological Parameters Measured for the Reconstituted Milks and Skim Milk During Coagulation Kinetics... 

Reconstituted milks with natural milk fat globules (CREAM) or emulsified milk fat droplets stabilized by jS-casein (BCAS), /i-lactoglobulin 5g/L (BLG5), skim milk proteins (MP). 

Originally, full cream milk solids were used but now where possible skim milk solids are substituted. A few products are still made from full cream milk solids but this is now rare. In some cases butter or butter oil is added to replace the fat that has been removed from the skim milk. In other cases the fat content of the milk is replaced with vegetable fat. It might appear curious that whole milk is effectively reconstituted from skim milk and butter but there are good reasons. Skim milk powder keeps better than full cream milk powder. Using skim milk and butter can under certain conditions be economically advantageous. 

While liquid milk is little used in biscuit manufacture for practical reasons to do with lack of stability, skimmed milk solids are used. The preferred ingredient is skimmed milk powder. This is normally dispersed in twice its own weight of water to ensure that it is evenly dispersed in the finished product. The reconstituted milk powder has the same keeping properties as liquid milk so it must be refrigerated. Merely dry blending the milk powder is likely to produce a finished product with small brown specks of caramelised milk powder in it. 

The certified reference material (CRM 450), used for the validation of the method, is real contaminated powdered milk with a certified content in PCB-52, PCB-101, PCB-118, PCB-156, and PCB-180. This material contains approximately 3.9% water and 25% fat. It is used after reconstituting and was supplied by the EC Community Bureau of Reference (BCR). 

Oral powder- The oral powder may be mixed with a small amount of water, milk, formula, soy formula, soy milk, or dietary supplement once mixed, the entire contents must be consumed in order to obtain the full dose. Acidic food or juice (eg, orange juice, apple juice, or apple sauce) are not recommended because of bitter taste. Do not reconstitute with water in its original container. Once mixed, store the oral powder for no more than 6 hours. May be refrigerated for up to 6 hours. 

Vyas, H. K., and Tong, P. S. (2004). Impact of source and level of calcium fortification on the heat stability of reconstituted skim milk powder. /. Dairy Sci. 87,1177-1180. 

The concentrations of fluoride in ready-to-feed formulas in the United States and Canada range from 0.1 to 0.3 mg/L while the fluoride concentrations of powdered or liquid-concentrate infant formulas depend mainly on the concentration of fluoride in the water used to reconstitute the product [8], A study on the concentration of fluoride in infant formula reconstituted with water in Australia revealed concentrations from 0.031 to 0.532 mg/L of fluoride for formulas reconstituted with water not containing fluoride, 0.131 to 0.632 mg/L of fluoride for formulas reconstituted with water containing 0.1 mg/L of fluoride and 1.031 to 1.532 mg/L if formulas were reconstituted with water containing 1.1 mg/L of fluoride [124]. Concentrations of fluoride in 10 samples of powdered milk formulas in Brazil ranged from 0.01 to 0.75 mg/L for those prepared with deionized water, from 0.02 to 1.37 mg/L for those prepared with bottled mineral water containing... 

Principal micelle characteristics. The structure of the casein micelles has attracted the attention of scientists for a considerable time. Knowledge of micelle structure is important because the stability and behaviour of the micelles are central to many dairy processing operations, e.g. cheese manufacture, stability of sterilized, sweetened-condensed and reconstituted milks and frozen products. Without knowledge of the structure and properties of the casein micelle, attempts to solve many technological problems faced by the dairy industry will be empirical and not generally applicable. From the academic viewpoint, the casein micelle presents an interesting and complex problem in protein quaternary structure. 

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