Drying milk before

Edmondson et al (1971), who studied the enrichment of whole milk with iron, found that ferrous compounds normally caused a definite oxidized flavor when added before pasteurization. Aeration before addition of the iron reduced the off-flavor. The authors recommended the addition of ferric ammonium citrate followed by pasteurization at 81 °C. Kurtz et al. (1973) reported that iron salts can be added in amounts equivalent to 20 mg iron per liter of skim milk with no adverse flavor effects when iron-fortified dry milk is reconstituted to skim milk or used in the preparation of 2% milk. Hegenauer et al. (1979A) reported that emulsification of milk fat prior to fortification greatly reduced lipid peroxidation by all metal complexes. These researchers (Hegenauer et al. 1979B) concluded that chelated iron and copper should be added after homogenization but before pasteurization by a high-temperature-short-time process. 

Figure I. Effect of heating of soy milk before drying and effect of addition of N-ethylmaleimide (NEMI) to heated soy milk on the insolubilization of protein after drying. The curves are (a), dried without adding NEMI (b), dried after adding SEMI and (C), the values of (a) minus the values of (b). Curve (a) indicates total amount of insolubilized protein curve (b) indicates the amount of protein insolubilized by mechanisms other than by intermolecular disulfide bond formation and curve (c) indicates the amount of protein insolubilized through disulfide bond polymerization (3).

Processed milk products, which Include condensed, evaporated, malted and dry milks, cheese, whey, and ice cream and other frozen desserts, account for a large part of the overall Increase in zinc from the dairy products group. Cheese with its markedly increased use is chiefly responsible. Since 1909-13, the amount of zinc provided by cheese Increased more than fourfold and beginning in 1978, it has exceeded the amount contributed by fluid whole milk. In 1981, cheese provided 0.9 mg of zinc per capita per day or 7 percent of all the zinc in the food supply. Use of ice cream and other frozen desserts is now more than 10 times higher than in 1909-13. Half of this Increase occurred before the late 1930 s, and, since 1957-59, the small contribution of zinc from ice cream and other frozen desserts has been relatively stable. Other processed milk products have accounted for more zinc in recent years than at the beginning of the century. The amount, however, is somewhat less than the 0.6 mg per capita per day provided in 1946 when consumption of these products was highest. 

Various types of fermented milks, including yogurt, acidophilus milk, and cheese, generally contain less lactose than unfermented milk. The reduction upon fermentation has been reported to be from 20-50 percent. However, it should be noted that commercial yogurt contains more lactose than does milk because milk is fortified with dry milk solids before fer-... 

DeVilder and Bossuyt (12) determined water content in industrial skim milk and whole milk powders obtained by low, medium, and high thermal treatment of milk before spray drying. They also used two different technological processes for drying. They concluded that the accuracy of the method, even if very reliable, could be improved by calibrating for each factory or, preferably, for each production line. They determined... 

Dried buttermilk is made by either the dmm or spray process. Buttermilk is usually pasteurized before drying, even though the milk was previously pasteurized before churning. Dried buttermilk is used primarily for baking, confectionery, and dairy products. 

Administer at intervals of 8 hours. For optimal absorption, administer without food, but with water, 1 hour before or 2 hours after a meal or administer with other liquids such as skim milk, juice, coffee or tea, or with a light meal (eg, dry toast with jelly, juice, and coffee with skim milk and sugar or corn flakes, skim milk, and sugar). 

Before the extraction procedure may commence, the sample must be prepared in such a way that it is in a condition for extraction of the analyte(s). For analyzing sulfonamide residues in liquid samples such as milk, a pretreatment dilution step with water prior to direct fluorometric detection may be required (207). Dilution of milk with aqueous buffer (208) or sodium chloride solution (209) prior to sample cleanup has also been reported. For the analysis of honey a simple dissolution of the sample in water (210, 211) or aqueous buffer (212) is generally required. Semisolid samples such as muscle, kidney, and liver, require, however, more intensive sample pretreatment. The analyte(s) must be exposed to extracting solvents to ensure maximum extraction. The most popular approach for tissue break-up is through use of a mincing and/or homogenizing apparatus. Lyophilization (freeze-drying) of swine kidney has been carried out prior to supercritical-fluid extraction of trimethoprim residues (213). 

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