Sugar milk: Lactose

Disaccharides are too large to move through cell membranes, so they must be digested via hydrolysis. Disaccharides found in food include sucrose, lactose, and maltose, a grain sugar, all of these contain glucose.

Lactose is a naturally occurring carbohydrate found in the milk of most mammals. The disaccharide lactose occurs in milk, mainly free with a small extent as a component of higher oligosaccharides. Its concentration in milk varies with the mammalian source from 2.0% to 8.5%. Cow and goat milks contain 4.5–4.8% and human milk about 7%. It is the primary carbohydrate for developing mammals.

Lactose production in nature is limited to the mammalian breast, which contains the enzyme system (lactose synthase) necessary to create this linkage.

Lactose is a disaccharide consisting of galactose and glucose, linked by a β -L-4 glycosidic bond.  In milk, lactose is normally found as either α-lactose or β -lactose or amorphous glass form (mixture of α- and β -forms).

Lactose is one of the lowest ranking in terms of sweetness, being about one-sixth as sweet as sucrose.
Sugar milk: Lactose

Sweetened condensed milk

Sweetened condensed milks is an evaporated milk product containing added sugar. The milk intended for the retail market are packed in cans.

In canning sweetened condensed milk, care is taken to avoid condensation on the product surface which might raise the water activity (Aw) sufficiently to support yeast and mould growth in the event of contamination.

This product is not sterilized but is preserved by the high concentration of sugar which raises the osmotic pressure of the product to a level where it is microbiologically stable. The equipment is similar to that used for evaporated milk, except that sugar is added in a hot well before condensing (evaporating) the liquid.

After sugar addition, the milk is subjected to a heat treatment which not only acts as a pasteurization step but also inactivates most of the enzymes which might give rise to spoilage.

According to standards, sweetened condensed milk must contain a minimum of 8.5% fat and 28% total milk solids, including fat (fat to solids-not-fat ratio = 1:2:3). The final product contains 43-45% sugar.

The sugar confectionery industry is a major user, for the production of toffee, caramel and fudge. Toffees made from sweetened condensed milk are normally smoother than those made from milk powder: presumably the milk protein in sweetened condensed milk is in a less damaged form than in milk powder.

The low moisture content of sweetened condensed milk allows a reduction in boiling time and the possibility of hydrolysis of sucrose to fructose and glucose is avoided.
Sweetened condensed milk

Sugar and Vitamins in Milk

Sugar
Lactose is the characteristics carbohydrate of milk, is a disaccharides with the formula
C12H22O11.H2O

The chemical reaction of sugar brown shows that it does not exist in the form of a chain but has a ring structure. With glucose and galactose, the ring forms from the C1 atom to the C5 atom via an oxygen bridge. Bonding takes place between the C4 atom of glucose and C1 atom galactose. The position of the OH group on the C1 atom is in the function of direction (alpha-position for the right and Beta-position for the left direction).

Lactose has technological importance during all acidification process involving milk (acidified products, creaming ripening), in which it serves as the substrate for the lactobacillus bacteria, as well as during its direct manufacture. In addition, lactose can participate in reactions during technological process, leading to the formation of lactulose and in Maillard reactions.

Vitamin
Vitamins are formed in plants through the influence of sunlight. They are essential reagents for men and animal for maintaining and growth of cell substances as well as to guarantee the normal functioning of the organs. They function with the minutest amounts and do not provide energy.
Vitamins are transferred onto the body via food or are made out of provitamins, if the level of vitamins contained in food is too low, then deficiencies (hypo and avitaminosis) can occur, which may result in death. In a few cases, the intake of too high levels of vitamins, e.g., through supplements can lead to disturbances (e.g., hypervitaminosis).

Milk contains all the essential vitamins, but in varying and sometimes insufficient amount. The vitamin content of raw milk is influenced mainly by the feeding and health of the animal. The vitamin content can be reduced further by treatment. Milk also contains the fat soluble vitamins E (tocopherol), F and K as well as the water soluble vitamins B1 (thiamin), B12, vitamin H, pantothenic acid, folic acid and nicotinic acid amide.
Sugar and Vitamins in Milk

Lactose (milk sugar)

Lactose (milk sugar)
The characteristics carbohydrate of milk is lactose, a disaccharides composed of one molecule of D-glucose and one of D-galactose, which is synthesized in the mammary gland.

The lactose content of cow’s milk is fairly constant, ranging from 4 to 5%. In contrast, milk from cows with mastitis have lactose contents as low as 2.7%.

The more lactose a milk contains, the sweeter its taste. Cow’s milk, with a mean lactose content of 4.6%, tastes faintly sweet.

It is interesting to note that although sweet (nonacid), whey has about the same concentration of lactose as the milk from which it is made, it is much sweeter than milk, due to undoubtedly to the removal of casein.

Lactose in milk is readily fermented by a number of bacteria to yield lactic acid. The changes that accompany the conversion of lactose into lactic acid is associated with the souring of milk. The odor of sour milk is not due to lactic acid but to other volatile products formed during fermentation.

Lactose, in common with other disaccharides, must be hydrolyzed by specific enzymes in the digestive tract into monosaccharide before absorption and utilization by the body.

Lactase the enzyme responsible for the hydrolysis of lactose to D-glucose and D-galactose occurs in the intestinal mucosa of mammals. When lactose intake exceeds the amount that lactose can hydrolyze, symptoms of lactose intolerance (flatulence, cramps, and diarrhea) may ensue.
Lactose (milk sugar)