Sugar Lactose Modification

Lactose, the major milk sugar, is also responsible for the osmotic regulation of lactation, thus causing the movement of water into milk. This carbohydrate is synthesized in the secretory vesicles of the mammary glands by the lactose synthase complex. As lactose cannot diffuse out of the vesicles, it draws water into the vesicles by osmosis. Thus, the volume of milk produced is directly dependent on the amount of lactose synthesized. 

One management tactic suggested for such patients is the avoidance of dairy products. However, as milk is a major component in the human diet, this deprives them from the use of a valuable nutritional source. In addition, since milk can provide much of the required calcium for maintaining bone health, lactose intolerance can also be associated with osteo-paenia in old people (Corazza et al., 1995). A report suggests that by 2020, half of all American citizens older than 50 will have low bone mass and be at risk for fractures from osteoporosis if appropriate dietary and other precautions are not followed (Carmona, 2006). Therefore, excluding milk from diet has adverse effects on health. 

An alternative to produce low-lactose milk is overexpression of jS-galactosidase in milk. However, the monosachharides produced within the formed milk increases the osmotic pressure within the alveolar lumen, thereby drawing more water and resulting in further dilution of other milk components (Bremel et al., 1989). 

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Several solid polyols can be used as direct compression diluents, usually after some physical modification. Most such polyols can be obtained from natural sources, but are usually manufactured by hydrogenation of the parent sugar molecule. Some properties of polyols, together with comparative data for lactose and sucrose, are shown in Table 6. 

Preparation. The method most frequently used involves the hydrolysis of lactose by acids, and fractional crystallization of the D-galactose liberated. A modification of the method entails removal of the D-glucose by fermentation with yeasts, and crystallization of the D-galactose remaining. Water-soluble gums extractable from the western or eastern larch also serve as sources of the sugar.88... 

Differential scanning calorimetry experiments revealed the presence of at least four types of lactose besides the known a- and 3-modifications, some of which are dehydrated forms. Attempts have been made to identify the rate-determining step in the dehydration of fructose to S-(hydroxymethyl)furfural by measuring kinetic isotope effects." A spin-probe EPR study at elevated temperatures of some sugars in connection with the desiccation tolerance of biologiGal materials indicated that trehalose and sucrose-raffinose mixtures are distinguished by stability of thdr phase state and their low effective activation energy for rotational molecular motions. ... 

The isolation of crystalline isomers of the sugars provided additional evidence for the inadequacy of the aldehyde formulas. As early as 1856, two crystalline modifications of lactose were prepared by Erdmann 19), the forms which are now designated a- and iS-lactose he discovered their mutarotations to the common equilibrium rotation. Tanret 20) in 1895 reported the isolation of three forms of glucose which he described as a-,... 

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