Chinese name: lactose
English name: Lactose
CAS: 63-42-3
EINECS number: 200-559-2
Molecular formula: C12H22O11
MDL number: MFCD00151251
Molecular weight: 342.3
Appearance: white crystal or crystalline powder. It is sweet and has about 70% of the sweetness of sucrose. Odorless or slightly characteristic odor. Relative density d4201.525(water content). It is reductive and right-handed. There are two isomers, α-type and β-type.
α-lactose can be broken down into glucose and galactose by acid and lactase, and can be acted on by lactic acid bacteria to become lactic acid, but yeast cannot use it.
The crystalline precipitates in water as monohydrate C12 H22O11? H2O, if heated at 120 ° C, can become anhydrous. The melting point of anhydrous substance is 201 ~ 202℃, 1g can be dissolved in 5ml water or 2.6ml hot water, slightly soluble in ethanol, insoluble in ether.
β-lactose precipitates in hot water above 93 ° C, and the solubility is different from that of α-type, 1g is dissolved in 2.2ml water or 1.1ml hot water. Melting point 252℃, rotation [α]D20+53.6°. It can be hydrolyzed to glucose and galactose in 2% sulfuric acid emulsion.
Only exists in animal milk, human milk contains about 7%(5%-8%), milk contains about 4.5%(4%-5%). At body temperature, the mixture is balanced by a ratio of two parts alpha - and three parts beta -. Common lactose products are α-type.
Melting point: 222.8°C
Boiling point: 397.76°C (rough estimate)
Density: 1.5300
Refractive index: 1.5376 (estimate)
Storage conditions: 2-8°C
Solubility: Freely but slowly soluble in water, almost insoluble in ethanol (96%).
Acidity coefficient (pKa) : 12.39±0.20(Predicted)
Form: Powder
Color: White to off-white
Odor: wh. hard cryst. mass or wh. powd., odorless to sl. char. odor but readily absorbs odors, mildly swee
Water solubility: 5-10 g/100 mL at 20 ºC
BRN93796
Stability: Stable. Incompatible with strong oxidants.
LogP: -3.391 (est)
use
It is widely used in making baby food, candy, margarine, etc., and can also be used as culture medium, color layer absorbent and excipient
China
