Everything about Lactose totally explained
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Lactose (also referred to as
milk sugar) is a
sugar which is found most notably in
milk. Lactose makes up around 2–8% of milk (by weight). The name comes from the
Latin word for milk, plus the -ose ending used to name sugars. Its systematic name is β-D-galactopyranosyl-(1↔4)β-D-glucopyranose.
Chemistry
Lactose is a
disaccharide that consists of β-D-
galactose and β-D-
glucose fragments bonded through a β1-4
glycosidic linkage.
Solubility
Lactose has a solubility of 1 in 4.63 measured %w/v. This translates to 0.216 g of lactose dissolving readily in 1 mL of water.
The solubility of lactose in water is 18.9049 g at 25°C, 25.1484 g at 40°C and 37.2149 g at 60°C per 100 g solution. Its solubility in
ethanol is 0.0111 g at 40°C and 0.0270 g at 60°C per 100 g solution.
Digestion of lactose
Infant
mammals are fed on milk by their mothers. To digest it an
enzyme called
lactase (β-D-galactosidase) is secreted by the intestinal
villi, and this enzyme cleaves the molecule into its two subunits
glucose and
galactose for absorption.
Since lactose occurs mostly in milk, in most mammals the production of lactase gradually decreases with maturity.
Many people with ancestry in
Europe, the
Middle East,
India, or parts of
East Africa, maintain normal lactase production into adulthood. In many of these cultures, mammals such as
cattle,
goats, and
sheep are milked for food. Hence, it was in these regions that genes for lifelong lactase production first
evolved. The genes of lactose tolerance has evolved independently in various ethnic groups.
Further Information
Get more info on 'Lactose'.
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