Question

What is the name of disaccharides sugar present in milk?

Answer 1

Hint: We have to remember that a sugar which is formed when two molecules of monosaccharides joined by glycosidic linkage is disaccharide. Similar to monosaccharides, disaccharides are water-soluble. Maltose, sucrose, and lactose are some of the common examples of disaccharides. We have to know that the disaccharides are of two types: reducing sugar, and non-sugar.

Complete step by step answer:
We must remember that a disaccharide that is present in milk is lactose. Lactose is a disaccharide. It is a sugar that contains subunits of galactose and glucose. The molecular formula of lactose is ${C_{12}}{H_{22}}{O_{11}}$ .Lactose is found around 2–8% of milk by mass.
We have to know that the lactose appears as a white, water-soluble, non-hygroscopic solid with a mildly sweet taste. It is used in the food industry.
Lactose is a disaccharide obtained from the condensation reaction of galactose and glucose that result in beta-1→4 glycosidic linkage. Its chemical name is beta-D-galactopyranosyl-(1→4)-D-glucose.
The hydrolysis of lactose is glucose and galactose, isomerized in basic solution to give lactulose, and hydrogenated catalytically to give the respective polyhydric alcohol, lactitol. It is a commercial product and is regularly used to treat constipation.
We have to know that milk products like milk yogurt and cheese has very little amount of lactose, lactase is employed as the bacteria used to make them eat lactose during the formation process.
Lactose contains relatively low carcinogenicity among sugars.

Note: In laboratorial process, we can detect lactose by Woehlk and Fearon’s test. Both these tests could be used to identify the various contents of lactose present in different dairy products like whole milk, lactose free milk, buttermilk, yoghurt, sour cream etc, coffee creamer, kefir etc.