The Role and Properties of Lactose in Milk and Dairy Products

Lactose, commonly referred to as milk sugar, is the primary carbohydrate found in milk. As a disaccharide, lactose consists of two monosaccharides: glucose and galactose. This milk sugar is found in a true solution within milk, making it easily accessible for various biochemical processes. Besides lactose, milk also contains trace amounts of other sugars like glucose, galactose, and oligosaccharides.

Lactose plays a crucial role in dairy products due to its ability to be fermented by lactic acid bacteria, which convert it into lactic acid. This fermentation process is essential for the production of yogurt, cheese, and other fermented dairy products, as it influences texture, flavor, and preservation.

Lactose exists in two isomeric forms: α-lactose and β-lactose. The β-lactose form is more soluble in water than the α-lactose form, affecting the solubility and crystallization of lactose in dairy products. In cow's milk, lactose makes up approximately 4.9% of the milk's composition. Interestingly, the lactose content of milk is inversely related to its ash content, meaning higher ash content correlates with lower lactose levels.

Furthermore, udder infections can significantly impact milk composition. Such infections often lead to increased chloride levels in milk and a reduction in lactose secretion, highlighting the sensitivity of lactose production to the cow's health. Understanding these dynamics is crucial for dairy production and quality control.
The Role and Properties of Lactose in Milk and Dairy Products