The enzymatic hydrolysis of lactose for ice cream mix

Since about 1914, the ice cream industry has been confronted with a texture defect known as lactose (milk sugar) crystallization. This defect is commonly called "sandiness" due to the sand-like feeling of the sugar crystals on the tongue. The demand for low fat-high solids-not-fat (ice milk) frozen dairy products has shown a marked increase during the past few years. High milk solids-not-fat improves the flavor, body, and texture of ice milk, therefore, due to these improvements some manufacturers tend to exceed the safe limit and "sandiness" developes. Ice milk is in danger of "sandiness" when more than 11% milk solids-not-fat is added to the mix because of the insolubility of the lactose.

There Is no adequate economical method by which a high milk solids-not-fat ice cream can be manufactured to negate the possibility of lactose crystallization. Recently the enzyme lactase which hydrolyzes lactose to simple and more soluble sugars, glucose and galactose, has become available for research and experimental employment. The enzyme lactase may be the answer to this ageing problem of "sandiness” in ice cream.

The objective of this study was to obtain a method for the quantitative determination of lactose In the presence of sucrose that could be used In an average ice cream plant for the purpose of measuring the enzymatic hydrolysis of lactose.