A COMPARISON OF SOME CHEMICAL PROPERTIES OF YOGURTS MADE FROM CONTROL AND LACTASE‐TREATED MILKS

Abstract

ABSTRACT Certain properties of yogurts made from regular commercial skim milk and from milk which had been treated with lactase enzyme so that 70‐75% of the lactose was hydrolyzed to glucose and galactose were evaluated. Initially faster rates of acid production in lactase‐hydrolyzed milks (LH) during fermentation resulted in somewhat shortened processing times, although a decrease in the rate of acid production occurred earlier during fermentation in the LH milk so that final product pH was similar for both the control and LH yogurts. Control yogurts contained 5.0% lactose and 0.2% galactose while LH yogurts contained 1.6% glucose, 1.5% lactose and 2.1% galactose. Appreciably more lactic acid was produced in LH yogurts and this effect has been related to fermentation by the starter culture organisms of a greater proportion of the available sugar as glucose.