ABSTRACT
An excess of lactose is produced in the North American dairy industry as a by-product of cheese manufacture in the form of whey or whey permeate. These by-products are a potential source of food for both human and animal consumption, plus there are technologies for whey utilization that are being investigated. One of these investigated methods is to convert the D-galactose in the disaccharide lactose in whey or whey permeate into the low-calorie sweetener D-tagatose via isomerization. Functional uses of D-tagatose as food additives are as a sweetener, texturizer, stabilizer, humectant, formulation aid, and to provide several health benefits to consumers such as attenuating a glycemic response and preventing tooth decay. Two processes for manufacturing D-tagatose can be summarized: chemical isomerization method and enzymatic method. L-arabinose isomerase mainly catalyzes the isomerization of the pentose-sugar L-arabinose to the keto sugar L-ribulose. D-tagatose has the potential for use as a low-calorie oral prescription drug additive to mask unpleasant taste.
