Abstract
Kluyveromyces lactis β-Galactosidase was used to hydrolyze lactose in milk (28 and 56% hydrolysis) and in whey (26.25 and 52.5% hydrolysis). Hydrolyzed-lactose milk was used for the production of ice cream and stirred flavored yogurt while the hydrolyzed-lactose whey was used for the production of a soft drink (whey beverage). The added sucrose to these products was decreased to compensate the sweetness that gained as a result of lactose hydrolysis. The percentages of saved sucrose in ice cream were 6.53 and 13.06% for 28 and 56% hydrolyzed-lactose samples, respectively. Sensory evaluation of ice cream sweetness showed non-significant difference (p≤0.05) between the hydrolyzed-lactose samples (28 and 56% hydrolysis) and the untreated sample except for texture where a significant difference was observed between the 56% hydrolyzed-lactose ice cream and the control sample. The percentages of sucrose saving in stirred flavored yogurt were equal to 7.42 and 14.84% for 25.83 and 51.66% lactose hydrolysis, respectively, whereas in whey beverage they were equal to 3.25 and 6.5% for 26.25 and 52.5% lactose hydrolysis, respectively. Sweetness sensory evaluation of the stirred flavored yogurt and whey beverage showed non-significant differences among hydrolyzed-lactose samples and the untreated samples.
