THE INFLUENCE OF LACTOSE HYDROLYSIS ON THE STRENGTH AND SENSORY CHARACTERISTICS OF VANILLA ICE CREAM
Lactose hydrolysis was investigated as a method of producing a more extrudable ice cream product. Ice cream 
mixes were treated with lactase from the microbial sources Kluyveromyces lactis and Aspergillus oryzae to produce 0% to 
100% lactose hydrolysis. Compression measurements and yield stress tests of frozen ice cream were both affected by the 
temperature of the samples. As the temperature decreased, the work required to compress the ice cream 10 mm (firmness) and 
the torsional shear stress both increased. There was a linear relationship between the firmness of lactose-hydrolyzed ice 
cream (0%, 80%, and 100%) and temperature (r2 = 0.98, 0.99, and 0.97, respectively). The treated samples were significantly 
softer than the control, but not different from each other. There was a significant difference (p < 0.05) in ice cream dippability 
between the control samples (0% hydrolyzed) and the treatment groups (80% and 100% hydrolyzed). The control group was 
consistently harder to dip. Hydrolysis of lactase in the ice cream mix produced a softer, more extrudable product.