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 (r(2) = 0.98, 0.99, and 0.97, respectively). The treated samples were significantly softer that? 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.