The objective of the research study was to assess the possibility of using β-D-galactosidase in the production of milk ice cream with inulin and Bifidobacterium animalis ssp. lactis BB-12. The research included the determination of the acidity and chemical composition of mixes, the physical-chemical and sensory properties and the count of bacteria in milk ice cream during frozen storage. There were no statistically significant differences between the pH values of mixes with hydrolysed lactose and with traditional content of lactose. Nor were any differences found between the chemical compositions of those mixes, i.e. between the contents of protein, sugar and fat therein. Products are regarded as probiotic provided the count of bacterial cells therein is 6 log cfu·g-1 at a minimum. The ice cream mixes produced met this criterion and they even exceeded this minimum by about 3 log cfu·g-1. After the first day of storing ice cream, the pH was from 5.51 in low-lactose ice cream to 5.00 in ice cream with lactose. Extending the storage period from 1 to 28 days caused the pH value to increase by 0.04 units in ice cream with lactose and by 0.13 units in low-lactose ice cream. The enzymatic breakdown of lactose did not affect the increase in the number of Bifidobacterium animalis ssp. lactis BB-12 during fermentation of the mixes and during freezing and storing ice cream. Only in the case of low-lactose ice cream, extending the freezing storage time to 28 days resulted in a significant reduction in the count of Bifidobacterium animalis ssp. lactis BB-12. Only after the first day of storage, the lactose containing ice cream was characterised by a better fluffiness than the low-lactose ice cream. When producing the low-lactose ice cream, there should be considered their more sweet taste compared to the lactose containing ice cream. This suggests it could be possible to proportionally reduce the amount of sucrose to be added to low-lactose ice cream while obtaining a similar sweet taste as that of the ice cream with lactose.
probiotic ice cream, Bifidobacterium BB-12, inulin, lactase, β-D-galactosidase