Preparation of a potentially synbiotic dairy product fortified with galactooligosaccharides

We assessed the chemical, microbiological, rheological and sensory parameters of a fermented dairy product (FDP) containing a galactooligosaccharide (GOS) preparation. This was made from a solution of dried whey and skim milk containing 25% (w/w) lactose using a new enzyme with high transgalactosylation activity (Nurica: Danisco A/S). Conversion of the high initial lactose content enabled a good yield of 56% GOS to be achieved. The obtained GOS preparation was applied to the FDP with a probiotic culture of Bifidobacterium animalis ssp. lactis in amounts of 0, 2, 10, and 20% (w/w). The FDPs were stored and monitored for 9 weeks. Bifidobacteria showed counts higher than 10⁶ CFU/g throughout the storage period. GOS were not significantly utilized during fermentation and their changes during storage were also insignificant. Gel strength after fermentation showed a slight decrease with increasing doses of GOS preparation, but after 6 weeks of storage, the differences were no longer evident. The sensory analysis revealed the overall acceptability of the prepared FDPs, whilst the highest dose (20% GOS preparation) led to a sweeter taste.