Fermented dairy beverages with addition of selected milk ingredients

The aim of the study was to produce the fermented dairy beverages from skimmed milk (SM) with addition of membrane separation products of milk, probiotic starter cultures (Bifidobacterium animalis ssp. lactis BB-12 and Lactobacillus acidophilus LA-5) and β-galactosidase enzyme. Twelve combinations of fermented dairy beverages were manufactured using skim milk (SM), microfiltration permeate (PMF), microfiltration retentate (RMF) with probiotic strains BB-12 or LA-5, with or without addition of β-galactosidase. The ceramic MF membranes with 0.1 μm pore diameter were used for separation. The number of Bifidobacterium was checked using TOS agar with selective supplement (MUP), while the number of Lactobacillus was determined using selective Rogosa agar. The following sampling plan was applied for microbial enumeration: after 24 hours of incubation at 37 °C, and after 168, 264, and 576 hours of storage at 6 °C. The beverages based on PMF and RMF enhanced the survival of probiotic bacteria during cold storage. The beverage RMF + β-galactosidase constituted the best environment in terms of probiotic bacteria survival. The initial number of Bifidobacterium was 8.17 log cfu mLE−1, which decreased to 7.95 log cfu mLE−1 after 24 days of storage. In case of Lactobacillus the number of microorganisms was 9.57 and 8.44 log cfu mLE−1, respectively. The beverage PMF without β-galactosidase supported growth of Bifidobacterium. An increase in the number of these microorganism was observed from initial number 7.42 to 8.65 log cfu mLE−1 after 24 days. The beverage based on SM and PMF with β-galactosidase did not support the growth of probiotic bacteria. The production of dairy beverages based on membrane separation products creates the possibilities for new product development with functional properties, comprising living probiotic cells, serum proteins, micellar proteins, mineral salts.