Effect of protein and carbohydrate components upon quality parameters and viable probiotic bacteria content in milk mixtures during their drying and storage

Abstract

Results of studies of dry milk based mixtures for extremal nutrition, obtained by spray drying at various temperatures are presented. Viable cells number, sensorial, physical and chemical parameters are determined. The increase of dry whey protein concentrate (WPC) content from 1% to 6% leads to an increase in the protein content in the product from 25% to 37%. At the same time, the relative rate of dissolution increases by 2.7 times, and the active acidity decreases by 0.16 pH units. It is established that the drying temperature of the mixtures is 130 ± 2 °C at the inlet of the drying tower and 60 ± 2 °C at the outlet, can be is recommended for maximum preservation of the viability of probiotic microorganisms. Streptococcus thermophilus strain turned out to be the most resistant to elevated drying temperatures in comparison with other strains. It is noted that the introduction of WPC effected the survival of probiotic bacteria to survival during drying and storage positively. The smallest losses of viable microorganisms after drying the product were found in test samples with strains of Streptococcus thermophilus and Enterococcus faecium and addition of WPC to the product formulation, while the number of viable cells decreased by 1.7 times and 2.1 times, respectively. It was shown that during 18 months of storage, a high rate of viable cells was for the Enterococcus faecium strain and the addition of WPC and barley malt extract (BME) to the samples, where the losses were 11.8% and 11.9%.