Whey proteins are a source of bioactive peptides and contain amino acids that are essential to the human body to properly function. Milk protein preparations used in the production of fermented milk beverages stimulated the growth of Lb. acidophilus LA-5 strain. A supplement of α-lactalbumin added to the whole milk caused the time of curd formation with the use of Lb. acidophilus LA-5 strain to be reduced. After a two week period of cold storage of the fermented milk beverages produced from the whole milk powder, the highest cell count (4.1×107 cfu/ml) of Lactobacillus acidophilus LA-5 strain was reported in the products enriched with WPC 65 added in an amount of 1 %. The beverages produced with a 2 % of WPI added were characterized by the highest values of hardness (1.51 N) and storage modulus G’ (5567 Pa). Along with the increasing concentration of α-la and WPI, the hardness increased of the acid gels produced with the application of Lb. acidophilus LA-5 strains. The fermented milk beverages made from skimmed milk were characterized by higher values of the parameters such as hardness and storage modulus. However, the milk beverages from skimmed milk had higher levels of syneresis compared to beverages from the whole milk. The increase in the amount of milk protein preparations added to the beverages caused the amount of separated whey to gradually decrease. The milk beverages with 2 % of WPI added were characterized by the lowest value of syneresis (1.97 %). The enriching of fermented milk beverages with milk protein preparations improves physical and chemical properties of those beverages, influences the increase in their pro-health values, and gives those products the characteristics of functional beverages.
milk protein preparations, probiotic bacteria, Lactobacillus acidophilus, syneresis, texture