Use of High-Protein Milk Preparations in the Production of Probiotic Fresh Cheeses

The study on the use of skimmed milk and buttermilk separation products obtained by membrane filtration and the Lactobacillus acidophilus LA-5 probiotic culture in the production of fresh cheeses was undertaken. Membrane separation products – micellar casein concentrate (MMC), buttermilk protein concentrate (RMFB), a mixture of micellar casein concentrate and a buttermilk serum protein concentrate (RUFP) – were used in liquid and powder form. Fresh cheeses were produced from fluid protein concentrates or from milk with protein powder addition. A control sample was produced from milk with the addition of skimmed milk powder. Fresh cheeses produced from MCC were characterised by a desirable, high content of protein, calcium, and phosphorus. In turn, magnesium content was highest in fresh cheeses made from RUFP. In all cheeses, Lb. acidophilus LA-5 counts exceeded log 6 cfu/g on the last day of storage (day 21), thus satisfying the criteria for probiotic products. Fresh cheese made from MCC was characterised by the greatest difference in colour relative to the control sample. In addition, cheeses produced from MCC fluid or with the addition of MCC powder were characterised by higher firmness (69.58 and 41.67 N, respectively) relative to the cheese produced from RMFB (3.35–3.37 N) or RUFP (5.89–21.96 N). The power law model accurately predicted the rheological properties of the examined cheeses (R 2 >0.999). All cheeses displayed pseudoplastic flow behaviour, where the storage modulus (G') was higher than the loss modulus (G") and was not dependent on frequency. The fractal analysis revealed that MCC cheeses had the least irregular microstructure with the lowest values of fractal dimension. The use of high-protein preparations in the production of fresh cheeses generally decreased their sensory acceptability. It can be concluded that probiotic fresh cheeses made from skimmed milk and buttermilk separation products with the addition of the Lb. acidophilus LA-5 culture differ in physicochemical properties and sensory attributes.