The nature and interaction of the constituent substances that make up the sour-milk dessert with plant-based fillers have been studied by the method of IR spectroscopy. This method is used to study the diverse nature of substances. The spectral range applied was in the range of 500–4,000 s -1.
It was found that the intensity of functional groups absorption in the range of 2,500–3,500 s-1 is due to the valence vibrations of NH-, CH and S-H-groups, indicating the presence of free organic acids, aromatic substances. In addition, in the spectra of sour-milk dessert with plant-based fillers, an absorption intensity in the range of 1,470–1,335 s-1 is observed, which indicates the presence of soluble pectin. Proteins characteristics in the samples are observed at absorption in the range of 3,300–3,500 cm -1, which is due to the valence vibrations of the N-H bond in the -NH2 groups.
The use of fruits in the form of a freeze-dried powder together with milk protein concentrate in the technology of sour-milk desserts helps reduce the content of free moisture, hence a stable structure.
Sour-milk dessert with plant-based fillers is a system consisting of particles of different dispersion, which will affect its physical and chemical properties. In particular, there is a slight coarsening of whey proteins and redistribution between particles in the range of 1–10 nm and 1–100 nm.
The use of plant-based fillers in the form of a freeze-dried powder in the technology of sour-milk desserts would not only improve its physical and chemical properties but also could make it possible to enrich the product with minerals.
The mineral composition of the sour-milk dessert is marked by the calcium content (122 mg/100 g), potassium (97 mg/100 g), phosphorus (82 mg/100 g), sodium (50 mg/100 g), and sulfur, iron.