Development of a plant matrix for adaptation and metabolic activity of probiotic microorganisms in fermented beverage technology

To enhance the shelf life, stability, nutritional completeness, and sensory acceptability of plantbased milk alternatives, advanced “green” technologies, including biotechnological approaches, are being developed and implemented. The aim of this study was to substantiate the use of a plant matrix based on hemp seeds and soybeans as a substrate for the adaptation and metabolic activity of probiotic microorganisms. The complex starter culture “Bifidoplus” and the monoculture Lactobacillus acidophilus were integrated into the plant matrix. Beverage fermentation was carried out for 16 hours at T = 36–38 °C. In the hemp seedbased beverages, the pH level decreased actively from 5.46 to 4.67 between 4 and 12 hours. In the soybeanbased beverages, the pH level decreased actively from 5.28 to 4.55 between 8 and 16 hours. Lactobacillus acidophilus demonstrated the most intensive acid accumulation. The lactic acid content in the beverages increased by 5.0–9.5 times compared to the control. Acidophilic bacteria produced organic acids most intensively, and the soybean matrix proved to be a more favorable substrate for the development of both types of starter cultures. The indicators of beverage viscosity, dry matter content, and protein quantity were positively correlated. The highest values for these indicators were established in soybeanbased beverages fermented with the complex Bifidobacteria starter culture. The highest concentration of polyphenols was detected in soybased beverages fermented with Bifidobacteria, where the concentration of polyphenolic compounds increased by 43.6%. The plant matrix based on soybeans and hemp seeds is a favorable and balanced substrate for the adaptation of bifidobacteria and acidophilic bacteria. Microbial enzymes actively exhibit metabolic activity on the plant substrate, accumulating organic acids, protein components, and enzymes; they contribute to increasing the bioavailability of the native components of the seeds and beans.