The article presents the results of research into the biotechnological processing of collagencontaining raw materials (bovine rumina) to create functional foods. The patterns of biotransformation of collagen-containing raw materials by activated cultures of probiotic microorganisms (Bifidobacterium longum B379 M, Propionibacterium shermanii KM 186 and Lactobacillus helveticus Н17-18) have been studied and theoretically substantiated. It is noted that bovine rumina, following preliminary heat treatment, comprise a good nutrient medium for the development of probiotic cultures. It was revealed that low-molecular compounds formed during the heat treatment of rumina possess prebiotic properties that stimulate the growth of microorganisms. It was established that after 5–8 hours of cultivation, the number of viable cells of the studied cultures in the collagen substrate increases to 10 9 –10 10 CFU / g. It is noted that the biomodification of rumina improves their organoleptic properties and consistency, causing it to become succulent, soft and ductile. Biotransformation of collagen-containing raw materials by probiotic microorganisms leads to a significant increase in amino acids in hydrolysates in comparison with the control sample. The greatest increase in amino acids is observed during the fermentation of collagen Lactobacillus helveticus H17-18, which indicates a higher proteolytic activity of this culture. It was shown that the rumen microstructure undergoes changes under the action of probiotic microorganisms in comparison with the initial state (the muscle carcass becomes thinner and looser, as well as undergoing change in terms of the structure of its morphological elements). As a result of the research, a fundamentally new scheme of biotechnological processing of collagen-containing raw materials was developed. The obtained results open up broad prospects for the creation of BAA-synbiotics and food products intended for functional nutrition.