The aim of this article is to review literature data on the terminology, classification and physiological effects of dietary fibers. Results. The scientific studies on the terminology, classification and characteristics of various types of dietary fiber are presented, the sources of dietary fiber and their positive physiological effects are described. Nowadays no consensus definition has been given to the concept of dietary fibers. The authors point to dietary fibers being related to chemical compounds defined by structure, or functional properties, and/or a combination of both structural and functional properties. The authors noted one commonality in these definitions: each mentioned positive physiological effects. The modern classification system for dietary fibers is wide and diverse and can be based on origin, structure of polymers, solubility, ion exchange, sorption or physiological effect. Many studies have shown that dietary fibers can promote human health and help prevent specific chronic diseases that increase mortality and reduce life expectancy. Numerous healthful effects of the dietary fibers have been documented. These include curative and preventive effects for diseases such as obesity, certain types of cancers, cardiovascular diseases, diabetes, and constipation. Conclusion. Fibers are considered before other nutrients to ensure a healthy nutrition. Research continues to contribute new data on the effect of dietary fiber on the human body.

Alginate is widely used in the food industry due to its biodegradability, biocompatibility, and non-toxicity. Protein hydrolysates possess properties important for forming the mechanical characteristics, protective, and barrier properties of the films. The aim of the research was to develop biodegradable alginate-based films with bioactive properties and the optimal structural characteristics when protein hydrolysates were incorporated. The microstructure of the cross-sections of films with 0.5 and 1.0% protein hydrolysates was characterized by smoother and homogeneous surfaces, which indicated the compatibility of sodium alginate and protein hydrolysate. The addition of protein hydrolysate significantly increased the thickness of the film by 0.06 mm and reduced the solubility by 49.4% (p < 0.05). The results showed the high biodegradability of alginate-based films after 2 weeks of storage. With the introduction of protein hydrolysate, changes occurred in the FTIR patterns due to the interaction between the hydroxyl groups of peptides and the alginate, and, consequently, the thermal stability of the alginate films increased. The alginate films with PH positively affected the storage capacity of sweet cherry berries, both at room temperature and under refrigeration conditions. The alginate-based films with protein hydrolysate have improved properties and can serve as an alternative to polypropylene packaging materials.

Fermentation is an economical method for obtaining protein hydrolysates. The purpose of the scientific research was to perform a comprehensive analysis of the physicochemical, technological, and functional properties of protein hydrolysates obtained by microbial fermentation. The research results showed that hydrolysates fermented with propionic acid bacteria and bifidobacteria have better physicochemical and technological indicators compared to the control sample. Significant increases in water-holding and fat-holding capacities (by 1.8–2.1 times and 1.5–2.5 times, respectively), as well as fat-emulsifying ability (by 12.8–29.8%) in experimental samples were found. Hydrolysates obtained by fermentation effectively inhibit the growth of Escherichia coli and Staphylococcus aureus. The thermal analysis showed a sufficiently high-thermal stability of the obtained protein hydrolysates. In hydrolysates fermented by bacterial culture, the removal of physico-mechanical and osmotically bound moisture occurred at temperatures of 110 °C and 115 °C, respectively, and in whey protein hydrolysate at a temperature of 100 °C. The release of chemically bound moisture was observed at a temperature of 170 °C for fermented hydrolysates and at 155 °C for the control sample. The results proved that fermented protein products are characterized by high functional properties, antioxidant and antimicrobial activity, and can be used as natural food additives and preservatives.

Enzymatic processes play a key role in the production of grain-containing food due to their effect on the nutritional properties, rheological characteristics, and contribution to improving the functional and antioxidant proprieties. Eight samples of beverages based on barley grain and hemp seeds were produced (control beverages and beverages fermented by bifidobacteria and propionic acid bacteria). It was found that lactic acid accumulated during fermentation alongside a gradual shift in the pH level in the acidic direction. A comparative analysis of the DPPH activity revealed the highest values for barley-based beverages, ranging from 71.0 to 100.7%, while for the hemp seed-based beverages, the DPPH activity was 64.1–97.9%. The maximum values of DPPH activity were observed during fermentation with a combination of bifidobacteria and propionic acid bacteria concentrates. The highest concentration of polyphenolic compounds and flavonoids was found in barley-based beverages fermented with Propionibacterium freudenreichii (1.26 mg GAE/g and 0.11 mg EQ/g) and a combination of Propionibacterium freudenreichii and Bifidobacterium longum (1.24 mg GAE/g and 0.14 mg EQ/g). Studies have shown an increase in the nutrient content for fermented beverages compared to the control samples. The barley-based beverages exhibited the largest average dynamic particle diameter, and all beverage samples showed a more uniform particle size distribution after microbial fermentation.

In connection with the active growth of poultry processing, the issue of rational use of poultry by-products is urgent. The paper proposes hydrolysis of the gizzards of broiler chickens and hens of the parent stock with bifidobacteria liquid concentrate (BLC) and Propionix liquid concentrated starter culture (Propionix LCSC). The effect of enzymatic treatment on changes in the structural components of the gizzards was studied using scanning electron microscopy (SEM) and determination of the dispersed composition. As a result of the research, the multiple regression equations and the response surfaces were obtained, which describe the optimal parameters of the gizzard´s hydrolysis process. The temperature and the time of hydrolysis are factors that have a significant effect on the degree of hydrolysis. The results of the structural and microscopic analysis confirm the high hydrolysability of the by-products by changing its structure and increasing the number of smaller protein particles. It was found experimentally that the gizzards of hens are more susceptible to the action of probiotic microorganisms’ enzymes compared to the gizzards of broiler chickens.

Zinc is a powerful immunomodulatory trace element, and its deficiency in the body is closely associated with changes in immune functions and viral infections, including SARS-CoV-2, the virus responsible for COVID-19. The creation of new forms of zinc delivery to target cells can make it possible to obtain smart chains of food ingredients. Recent evidence supports the idea that the optimal intake of zinc or bioactive compounds in appropriate supplements should be considered as part of a strategy to generate an immune response in the human body. Therefore, controlling the amount of this element in the diet is especially important for populations at risk of zinc deficiency, who are more susceptible to the severe progression of viral infection and disease, such as COVID-19. Convergent approaches such as micro- and nano-encapsulation develop new ways to treat zinc deficiency and make zinc more bioavailable.