A substantial body of research indicates that the gut microbiota exerts a profound influence on host health. The purpose of this work was to characterize selected, most promising, well-known next-generation probiotics (NGPs) and review the potential applications of the bacteria in food technology. The isolation of gut bacteria with significant health benefits has led to the emergence of NGPs. In contrast to traditional probiotics, these originate directly from the gut microbiota, thereby ensuring their optimal adaptation to the intestinal ecosystem. NGPs exert their effects on the host organism through a variety of mechanisms, including the synthesis of bioactive compounds, modulation of the gut microbiota, and metabolism of substances provided by the host. Several bacterial species have been identified as potential candidates for NGPs, including Akkermansia muciniphila, Faecalibacterium prausnitzii, Bacteroides thetaiotaomicron, Christensenella minuta, and many others. These bacteria have demonstrated the capacity to exert beneficial effects, including the reduction of obesity, type 2 diabetes, metabolic disorders, and even cancers. The greatest limitation to their commercialization is their lack of oxygen tolerance, which presents challenges not only for research but also for their potential application in food. The most optimal approach for their application in food appears to be microencapsulation. Further research is required to establish the safety of NGP supplementation and to protect them from environmental conditions.

The study aimed to develop plant-based model snacks that are high in fibre, contain probiotic bacteria and are convenient for long-term storage. The research focused on selecting a suitable form of probiotic bacteria (active biomass, microencapsulated, freeze-dried), inoculation method (in the base mass or in the filling of a snack) and appropriate storage conditions (4°Cor 20 °C). The potential synbiotic properties were evaluated. The microencapsulated bacteria had the highest survival rate at 4 °C, while the freeze-dried bacteria showed better survival rates at 20 °C. Probiotics had a higher survival rate when enclosed inside snacks with a low water activity (a_w = 0.27) peanut butter filling than in snacks without filling (a_w = 0.53). Enclosing the probiotics in a low a_w filling ensures their survival at ambient temperature for 5 months at a count higher than 6 log CFU/g. The snacks exhibited high antioxidant capacity (average 300 mg ascorbic acid equivalent/100 g), polyphenol content (average 357 mg gallic acid equivalent/100 g) and high fibre content (average 10.2 g/100 g). The sensory analysis showed a high overall quality of the snacks (average 7.1/10 of the conventional units). Furthermore, after six months of storage, significant changes were observed in the antioxidant properties, polyphenol content and texture of the snacks, while their sensory quality remained unchanged. Moreover, a potential synbiotic effect was observed. The method used to assess bacterial growth indicated significantly higher values in the model snacks compared to a control sample. Therefore, this study has effectively addressed the gap in knowledge regarding the survival of probiotics in snacks of this nature.

Background. Brewer's spent grain (BSG) is a by-product of beer production, constituting approx. 85 % of all generated by-products in the brewing industry, primarily utilized for livestock feed. It is characterized by high levels of fiber (40 ÷ 60 %), protein (19 ÷ 30 %), and fat (10 %). The protein occurring in BSG contains all amino acids, including exogenous ones, which are not synthesized by the human body. Results and conclusions. Brewer’s spent grain fiber mainly comprises cellulose, hemicellulose and lignin. Due to various fiber fractions, including arabinoxylan (AXs), it is suspected to possess the ability to modulate the human gut microbiota. In vitro studies conducted so far have demonstrated that BSG and extracted AXs fractions stimulate the growth of health-promoting bacteria such as Bifidobacterium and Lactobacillus, however, they also have the capacity to stimulate bacteria of the Enterobacteriaceae family. Moreover, under the influence of brewer’s spent grain, the abundance of Bacteroides and Firmicutes bacteria decreases, while the abundance of Actinobacteria increases. Additionally, it has been proven in each of the studies that the addition of BSG stimulates the synthesis of short-chain fatty acids, including propionic acid and acetic acid, with acetic acid being the most prominently affected. Brewer's spent grain may enhance the scavenging of free radicals due to the presence of phenolic compounds and increase the antioxidant activity of food. Further research, including studies utilizing a dynamic in vitro digestive system and in vivo investigations, is necessary to confirm the beneficial impact of BSG on human health.