Gastrointestinal Passage Research Articles

Isolation and evaluation of Pediococcus acidilactici YH-15 from cat milk: Potential probiotic effects and antimicrobial properties

The study aimed to screen for the possible presence of lactic acid bacteria (LAB) in cat milk in order to evaluate their probiotic properties. The isolates were characterized by biochemical identification, morphological tests and 16S rDNA sequencing. Afterward, gastrointestinal passage, in vitro safety and probiotic properties were evaluated. The results showed that the isolates had 10 strains of Pediococcus acidilactici permitted in the feed additive catalog. The high survival rate in the acid and bile salt resistance test reflected the good strain tolerance of the isolates to the simulated gastrointestinal conditions of the host in vitro. The mean inhibitory diameters of the 10 strains against chloramphenicol and tetracycline were 23.6 mm and 17.4 mm, respectively; none of the hemolytic tests showed α/β hemolytic ring. The bacteriostatic test showed that P. acidilactici YH-9, YH-14 and YH-15 had inhibitory effects on four common pathogenic bacteria, including Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Streptococcus. The adhesion test showed that P. acidilactici YH-15 had good adhesion to HT-29 cells. Based on these results, we concluded that P. acidilactici YH-15 extracted from cat milk has potential application as a clinical probiotic therapy and health care product.

The Effect of Food Matrix Taken with Probiotics on the Survival of Commercial Probiotics in Simulation of Gastrointestinal Digestion

The adequate survival of probiotics in the harsh environment of the gastrointestinal (GI) tract plays a crucial role in the expression of their functional properties. The aim of the present study was to evaluate the survival of commercial probiotics during digestion using a standardised INFOGEST 2.0 model extended with three food matrices simulating three scenarios for the consumption of probiotics: on an empty stomach, with juice, or with food (porridge). All eight products matched the bacterial content stated on the label. After simulated digestion, we observed an average decrease in viability of 1.6 log10 colony forming units (CFU) when the product was co-digested with water, a 2.5 log10 CFU decrease in the presence of juice, and a 1.2 log10 CFU decrease in the presence of porridge. The survival rate of the probiotics was statistically higher in the test samples with porridge (91.8%) than in those with juice (79.0%). For two products, the number of lactobacilli and bifidobacteria strains after digestion was less than <3 × 105 CFU, which can be considered insufficient. The present study has shown that the survival of probiotic strains during GI passage depends not only on their ability to withstand these harsh conditions but may also be influenced by the manufacturing process and by the foods consumed together with the probiotics.

Survival of Probiotic Bacterial Cells in the Upper Gastrointestinal Tract and the Effect of the Surviving Population on the Colonic Microbial Community Activity and Composition.

Many health-promoting effects have been attributed to the intake of probiotic cells. However, it is important that probiotic cells arrive at the site of their activity in a viable state in order to exert their beneficial effects. Careful selection of the appropriate probiotic formulation is therefore required as mainly the type of probiotic species/strain and the administration strategy may affect survival of the probiotic cells during the upper gastrointestinal (GIT) passage. Therefore, the current study implemented Simulator of the Human Microbial Ecosystem (SHIME®) technology to investigate the efficacy of different commercially available probiotic formulations on the survival and culturability of probiotic bacteria during upper GIT passage. Moreover, Colon-on-a-Plate (CoaP™) technology was applied to assess the effect of the surviving probiotic bacteria on the gut microbial community (activity and composition) of three human donors. Significantly greater survival and culturability rates were reported for the delayed-release capsule formulation (>50%) as compared to the powder, liquid, and standard capsule formulations (<1%) (p < 0.05), indicating that the delayed-release capsule was most efficacious in delivering live bacteria cells. Indeed, administration of the delayed-release capsule probiotic digest resulted in enhanced production of SCFAs and shifted gut microbial community composition towards beneficial bacterial species. These results thus indicate that careful selection of the appropriate probiotic formulation and administration strategy is crucial to deliver probiotic cells in a viable state at the site of their activity (distal ileum and colon).

Adaptations in Gastrointestinal Nutrient Absorption and its Determinants During Pregnancy in Monogastric Mammals: A Scoping Review.

Pregnancy increases nutrient demand, but how nutrient uptake and its determinants adapt to facilitate this is unclear. This review aimed to identify and characterize evidence and evidence gaps regarding changes in gastrointestinal nutrient absorption and its determinants during pregnancy in monogastric mammals. A scoping review of peer-reviewed sources was conducted across PubMed, Scopus, Web of Science, Embase, and ProQuest (theses and dissertations) databases. Data extracted included species, pregnancy stages and outcomes. Where sufficient data for a given outcome was available, relative values were summarized graphically or in tables, to allow comparison across pregnancy stages and/or small intestine regions. Searches identified 26 855 sources, of which only 159 were eligible. Mechanistic studies were largely restricted to rodents, and most compared non- and late-pregnant groups, with fewer studies including early- or mid-pregnant groups. During pregnancy, there is some evidence for greater capacity for glucose uptake but unchanged amino acid uptake, and good evidence for increased uptake of calcium, iron, and zinc, and slower gastrointestinal passage of nutrients. The available evidence indicates that acute glucose uptake, gastric emptying, and the activities of sucrase, maltase, and lactase do not change during pregnancy. Gaps in the knowledge include the effects of pregnancy on uptake of specific amino acids, lipids, and most minerals and vitamins. The results indicate that the gastrointestinal tract adapts during pregnancy to facilitate increased nutrient absorption. Additional data is required in order to assess the underlying mechanisms for and impacts on the absorption of many nutrients, as well as to determine the timing of these adaptations.

A Case of Esophagogastric Junction Cancer Treated with Pain Control by Administering Methadone Tablets Through a Gastrostomy.

Introduction: Methadone is used to treat intractable cancer pain when other opioid analgesics are ineffective. Methadone tablets may be difficult to administer in cases of gastrointestinal passage obstruction. However, changing the route of methadone tablet administration is possible. Case Description: The patient, diagnosed with esophagogastric junction cancer with multiple metastases, continued to receive methadone tablets even after not being longer able to take oral medication. Method: Methadone tablets were administered using a simple suspension method via gastrostomy. We measured the respiratory rate during sleep daily. We also measured weekly QTc values using a 12-lead electrocardiogram and methadone blood concentration periodically. No side effects were observed. Conclusion: Using a simple suspension method to administer methadone is a safe pain management method when accompanied by careful monitoring. To date, no study has examined the tube administration safety of methadone tablets. Thus, this case report is of important clinical significance.

Recent Advances in the Understanding of Stress Resistance Mechanisms in Probiotics: Relevance for the Design of Functional Food Systems.

In recent years, more and more scientific community, food producers, and food industry show increased interest in functional foods containing probiotics, which is a big challenge. The consumption of probiotics in the context of a balanced diet through the consumption of functional foods or through the intake of pharmaceutical preparations has proven to contribute to the improvement of human health, even contributing to the prevention of diseases. In order for probiotics to be considered suitable for consumption, they must contain a minimum concentration of viable cells, namely, at least 107 colony forming units of beneficial microbes per gram. Ensuring the viability of bacterial cells until the moment of consumption is the overriding priority of functional probiotic food manufacturers. Probiotic bacteria are subject to stress conditions not only during food manufacturing but also during gastrointestinal passage, which limit or even compromise their functionality. This paper first examines all the stressful conditions faced by probiotic cells in their production stages and related to the conditions present in the bioreactor fermentation and drying processes as well as factors related to the food matrix and storage. The stress situations faced by probiotic microorganisms during the gastrointestinal transit especially during stomach and intestinal residence are also analyzed. In order to understand the adaptation mechanisms of probiotic bacteria to gastrointestinal stress, intrinsic and adaptive mechanisms identified in probiotic strains in response to acid stress and to bile and bile acid stress are analyzed. In addition, improvement strategies for multiple stress tolerance of lactic acid bacteria through directions dealing with stress, accumulation of metabolites, use of protectants, and regulation of technological parameters are examined. Finally, the definition of postbiotics, inanimate microorganisms and/or their components conferring health benefits, is also introduced. Postbiotics include cell lysates, enzymes, and cell wall fragments derived from probiotic bacteria and may represent an alternative to the use of probiotics, when they do not tolerate stressful conditions.

Can a functional cheese spread incorporating Akkermansia muciniphila deliver beneficial physicochemical and biological properties while enhancing probiotic stability and viability during aerobic storage and in vitro digestion?

In the present study, next generation probiotic Akkermansia muciniphila was incorporated into a dairy matrix containing Portuguese whey cheese and Greek-style yoghurt in a proportion of 3.5:1, respectively. Subsequently, this innovative food was characterized in terms of microbiological and physicochemical parameters, total phenolic content and antioxidant, antidiabetic, and antihypertensive activities, as well as its protective effect on A. muciniphila viability during 21 d of refrigerated aerobic storage and when subjected to simulated gastrointestinal passage. The probiotic cheese spread displayed high microbiological quality, low total phenolic content (0.36 mg gallic acid equivalents/g of dried cheese) and interesting biological activities, including antidiabetic (98.10% α-glucosidase inhibition) and antihypertensive (49.18% angiotensin converting enzyme inhibition). Simultaneously, this food ensured a high A. muciniphila viability (>108 CFU/g) during 21 d of refrigerated aerobic storage with subsequent in vitro digestion. Additionally, this probiotic cheese presented a similar profile in terms of texture, color, water activity and pH when compared to the cheese control (without A. muciniphila), suggesting a potentially high acceptance among consumers. In conclusion, the developed cheese spread seems to be a promising and suitable food vector to safeguard A. muciniphila viability during refrigerated aerobic storage for at least 21 d with subsequent gastrointestinal passage.

Identification of safe putative probiotics from various food products.

The objective of this study was to isolate, identify, and assess the safety and functionality in vitro of putative probiotic bacterial strains. Isolation procedures were based on standard methods using elective and selective media. The isolates were identified by comparative 16S rRNA sequencing analysis while their safety was determined according to the safety tests recommended by the FAO/WHO such as antibiotic resistance, hemolysin, and biogenic amine production. Most of the isolates did not pass the in vitro safety tests; therefore, only Lactiplantibacillus plantarum (from ant intestine and cheese), Lacticaseibacillus paracasei (from goat milk and kimchi), Enterococcus faecium (from chili doenjang and vegetables with kimchi ingredients), Limosilactobacillus fermentum (from saliva), and Companilactobacillus alimentarius (from kimchi) were identified and selected for further studies. The isolates were further differentiated by rep-PCR and identified to the strain level by genotypic (16S rRNA) and phenotypic (Gen III) approaches. Subsequently, the strain tolerance to acid and bile was evaluated resulting in good viability after simulated gastrointestinal tract passage. Adhesion to mucin in vitro and the presence of mub, mapA, and ef-tu genes confirmed the adhesive potential of the strains and the results of features associated with adhesion such as hydrophobicity and zeta potential extended the insights. This study reflects the importance of fermented and non-fermented food products as a promising source of lactic acid bacteria with potential probiotic properties. Additionally, it aims to highlight the challenges associated with the selection of safe strains, which often fail in the in vitro tests, thus hindering the possibilities of "uncovering" novel and safe probiotic strains.

Passeio de capivara: evidência de dispersão de plantas aquáticas inteiras

Abstract: The functioning of diverse ecosystems relies on the dispersal processes facilitated by animals, known as zoochory. This ecological process is the only way in which some aquatic species can move between aquatic systems through the terrestrial matrix. Despite its paramount importance, the dispersal mechanisms involving certain vectors, such as mammals, have remained relatively poorly understood. Based on observation of capybaras Hydrochoerus hydrochaeris emerging from a wetland with various aquatic plant species attached to their fur, we hypothesized that these mammals play a crucial role in dispersing aquatic plants. We conducted a controlled experiment and confirmed that capybaras disperse two species of duckweed, Lemna valdiviana and Wolffia columbiana, through both endozoochory and epizoochory. The discovery of entire plant dispersal is noteworthy because it is not dependent on the season and does not rely on the production of specific reproductive diaspores. This study presents pioneering documentation of capybaras capacity to disperse entire plants through their gastrointestinal passage and offers further evidence of their role in epizoochory within neotropical wetlands.

Possible role of neuropeptide Y on zymosan- and lipopolysaccharide-induced change in gastrointestinal feed passage via the medulla oblongata in chicks

Zymosan is a fungi-derived pathogen-associated molecular pattern. It activates the immune system and induces the reduction of feed passage rate in the gastrointestinal tract of vertebrates including birds. However, the mechanism mediating the zymosan-induced inhibition of feed passage in the gastrointestinal tract remains unknown. Since the medulla oblongata regulates the digestive function, it is plausible that the medulla oblongata is involved in the zymosan-induced inhibition of feed passage. The present study was performed to identify the genes that were affected by zymosan within the medulla oblongata of chicks (Gallus gallus) using an RNA sequencing approach. We found that mRNAs of several bioactive molecules including neuropeptide Y (NPY) were increased with an intraperitoneal (IP) injection of zymosan. The increase of mRNA expression of NPY in the medulla oblongata was also observed after the IP injection of lipopolysaccharide, derived from gram-negative bacteria. These results suggest that medullary NPY is associated with physiological changes during fungal and bacterial infection. Furthermore, we found that intracerebroventricular injection of NPY and its receptor agonists reduced the feed passage from the crop. Additionally, the injection of NPY reduced the feed passage from the proventriculus to lower digestive tract. NPY also suppressed the activity of duodenal activities of amylase and trypsin. The present study suggests that fungi- and bacteria-induced activation of the immune system may activate the NPY neurons in the medulla oblongata and thereby reduce the digestive function in chicks.

In vitro digestion of SARS-CoV-2 contaminated berries reveals high inactivation of infectious virus during gastrointestinal passage.

During the pandemic, news outlets occasionally reported on the detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) RNA on various foods, raising concerns over contaminated foods initiating infections. Coronavirus disease 2019 (COVID-19) patients often experience gastrointestinal symptoms and shed SARS-CoV-2 RNA in their feces. In addition, active virus replication in the gastrointestinal tract was shown; however, infectious viruses were rarely detected in feces. We previously showed that SARS-CoV-2 remained infectious on frozen berries for at least a month. Here, in vitro digestion models showed that SARS-CoV-2 on berries exhibits minimal inactivation at the oral phase and the virus may escape gastric inactivation early during feeding. However, high intestinal inactivation of the virus on berries suggested that SARS-CoV-2 was less likely to initiate infection in the small intestine. In contrast, the oral cavity is a potential site where infection might be initiated, providing more input for the gastrointestinal tract. High intestinal inactivation might explain the difficulty of detecting infectious SARS-CoV-2 in feces but not of virus RNA.

A Commercial Clay-Based Material as a Carrier for Targeted Lysozyme Delivery in Animal Feed.

The controlled supply of bioactive molecules is a subject of debate in animal nutrition. The release of bioactive molecules in the target organ, in this case the intestine, results in improved feed, as well as having a lower environmental impact. However, the degradation of bioactive molecules' in transit in the gastrointestinal passage is still an unresolved issue. This paper discusses the feasibility of a simple and cost-effective procedure to bypass the degradation problem. A solid/liquid adsorption procedure was applied, and the operating parameters (pH, reaction time, and LY initial concentration) were studied. Lysozyme is used in this work as a representative bioactive molecule, while Adsorbo®, a commercial mixture of clay minerals and zeolites which meets current feed regulations, is used as the carrier. A maximum LY loading of 32 mgLY/gAD (LY(32)-AD) was obtained, with fixing pH in the range 7.5-8, initial LY content at 37.5 mgLY/gAD, and reaction time at 30 min. A full characterisation of the hybrid organoclay highlighted that LY molecules were homogeneously spread on the carrier's surface, where the LY-carrier interaction was mainly due to charge interaction. Preliminary release tests performed on the LY(32)-AD synthesised sample showed a higher releasing capacity, raising the pH from 3 to 7. In addition, a preliminary Trolox equivalent antioxidant capacity (TEAC) assay showed an antioxidant capacity for the LY of 1.47 ± 0.18 µmol TroloxEq/g with an inhibition percentage of 33.20 ± 3.94%.

Akkermansia muciniphila Encapsulated in Calcium-Alginate Hydrogelated Matrix: Viability and Stability over Aerobic Storage and Simulated Gastrointestinal Conditions.

Akkermansia muciniphila is considered a next-generation probiotic to be incorporated in new food and pharmaceutical formulations. Effective delivery systems are required to ensure high probiotic viability and stability during product manufacture, shelf-life, and post-consumption, namely, throughout digestion. Hydrogelated matrices have demonstrated promising potential in this dominion. Hence, this work aimed to evaluate the effect of a calcium-alginate hydrogelated matrix on A. muciniphila viability during 28-days refrigerated aerobic storage and when exposed to simulated gastrointestinal conditions, in comparison with that of free cells. Akkermansia muciniphila was successfully encapsulated in the calcium-alginate matrix via extrusion (60% encapsulation yield). Furthermore, encapsulated A. muciniphila exhibited high stability (a loss in viability lower than 0.2 log-cycle) after 28-days of refrigerated aerobic storage, maintaining its viability around 108 CFU/g. Prominently, as the storage time increased, encapsulated A. muciniphila revealed higher viability and stability regarding in vitro gastrointestinal conditions than free cells. This suggests that this encapsulation method may attenuate the detrimental effects of prolonged aerobic storage with a subsequent gastrointestinal passage. In conclusion, encapsulation via extrusion using a calcium-alginate hydrogelated matrix seems to be a promising and adequate strategy for safeguarding A. muciniphila from adverse conditions encountered during refrigerated aerobic storage and when exposed to the gastrointestinal passage.

Hazards Associated With Nanotechnology in Clinical Dentistry.

Nanotechnology has transformed the field of dentistry with immense potential to provide comprehensive oral health care using nanomaterials, advanced clinical tools, and devices. New materials with superior properties can be developed using nanotechnology by making use of their atomic or molecular properties. Although there are numerous ways in which nanomaterials impact our health, the primary causeis that they comprise chemicals that may have an inadvertent reaction in the body. Moreover, they are used on a daily basis, increasing human contact with them. It is observed to be smaller in size than the physiological barrier in our bodies, making it much simpler for them to pass through and enter the body and they are being used more frequently. It is observed to be smaller in size than the physiological barrier in our bodies, making it much simpler for them to pass through and enter the body and being used more frequently. Although there are numerous ways in which nanomaterials impact our health, the primary causeis they comprise chemicals that may have an inadvertent reaction in the body. The review discusses various types of toxicity, including the cytotoxicity of composites, carbon nanoparticles, silver nanoparticles (SNPs), and quantum dots. It also covers genotoxicity, the effect of nanoparticles on salivary secretion, oral and gastrointestinal mucosa passage of nanoparticles, the tooth surface microenvironment, and interactions with engineered nanomaterials (ENMs). It is concluded that there is scarce information regarding the presence of chemicals that are released from nanoparticles used in dental materials. Nanotechnology is at an infant stage, although it has progressed by leaps and bounds, hailing a new age that provides better treatment modalities in various branches of dentistry. Although the development and application of nanodentistry are of considerable interest, knowledge regarding the possible toxicity of such materials must be meticulously evaluated, and potential benefits must be weighed against the risks to identify potential gaps in the safety assessment. Further research is needed on workplace exposure to nanoparticles in dentistry.

Evaluation of Bile Salts on the Survival and Modulation of Virulence of Aliarcobacter butzleri.

Aliarcobacter butzleri is a Gram-negative bacterium associated with infections of the gastrointestinal tract and widely distributed in various environments. For successful infection, A. butzleri should be able to tolerate various stresses during gastrointestinal passage, such as bile. Bile represents an antimicrobial host barrier that acts against external noxious agents and consists of a variety of bile salts. The intestinal bile salts act as detergents involved in the antimicrobial host defense; although, on the bacterial side, they could also serve as a signal to activate virulence mechanisms. The aim of this work was to understand the effects of bile salts on the survival and virulence of A. butzleri. In our study, A. butzleri was able to survive in the presence of human physiological concentrations of bile salts. Regarding the virulence features, an increase in cellular hydrophobicity, a decrease in motility and expression of flaA gene, as well as an increase in biofilm formation with a concomitant change in the type of biofilm structure were observed in the presence of sub-inhibitory concentration of bile salts. Concerning adhesion and invasion ability, no significant difference was observed. Overall, the results demonstrated that A. butzleri is able to survive in physiological concentrations of bile salts and that exposure to bile salts could change its virulence mechanisms.

Anti-obesity potential of a yogurt functionalized with a CLNA-rich pomegranate oil

Pomegranate oil is rich in conjugated linolenic acids, compounds which have attracted attention due to their potential applicability in obesity management as they are capable of modulating leptin and adiponectin secretion and regulate fatty acids storage and glucose metabolism. Among the possible bioactive foodstuffs capable of delivering these bioactive compounds yogurts have shown potential. Thus, the purpose of this work was to develop functional yogurts through the addition of pomegranate oil either in its free or encapsulated (used as a protective strategy against oxidation and gastrointestinal tract passage) forms. To that end, the pomegranate oil (free and encapsulated) was incorporated in yogurt and the functional yogurt capacity to modulate hepatic lipid accumulation, adipocyte metabolism (in terms of lipolysis, and adipokines secretion) and immune response was evaluated. The results obtained showed that the pomegranate oil’s incorporation led to an improvement in the yogurts' nutritional values, with a reduction in its atherogenic and thrombogenic indexes (more than 78% for atherogenic and 76% for thrombogenic index) and an enhancement of its hypocholesterolemic/hypercholesterolemic ratio (more than 62%) when compared to the control yogurt. Furthermore, data also showed for the first time how these functional yogurts promoted modulation of metabolic processes post GIT as they were capable of reducing by 40% triglycerides accumulation in steatosis-induced Hep G2 cells and by 30 % in differentiated adipocytes. Moreover, samples also showed a capacity to modulate the leptin and adiponectin secretion (56 % of increase in adiponectin) and reduce the IL-6 secretion (ca 44%) and TNF-α (ca 12%) in LPS-stimulated cells. Thus, the CLNA-rich yogurt here developed showed potential as a viable nutraceutical alternative for obesity management.

Development of a microencapsulated probiotic delivery system with whey, xanthan, and pectin.

Pediococcus pentosaceus is a lactic acid bacterium that has probiotic potential proven by studies. However, its viability can be affected by adverse conditions such as storage, heat stress, and even gastrointestinal passage. Thus, the aim of the present study was to microencapsulate and characterize microcapsules obtained by spray drying and produced only with whey powder (W) or whey powder combined with pectin (WP) or xanthan (WX) in the protection of P. pentosaceus P107. In the storage test at temperatures of - 20°C and 4°C, the most viable microcapsule was WP (whey powder and pectin), although WX (whey powder and xanthan) presented better stability at 25°C. In addition, WX did not show stability to ensure probiotic potential (< 6 Log CFUmL-1) for 110days and the microcapsule W (whey powder) maintained probiotic viability at the three temperatures (- 20°C, 4°C, and 25°C) for 180days. In the exposition to simulated gastrointestinal juice, the WX microcapsule showed the best results in all tested conditions, presenting high cellular viability. For the thermal resistance test, WP microcapsule was shown to be efficient in the protection of P. pentosaceus P107 cells. The Fourier transform infrared spectroscopy (FTIR) results showed that there was no chemical interaction between microcapsules of whey powder combined with xanthan or pectin. The three microcapsules produced were able to protect the cell viability of the microorganism, as well as the drying parameters were adequate for the microcapsules produced in this study.

Contrast-Enhanced Multispectral Optoacoustic Tomography for Functional Assessment of the Gastrointestinal Tract.

Real-time imaging and functional assessment of the intestinal tract and its transit pose a significant challenge to conventional clinical diagnostic methods. Multispectral optoacoustic tomography (MSOT), a molecular-sensitive imaging technology, offers the potential to visualize endogenous and exogenous chromophores in deep tissue. Herein, a novel approach using the orally administered clinical-approved fluorescent dye indocyanine green (ICG) for bedside, non-ionizing evaluation of gastrointestinal passage is presented. The authors are able to show the detectability and stability of ICG in phantom experiments. Furthermore, ten healthy subjects underwent MSOT imaging at multiple time points over eight hours after ingestion of a standardized meal with and without ICG. ICG signals can be visualized and quantified in different intestinal segments, while its excretion is confirmed by fluorescent imaging of stool samples. These findings indicate that contrast-enhanced MSOT (CE-MSOT) provides a translatable real-time imaging approach for functional assessment of the gastrointestinal tract.

Production of GABA in milk fermented by Bifidobacterium adolescentis strains selected on the bases of their technological and gastrointestinal performance

There is an increasing interest in producing foods enriched in gamma-aminobutyric acid (GABA), due to their purported health promoting attributes. GABA is the main inhibitor neurotransmitter of the central nervous system, and several microbial species are capable to produce it through decarboxylation of glutamate. Among them, several lactic acid bacteria species have been previously investigated as an appealing alternative to produce GABA enriched foods via microbial fermentation. In this work we report for the first time an investigation into the possibility of utilizing high GABA-producing Bifidobacterium adolescentis strains as a mean to produce fermented probiotic milks naturally enriched in GABA. To this end, in silico and in vitro analyses were conducted in a collection of GABA-producing B. adolescentis strains, with the main goal to scrutinize their metabolic and safety traits, including antibiotic resistance patterns, as well as their technological robustness and performance to survive a simulated gastrointestinal passage. One of the strains, IPLA60004, exhibited better survival to lyophilization and cold storage (for up to 4 weeks at 4 °C), as well as survival to gastrointestinal passage, as compared to the other strains under investigation. Besides, the elaboration of milk drinks fermented with this strain, yielded products with the highest GABA concentration and viable bifidobacterial cell counts, achieving conversion rates of the precursor, monosodium glutamate (GMS), up to 70 %. To our knowledge, this is the first report on the elaboration of GABA enriched milks through fermentation with B. adolescentis.

The Survival of Psychobiotics in Fermented Food and the Gastrointestinal Tract: A Review.

In recent years, scientists have been particularly interested in the gut-brain axis, as well as the impact of probiotics on the nervous system. This has led to the creation of the concept of psychobiotics. The present review describes the mechanisms of action of psychobiotics, their use in food products, and their viability and survival during gastrointestinal passage. Fermented foods have a high potential of delivering probiotic strains, including psychobiotic ones. However, it is important that the micro-organisms remain viable in concentrations ranging from about 106 to 109 CFU/mL during processing, storage, and digestion. Reports indicate that a wide variety of dairy and plant-based products can be effective carriers for psychobiotics. Nonetheless, bacterial viability is closely related to the type of food matrix and the micro-organism strain. Studies conducted in laboratory conditions have shown promising results in terms of the therapeutic properties and viability of probiotics. Because human research in this field is still limited, it is necessary to broaden our understanding of the survival of probiotic strains in the human digestive tract, their resistance to gastric and pancreatic enzymes, and their ability to colonize the microbiota.