Marcin Kruk

Nanoplastics have been detected in food matrices and food-contact materials, yet data on the biological consequences of dietary nano-scale plastic exposure remain limited. We evaluated the effects of oral administration of polystyrene nanoparticles (1 mg/kg bw), silver nanoparticles (1 mg/kg bw), their co-exposure, and polyethylene nanoparticles (0.5 μg/kg bw) isolated from commercial rice packaging in male and female Wistar rats. After 28 days, colonic immune cell populations, antioxidant parameters, gut microbiota composition, short-chain fatty acids, and intestinal metabolomic profiles were analyzed. Exposure to polyethylene nanoparticles derived from food packaging and polystyrene nanoparticles significantly altered lymphocyte distributions, reduced total antioxidant status, modified microbiota structure, and affected metabolic pathways associated with steroid biosynthesis and inflammatory regulation. Several responses exhibited sex-specific patterns. Co-exposure with silver nanoparticles further influenced microbial metabolites. These findings demonstrate that dietary exposure to nano-sized plastic particles from food-contact materials induces measurable biochemical and metabolic alterations in the colon.

Background: The transfer of human intestinal microbiota from in vivo to in vitro conditions alters its structure. This transition may trigger functional changes in the microbial community, such as its ability to produce short-chain fatty acids (SCFAs) and lactate. Methods: This study evaluated SCFAs and lactate profiles in the dynamic simulator and in the feces of a human volunteer who donated a sample for the inoculation of the system. Changes in SCFA and lactate levels were monitored over a 28-day dietary intervention and a parallel 14-day probiotic supplementation. Results: Microbial and dietary variation were not significant predictors of variability in SCFA and lactate profiles. In contrast, culturing environment and probiotic intervention exerted significant effects on SCFAs and lactate. The probiotic intervention appeared to influence SCFA and lactate profiles under in vitro conditions, whereas no similar effect was observed in vivo. Furthermore, the abundance of individual microbial genera was mostly weakly correlated with SCFA and lactate levels, and the direction of these correlations was inconsistent across two microbiota culturing environments. Conclusions: Our findings suggest that structural changes in the microbiota during its transfer from in vivo to in vitro conditions are accompanied by alterations in microbial functions, such as SCFA and lactate levels or response to interventions. However, these responses align with data from other human studies, supporting the ability of dynamic in vitro models to simulate key functions of the intestinal microbiota. Further optimization is required to accurately model personalized microbiota responses.

Kombucha is a fermented tea beverage produced using SCOBY and is recognized for its potential health-promoting properties. This study investigated the effects of fermentation substrate and the geographic origin of the SCOBY culture on the microbiological, physicochemical, antioxidant, and antibacterial properties of Kombucha and Kombucha-like beverages produced from black tea, milk, and rice. A 72 h fermentation period was selected to enable a direct comparison of SCOBY performance across the different substrates. Tea- and milk-based substrates supported greater microbial growth, with total viable counts reaching approximately 6.0–8.0 log CFU/mL, whereas the rice-based beverage showed limited microbial development. The Polish SCOBY culture produced greater acidification, with pH values ranging from approximately 3.66 to 4.36, and exhibited stronger antibacterial activity, particularly against Escherichia coli, which was the most susceptible of the tested strains. HPLC analysis revealed distinct organic acid profiles among the fermented beverages. Tea-based Kombucha contained substantial amounts of acetic, lactic, and gluconic acids and exhibited the highest antioxidant activity. Total phenolic content was positively correlated with antioxidant capacity. In contrast, the rice-based beverage showed the lowest antioxidant activity. Significant differences in microbial growth and metabolite profiles were also observed between the Polish and Italian SCOBY cultures, indicating that culture origin influenced the fermentation pathways and the resulting properties of the beverages. Overall, the findings confirm the suitability of black tea as a substrate for Kombucha fermentation. They also indicate that alternative fermentation substrates, such as milk and rice, may be used to develop fermented beverages with distinct functional characteristics, although their antioxidant potential may be lower than that of tea-based Kombucha.

Background/Objectives: The microbiota–gut–brain axis (MGBA) plays a pivotal role in cognitive function, making psychobiotics a promising strategy for managing neurodegenerative diseases. Lactic acid bacteria (LAB) from traditional fermented foods represent a valuable source of candidate strains, and multi-strain consortia may offer enhanced therapeutic efficacy through synergistic effects. This study evaluated the functional and psychobiotic potential of three lactic acid bacteria (LAB) strains isolated from fermented foods, assessed as monocultures and a multi-strain consortium (MIX). Methods: The research encompassed an initial screening of the individual strains and the MIX, assessing their adhesion to mucin, stability in a static in vitro digestion model, and amino acid profiling. Subsequently, the LAB MIX underwent long-term evaluation in a dynamic gastrointestinal model (SHIME^®) inoculated with microbiota from a patient with Alzheimer’s disease, during which alterations in gut microbiota composition and amino acid metabolism were analyzed. Results: The LAB MIX demonstrated high stability under digestive stress and effective mucoadhesive properties. Furthermore, the consortium demonstrated a distinct metabolic signature, driving enhanced functional effects that complemented or exceeded those observed in individual monocultures. In the SHIME^® model, the MIX induced significant, site-specific shifts in microbial composition, notably increasing lactobacilli abundance. These taxonomic changes correlated with an enriched metabolic profile, including elevated levels of GABA precursors and amino acids with antioxidant potential, which are crucial for MGBA modulation. Conclusions: These results identify the LAB consortium as a compelling psychobiotic candidate. Further in-depth in vivo and clinical studies are required to validate its therapeutic potential for MGBA modulation.

Background/Objectives: With increasing knowledge of the role of the microbiota in health and disease, the need for the reliable simulation of its behavior in response to various factors, such as diet and probiotic administration in in vitro conditions, has emerged. Although many studies utilize developed systems, data on how accurately these systems represent individual microbiota responses are scarce. Methods: In the present study, the Simulator of Human Intestinal Microbial Ecosystem (SHIME^®) was exposed to experimental conditions mimicking the application of probiotics and dietary changes in the study participant. Next-generation 16S rRNA sequencing was used to reveal the structure of the microbial communities in the analyzed samples. Results: Analysis of 17 samples revealed that predominantly diet and, to a lesser extent, probiotics had a divergent effect on the microbiota’s fluctuations dependent on the culture environment. Despite this, results from both in vitro and in vivo conditions aligned well with previously published data on the expected impact of dietary changes on the intestinal microbial community. Conclusions: The anecdotal evidence presented in this study suggested that current in vitro technology enables the reproduction of some of the microbiota responses that are well known from in vivo research. However, further work is required to enable simulations of an individual microbiota.

An extensive experimental study of trivalent iron (Fe3+) ions in orthorhombic lithium gallate nanocrystals was undertaken. Various spectroscopic methods, such as Raman spectroscopy, extended X-ray absorption fine structure, the Mössbauer effect, electron paramagnetic resonance, photoluminescence, thermoluminescence, and cathodoluminescence were used to investigate the synthesized phosphor. This study revealed the existence of multiple Fe3+ sites, out of which the tetrahedral sites are preferentially occupied. Extensive optical studies showed that the Fe3+ doped lithium gallate phosphor is a promising candidate for various luminescence and thermoluminescence-related applications in the near-infrared regime.

Coffee is a beverage that contains a high concentration of bioactive compounds, particularly polyphenols. These compounds significantly contribute to the polyphenol intake in the diet and have been shown to have beneficial effects on consumer health. The objective of this research was to conduct a comparative analysis of the polyphenolic composition of coffee beans and infusions obtained from coffee beans sourced from both organic and conventional farming practices while taking into consideration variations in roast intensity and geographical origin. The lyophilized coffee grounds and infusions derived from these grounds were also subjected to analysis. The antioxidant activity was measured by using the radical ABTS, and the quantitative and qualitative analysis of polyphenolic compounds was conducted by HPLC. The conventional coffee samples were richer in chlorogenic acid, catechin, and caffeic acid. However, the coffee beans from organic farming contained more gallic acid, epigallocatechin gallate, and quercetin than those grown conventionally. We did not observe significant differences among the coffee plant production sites in Ethiopia, Sumatra, and Peru, but Peru had the poorest amount of polyphenols when compared to Ethiopia and Sumatra. Coffee infusions prepared from organic coffee beans were characterized by a significantly high sum of identified polyphenols. A higher content of caffeine was observed in the organic coffee bean samples than in the conventional coffee bean samples. Conventional coffee beans were characterized by stronger antioxidant activity than organic beans. Coffees from different parts of the world were characterized by different profiles of polyphenol compounds. Moreover, the coffee beans from Ethiopia were characterized by the highest caffeine content. However, among the different geographical areas of coffee beans, the highest antioxidant activity was detected in the coffee beans from Sumatra. Coffee grounds also have the potential to be used as compounds for the cultivation of horticultural plants, and they can be used as a source of numerous health-promoting compounds in the food and cosmetics industries.