This study investigates the fermentation of Malva sylvestris aerial parts using three lactic acid bacteria: Lactiplantibacillus plantarum 299V, Pediococcus acidilactici IRZ12B, and Lacticaseibacillus rhamnosus GG. The fermentation process resulted in a notable increase in microbial counts of LAB populations, production of organic acids, reduction of antinutritional factors such as tannins, and enhancement the bioavailability of some essential minerals. Post-fermentation analyses revealed a threefold increase in total phenolic content compared to the non-fermented extract. Antioxidant activity also showed a substantial enhancement, with L. plantarum 299V and P. acidilactici IRZ12B nearly doubling the DPPH inhibition percentage, while L. rhamnosus GG exhibited no improvement. Furthermore, antimicrobial activity varied among strains, with P. acidilactici IRZ12B and L. rhamnosus GG effectively inhibiting Y. enterocolitica growth, while all fermented samples significantly reduced S. enterica proliferation. These findings support the use of lactic acid bacteria fermentation as a bioprocess to improve the phytochemical profile of malva, with potential therapeutic applications. Furthermore, the optimized fermentation conditions could facilitate the incorporation of fermented malva as a functional ingredient in plant-based foods, aligning with the growing consumer demand for health-oriented products. Graphical Abstract

Kombucha, a fermented tea beverage, is gaining popularity due to its rich content of bioactive compounds and associated health benefits. Kombucha fermentation involves a complex microbial consortium, including acetic acid bacteria, lactic acid bacteria, and yeasts, that works synergistically to enhance its nutritional and functional properties. Key compounds produced during fermentation provide antioxidant, anti-inflammatory, and antimicrobial benefits. Despite its well-documented health-promoting properties, limited research exists on how human digestion influences the stability and functionality of kombucha bioactive components. This study investigated how digestion impacts kombucha made from green and black teas, focusing on free amino acid content, antioxidant activity, antimicrobial potential, and microbiota viability. Results showed that digestion significantly increased free amino acids, as fermentation released peptides suitable for gastrointestinal digestion. However, L-theanine, a beneficial tea compound, was no longer detectable after fermentation and digestion, suggesting limited bioaccessibility. Digested kombucha exhibited higher antioxidant activity and stronger antimicrobial effects compared to undigested tea. Moreover, culture-dependent and PMA-based sequencing confirmed the survival of viable microbial strains through simulated gastrointestinal conditions, suggesting the potential of kombucha as a source of live, functional microbes. These findings support the role of kombucha as a natural functional beverage whose health benefits not only persist but may be enhanced after digestion.

Streptococcus thermophilus is widely used in dairy fermentation as a starter culture for yogurt and cheese production. Many strains are endowed with potential probiotic properties; however, since they might not survive in adequate amounts after transit through the human gastrointestinal tract, it is advisable to improve cell survivability during this passage. The present study evaluates the use of 2′-fucosyllactose, a prebiotic molecule from human milk, compared with other known molecules, such as gelatin and inulin, to form alginate-based microcapsules to fulfill these requirements. Such microcapsules, obtained by the extrusion technique, were evaluated in terms of encapsulation efficiency, storage stability, gastrointestinal condition resistance, and cell release kinetics. Results reveal that microcapsules made using 2′-fucosyllactose and those with inulin resulted in the most efficient structure to protect S. thermophilus strain TH982 under simulated gastrointestinal conditions (less than 0.45 log CFU/g decrease for both agents). In addition, a prompt and abundant release of encapsulated cells was detected after only 30 min from microcapsules made with sodium alginate plus 2′-fucosyllactose in simulated gastrointestinal fluid (more than 90% of the cells). These encouraging results represent the first report on the effects of 2′-fucosyllactose used as a co-encapsulating agent.

Comprehensive evaluation of antibiotic susceptibility patterns in Lactiplantibacillus plantarum strains isolated from grape marc, based on genomic and phenotypic assessment. We assessed the antibiotic resistance-susceptibility patterns of twenty L. plantarum strains for sixteen antibiotics. Genomes of relevant strains were sequenced for in-silico assessment and comparative genomic analysis. Results showed high MIC values for spectinomycin, vancomycin and carbenicillin, indicating natural resistance to these antibiotics. Besides, these strains revealed MIC values for ampicillin higher than previously established by the EFSA, indicating the possible presence of acquired resistance genes in the genomes. However, genomic analysis by complete genome sequencing did not reveal presence of ampicillin resistance genes. Comparative genomic analysis between our strains and other L. plantarum genomes present in the literature showed several substantial genomic differences, and suggested the need to adjust the cut-off value for ampicillin in L. plantarum. However, further sequence analysis will reveal how these strains have acquired antibiotic resistance.