This study explores the potential probiotic properties of yeasts isolated from various Chilean honeys, focusing on Ulmo, Quillay, and Mountain honeys. Six yeast strains were identified, including Zygosaccharomyces rouxii, Candida sp., Schizosaccharomyces pombe, Rhodosporidiobolus ruineniae, Clavispora lusitaniae, and Metschnikowia chrysoperlae. Phenotypic characterization involved assessing their fermentative performance, ethanol and hops resistance, and cross-resistance. Ethanol concentration emerged as a limiting factor in their fermentative performance. The probiotic potential of these yeasts was evaluated based on resistance to high temperatures, low pH, auto-aggregation capacity, survival in simulated in vitro digestion (INFOGEST method), and antimicrobial activity against pathogens like Escherichia coli, Staphylococcus aureus, and Salmonella enteritidis. Three yeasts, Zygosaccharomyces rouxii, Schizosaccharomyces pombe, and Metschnikowia chrysoperlae, exhibited potential probiotic characteristics by maintaining cell concentrations exceeding 10⁶ CFU/mL after in vitro digestion. They demonstrated fermentative abilities and resistance to ethanol and hops, suggesting their potential as starter cultures in beer production. Despite revealing promising probiotic and technological aspects, further research is necessary to ascertain their viability in producing fermented foods. This study underscores the innovative potential of honey as a source for new probiotic microorganisms and highlights the need for comprehensive investigations into their practical applications in the food industry.

Controlled lactic acid fermentation may be a strategy for valorization of plant matrices such as murta (Ugni molinae Turcz), a Chilean berry rich in phenolic compounds. This study evaluated the effect of fermentation in monoculture with Lactobacillus acidophilus and Lactiplantibacillus plantarum, as well as in coculture, under two optimized conditions (SAW and GDF) on the content, structural profile, and antioxidant capacity of extractable (EP) and hydrolysable (HP) polyphenols in murta juice. High Performance Liquid Chromatography coupled to Quadrupole Time-of-Flight Mass Spectrometry (HPLC-QTOF-MS) analysis identified 59 EP compounds, including methylated and glycosylated derivatives not previously reported in murta, evidencing a fermentation-induced structural reconfiguration. Additionally, 13 compounds (not present in unfermented samples) were identified in the hydrolysable polyphenol fraction, demonstrating the contribution of this constituent to a comprehensive assessment of the murta phenolic profile. The results showed significant increases in extractable polyphenols and their antioxidant activity (FRAP and ABTS) in GDF conditions, highlighting the coculture as the most effective. These findings confirm that using optimized fermentative conditions, particularly in coculture, not only increases the concentration and diversity of phenolic compounds but also underscores the importance of integrating extractable and hydrolysable polyphenol fractions to broaden the utilization of murta juice in developing fermented beverages with enhanced functional properties.

Lactic fermentation modulates polyphenol composition in plant matrices, yet how compositional shifts translate into functional outcomes across extractable (EP) and hydrolyzable (HP) fractions remains unclear. Here, we apply a phenolic–bioactivity connectivity framework to fermented murta (Ugni molinae Turcz) juice, integrating compositional profiling with three functional axes: antimicrobial activity (against Escherichia coli, Salmonella enterica, and Staphylococcus aureus), inhibition of carbohydrate-hydrolyzing enzymes (α-amylase, α-glucosidase) and DPP-IV, and modulation of oxidative stress in Caco-2 cells. Murta juice was fermented with Lactobacillus acidophilus, Lactiplantibacillus plantarum, and a 1:1 coculture under two optimized strategies (GDF and SAW). Principal component analysis separated fermented from unfermented samples (89.7% variance explained) and identified coculture fermentation (MIX-GDF) as the most compositionally distinct treatment. EP fractions drove antimicrobial and α-glucosidase inhibition, whereas HP fractions contributed preferentially to DPP-IV inhibition and intracellular reactive oxygen species (ROS). A bipartite correlation network revealed a dual-functional architecture: specific flavonoid–bioactivity associations governed enzyme inhibition, while diffuse collective interactions shaped antimicrobial responses. These results demonstrate that fermentation-induced phenolic remodeling yields structured, functional outcomes, providing a rational basis for designing fermentation strategies targeting specific bioactivity profiles.