Saccharomyces cerevisiae is a sustainable yeast with many applications in the food industry. Here, we study the use of a Saccharomyces cerevisiae model composed of three different industrial strains (a wine, a beer and a baker’s strain) to assess the antifungal activity of three organic plant-based extracts (Hypericum perforatum 10% w/w, Pistacia lentiscus var. Chia 20% w/w and Rosmarinus officinalis 6% w/w). Three different methods were employed (agar disc diffusion, spot assay, and growth curve analysis). Only the Rosmarinus officinalis extract (6% w/w) exhibited inhibitory activity against all the tested yeast strains in the agar disc diffusion method. In the spot assay, all extracts and their carrier oils (sunflower oil and caprylic triglyceride) exerted similar mild antifungal activity. In the growth curve analysis, all extracts significantly lowered the growth rate of the yeasts, but this was not observed for the carrier oils. The results highlighted that it is important to consider more than one method for testing the antimicrobial activity of different compounds. The three yeast strains exhibited differences in their susceptibility to pharmaceutical antifungals, and the beer and baker’s yeasts were resistant to itraconazole. Moreover, polyphenols were detected in all natural extracts which may be linked to their antifungal activity. Our results suggest that we might consider multiple use of these natural extracts in the food industry as food additives or even preservatives to delay food spoilage.

There is an increasing trend to develop beers supplemented with local plant ingredients in order to increase their bioactivity. Carob (Ceratonia siliqua L.) is a xerophytic endemic tree typically found in Mediterranean ecosystems. The aim of this study was to develop a strong dark ale hybrid beer enriched with carob syrup prepared by using carob fruits from the University Campus (Athens, Greece). Three batches of beer were fermented, a dark ale (6% alcohol by volume or ABV) without carob and two strong dark ale beers (8% and 10% ABV) with carob syrup. After the second fermentation (bottle conditioning, 60 days), both carob beers had significantly increased bioactivity. The total phenolic content (176.4 mg GAE/100 mL), the antiradical activity (206.6 mg Trolox Equivalent (TE)/100 mL), and the antioxidant activity (838.2 mg Fe²⁺/100 mL) of the carob strong dark ale 10% ABV beer was increased by more than three times, six times, and eight times, respectively, compared to the standard dark ale (6% ABV) without carob. Moreover, LC-QToF-MS analysis ascertained the enhancement of the phenolic profile of carob beers by ten phenolic compounds compared to the control dark ale beer without carob, indicating their significant antioxidant activity.

This study aimed to develop functional calcium alginate hydrogels incorporating Chlorella vulgaris, carob (Ceratonia siliqua L.), and encapsulated Lactobacillus acidophilus in edible jelly gums with enhanced bioactivity and probiotic viability. Laboratory-prepared jellies containing encapsulated probiotics (encapsulated LAB-Jelly) and those with free cells (LAB-Jelly) were compared with a commercial jelly sample. The formulations were evaluated for phenolic content, antioxidant capacity and antiradical activity, texture, sensory characteristics, and probiotic survival under simulated gastrointestinal conditions. The encapsulated LAB-Jelly exhibited significantly higher total phenolic content (4.6 ± 0.1 mg GAE/g) and antioxidant activity (25.9 ± 0.1 mg Fe⁺²/g) compared to the commercial product, mainly due to the presence of carob and Chlorella. Texture analysis showed lower hardness (21.8 N) but comparable elasticity (89.3%) and cohesiveness (72.8%) comparative to commercial jelly gum, while sensory evaluation confirmed their favorable acceptability and non-perceptible bead presence. Microencapsulation achieved 75% efficiency and improved probiotic survival during gastrointestinal simulation after 18 h (14% reduction in Logcfu/mL compared to 30% of the free probiotics). Overall, the combination of alginate encapsulation, Chlorella, and carob produced edible jelly gums with improved antioxidant and textural properties, offering a promising delivery system for functional foods enriched with probiotics and plant-based bioactives.

The opportunistic pathogenic bacterium C. sakazakii poses a significant infection risk to infants through contaminated powdered infant formulae (PIFs) when proper hygiene and temperature control are neglected during reconstitution. This study aimed to investigate whether the acid-buffering capacity (ABC) of commercially available PIFs enriched with the probiotic strain Bifidobacterium animalis subsp. lactis (BB-12^®) could influence the growth of C. sakazakii. Two PIFs differing in their ABC were reconstituted (RIF), inoculated, and incubated in monoculture and co-culture at 22 °C and 37 °C for 24 h. After 24 h of incubation at 22 °C, regardless of the ABC type of PIF, the population of C. sakazakii in the monoculture was approx. 1.4 log cycles higher than the inoculum, while, in the co-culture, the C. sakazakii count was approx. 0.34 log cycles lower. In contrast, at 37 °C during the 24 h co-culture in the lower ABC infant formula, C. sakazakii was <10 CFU/mL. In all co-culture samples, the pH was significantly lower (p < 0.05) in the PIF with the lower ABC. An analysis of the weak organic acids at 12 and 24 h of incubation revealed that the antimicrobial activity is significantly affected by the final pH value, the type of the weak organic acids, and their ionic–non-ionic ratio, which is formed through the common ion effect.

The present study investigates the antimicrobial, antioxidant, and in vitro antidiabetic potential of cold infusions prepared from different parts of the Greek carob tree (Ceratonia siliqua L.), which is a xerophytic species. Carob samples, including green and ripe pods and leaves, were collected from an urban area of Attica, Greece, and extracted using food-grade solvents (water and a water–ethanol mixture, 90:10, v/v). The extracts were evaluated for antibacterial activity against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538 using automated turbidometry. In addition, total phenolic content and antioxidant and antiradical activities were determined via spectrophotometry; the phenolic profile was analyzed using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QToF-MS), and α-amylase inhibitory activity was assessed through an in vitro assay. All extracts exhibited statistically significant (p < 0.05) bacteriostatic effects, with green pods and leaves showing the highest activity. Ripe pods demonstrated the most potent α-amylase inhibition (up to 96.43%), especially when extracted with water–ethanol mixture (90:10, v/v). Liquid chromatography coupled with tandem quadrupole/time-of-flight mass spectrometry (LC-QToF-MS) analysis revealed a rich phenolic profile across all samples. While carob leaves showed no α-amylase inhibition, their phenolic profile suggests other potential health-related bioactivities. These findings support the development of carob-based functional food products and highlight the nutritional and pharmaceutical potential of this resilient Mediterranean crop.