Microbial fermentation is a well-known strategy for enhancing the nutraceutical attributes of foods. Among the fermentation outcomes, bioactive peptides (BAPs), short chains of amino acids resulting from proteolytic activity, are emerging as promising components thanks to their bioactivities. Indeed, BAPs offer numerous health benefits, including antimicrobial, antioxidant, antihypertensive, and anti-inflammatory properties. This review focuses on the production of bioactive peptides during the fermentation process, emphasizing how different microbial strains and fermentation conditions influence the quantity and quality of these peptides. Furthermore, it examines the health benefits of BAPs from fermented foods, highlighting their potential in disease prevention and overall health promotion. Additionally, this review addresses the challenges and future directions in this field. This comprehensive overview underscores the promise of fermented foods as sustainable and potent sources of bioactive peptides, with significant implications for developing functional foods and nutraceuticals.

Bee pollen represents one of the most complete natural foods playing an important role in the diet for its health qualities and therapeutic properties. This work aimed to characterize a Tuscan bee pollen by evaluating its phytochemical profile and the in vitro and ex vivo antioxidant activities. The isolation and taxonomic and functional characterization of yeasts in the sample has been also conducted. Finally, the pollen anti-inflammatory potential has been assessed on a TNFα-inflamed human colorectal adenocarcinoma cell line (HT-29). Our results highlighted a good phytochemical composition in terms of polyphenols, flavonoids, flavonols, monomeric anthocyanins, and carotenoids. In addition, we detected good antioxidant activity and radical scavenging capacity by in vitro and ex vivo assays, as well as good antioxidant activity by isolated yeasts. Data showed no cytotoxic effects of bee pollen extracts, with average viability values >80% at each tested dose. Moreover, TNFα treatment did not affect HT-29 viability while upregulating IL-8, COX-2, and ICAM-1 gene expression, otherwise reduced by both doses of bee pollen. In conclusion, our sample represents an interesting functional food and a potential probiotic product, having high phytochemical compound levels and good antioxidant activities, as well as anti-inflammatory effects on the TNFα-inflamed HT-29 cell line.

Millet, a gluten-free cereal, has received attention for its environmental friendliness and higher protein content than other grains. It represents a staple food in many African countries, where fermentation is traditionally used for preserving food products and preparing different cereal-based products. This study aimed to assess the impact of sourdough fermentation on bioactive compounds and antioxidant and anti-inflammatory properties of pearl millet from Burkina Faso. Phenolic compounds were investigated spectrophotometrically and by HPLC-DAD. The antioxidant activity of unfermented (MF) and fermented (FeMF) millet was evaluated in vitro by spectrophotometric and fluorometric assays and ex vivo on oxidized human erythrocytes for hemolysis inhibition. Finally, the potential anti-inflammatory effect of FeMF and MF was evaluated on human adenocarcinoma cell line (HT-29) exposed to TNF-α inflammatory stimulus. Results revealed significantly higher levels of polyphenols, flavonoids, and in vitro antioxidant activity following millet fermentation. Notable differences in phenolic composition between FeMF and MF are observed, with fermentation facilitating the release of bioactive compounds such as gallic acid, quercetin, and rutin. A dose-dependent protection against oxidative hemolysis was observed in both FeMF- and MF-pretreated erythrocytes. Similarly, pretreatment with FeMF significantly reduced the levels of inflammatory markers in TNF-α-treated cells, with effects comparable to those of MF. Fermentation with sourdough represents a simple and low-cost method to improve the bioactive compounds content and in vitro antioxidant activity of millet flour with promising nutraceutical potential.

Bee pollen is produced by honeybees from the agglutination of pollen grains belonging to one or more plant species. Although it is intended to be a nutritional source for the hive, its remarkable concentration of nutrients and phytochemicals, combined with its pleasant organoleptic qualities, makes it appealing for human consumption. This study examined the phytochemical content and the antioxidant and antimicrobial activities of a polyfloral bee pollen collected in Tuscany (Italy). Additionally, its less studied anti-inflammatory potential towards tumor necrosis factor-alpha (TNF-α)-inflamed A549 cells was evaluated to assess its possible use in inflammatory respiratory diseases. Bee pollen extract (BPE) was chemically characterized in terms of total polyphenol (20.2 ± 1.5 mg gallic acid equivalents/g fw), flavonoid (9.22 ± 0.64 mg quercetin equivalents/g fw), and carotenoid (10.4 ± 1.4 µg carotenoids/g fw) contents. BPE exerted good antioxidant and antiradical activities in ferric reducing antioxidant power (38.6 ± 4.5 mg Fe²⁺/g fw), oxygen radical absorbance capacity (433.77 ± 18.95 μmol TE/g fw), and 2,2-diphenyl-1-picrylhydrazyl (EC₅₀ = 613.8 ± 79.2 μg/mL) assays. Additionally, BPE inhibited the growth of Bacillus subtilis and Pseudomonas stutzeri (MIC = 10 mg/mL) in the microdilution assay. When TNF-α-inflamed A549 cells were pretreated with BPE (10 and 50 µg/mL), the upregulated interleukin-8 gene and cyclooxygenase-2 gene and protein expression were significantly attenuated. BPE modulated the nuclear factor-κB signaling pathway by decreasing its active phosphorylated form levels. These encouraging results confirm that honeybee pollen is a valuable health-promoting food that could alleviate the inflammatory component of various chronic pulmonary conditions.

In the sustainability framework, valorization of organic by-products as reservoirs of phytochemicals useful for human health represents a hot topic. Therefore, this study evaluated Norway spruce bark and twigs (NSB, NST), chestnut tree wood (CTW), and pomegranate fruit waste/pomace (PFW) as sources of bioactive compounds by employing green technologies. Microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE), applied individually or sequentially, were optimized by modulating solvent composition, temperature, time, microwave power, and ultrasound amplitude. Hydroalcoholic extraction (50% ethanol) combined with MAE yielded the highest phenolic recovery and antioxidant activity across all matrices. PFW exhibited the highest antioxidant activity assessed through FRAP, ORAC, and DPPH assays. Phytochemical profiling by HPLC-DAD identified stilbenes in spruce extracts, ellagic acid in chestnut wood, and ellagic acid and punicalagins in pomegranate waste as major bioactive constituents. Additionally, NSB and PFW exhibited α-amylase inhibitory activity. Antimicrobial testing demonstrated dose-dependent activity against Gram-positive (Staphylococcus epidermidis and Bacillus subtilis) and Gram-negative (Pseudomonas stutzeri) strains, with PFW exhibiting the strongest inhibition and NSB displaying broad-spectrum effects. Total phenolic content changed moderately after 21 days of storage. These results demonstrate that sustainable extraction enables efficient recovery of bioactive compounds from plant by-products, supporting their further functional, dietary, and medicinal applications.