Catarina Teixeira-Guedes

Chestnut shells are an underutilized lignocellulosic resource with high valorisation potential. In this study, a cascading biorefinery approach based on sequential autohydrolysis was developed to convert them into added-value compounds. For this, a first non-isothermal treatment, at temperatures ranging from 120 °C to 200 °C, followed by solid recovery and re-processing at 200 °C (second treatment) was applied. The most promising condition (two-step process at 140 °C, S0 = 1.61 followed by 200 °C, S0 = 3.40) enabled selective biomass fractionation, yielding phenolic- and oligosaccharide-rich liquors with antioxidant and prebiotic potential. Phenolic compounds’ yield increased with temperature, reaching 23.5 ± 1.1 mg/g of biomass, while up to ~50 % of structural carbohydrates were solubilized, predominantly as oligosaccharides. Sequential processing enhanced fraction selectivity, allowing the recovery of ~4.5 g and ~10.3 g of oligosaccharides per 100 g of biomass in the first and second stages, respectively, while limiting the formation of degradation products. The oligosaccharide-rich fractions promoted the growth of probiotic strains, highlighting their potential as functional food ingredients. In parallel, the residual solid fraction exhibited high enzymatic digestibility, with glucan conversion approaching 100 %, enabling its conversion into bioethanol with yields of approximately 69 % under simultaneous saccharification and fermentation conditions. Overall, the proposed approach enabled the recovery of approximately 40 % of the initial biomass as value-added products. These findings demonstrate the feasibility of integrating the production of functional ingredients and biofuels within a single process, supporting the development of sustainable and circular biomass valorisation pathways for agro-industrial residues.

The modulation of the intestinal microbiota by dairy-derived product consumption is being explored as an innovative approach to fight colorectal cancer.

Colorectal cancer (CRC) is one of the most common malignancies and one of the leading causes of cancer-related death worldwide, urging the need for new and more efficient therapeutic approaches. Ruthenium complexes have emerged as attractive alternatives to traditional platinum-based compounds in the treatment of CRC. This work aims to evaluate anti-CRC properties, as well as to identify the mechanisms of action of ruthenium complexes with the general formula [Ru(η⁵-C₅H₄R)(PPh₃)(4,4′-R′-2,2′-bipyridine)][CF₃SO₃], where R = CH₃, CHO or CH₂OH and R′ = H, CH₃, CH₂OH, or dibiotin ester. The complexes (Ru 1–7) displayed high bioactivity, as shown by low IC₅₀ concentrations against CRC cells, namely, RKO and SW480. Four of the most promising ruthenium complexes (Ru 2, 5–7) were phenotypically characterized and were shown to inhibit cell viability by decreasing cell proliferation, inducing cell cycle arrest, and increasing apoptosis. These findings were in accordance with the inhibition of MEK/ERK and PI3K/AKT signaling pathways. Ruthenium complexes also led to a decrease in cellular clonogenic ability and cell migration, which was associated with the disruption of F-actin cytoskeleton integrity. Here, we demonstrated that ruthenium complexes, especially Ru7, have a high anticancer effect against CRC cells and are promising drugs to be used as a new therapeutical strategy for CRC treatment.

Legumes are a rich source of a wide range of compounds that may represent an important tool to overcome gut dysbiosis. In this work, the prebiotic potential of two cooked legumes (cowpea and black bean) was investigated in comparison with potato:beef mixture, as substrates in batch faecal culture fermentation. Prior to the fermentation, all the samples were in vitro digested, passing through three phases, namely mouth, gastric and small intestine simulation, and then in vitro fermented for 6, 24 and 48 h. The shift of pH, production of gas and short-chain fatty acids (SCFAs) and changes in gut microbiota were evaluated along the fermentation time. The pH decreased significantly over time in all media with fermentable sources when compared with the negative control. Gas production was higher in the media containing fermentable source than in the negative control and decreased with fermentation time. The concentration of SCFAs increased over time and it was significantly higher for both legumes than in inulin (positive control) and potato:beef meal. Acetate was the major SCFAs produced during fermentation, particularly in media containing legumes. Both legumes presented a strong prebiotic effect on gut microbiota, showing a significant increase in Bifidobacterium and Lactobacillus. These results suggest that consumption of cooked cowpea and black bean, used alone or as an ingredient of novel functional foods, may contribute to improving intestinal health and therefore human health promotion.