Percorrer por autor "Santoyo, Susana"
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- Polyphenol bioaccessibility, caco-2 cell uptake and prebiotic potential of walnut oil industry by-products following simulated digestionPublication . Spréa, Rafael Mascoloti; Rodrigues, Daniele Bobrowski; Calhelha, Ricardo; Pires, Tânia; Brassesco, María; Pintado, Manuela; Santoyo, Susana; Arranz, Elena; Prieto, Miguel; Barros, Lillian; Amaral, JoanaThe valorisation of agri-food by-products represents a sustainable strategy for the development of functional ingredients. Walnut oilcake (WOC) and walnut oil dregs (WOD), respectively obtained after cold-press extraction and from the decantation residues of the oil following cold pressing, were evaluated for their nutritional composition, phenolic profile, and in vitro bioaccessibility and bioavailability. The standardized INFOGEST 2.0 protocol was applied to simulate human gastrointestinal digestion, enabling the separation of bioaccessible and non-bioaccessible fractions. Phenolic compounds were quantified by HPLC-DAD-ESI/MS, revealing glansreginin A and ellagic acid as major constituents. After digestion, WOD displayed significantly higher total polyphenol bioaccessibility (78%) compared to WOC (15%). Ellagic acid presented the highest bioaccessibility in both matrices (>100%), while dicarboxylic acid derivative showed limited release. Antioxidant assays demonstrated a marked improvement in activity after in vitro digestion, with EC? ? values decreasing from 4.2 ± 0.6 to 2.6 ± 0.8 mg/mL (TBARS) and from 2.5 ± 0.2 to 0.4 ± 0.1 mg/mL (DPPH) for WOD, and from 2.6 ± 0.2 to 0.4 ± 0.1 mg/mL (TBARS) and from 0.9 ± 0.1 to 0.4 ± 0.1 mg/mL (DPPH) for WOC, indicating enhanced compound release during in vitro digestion. Caco-2 cell transport assays were used to evaluate intestinal absorption. Glansreginin A, a dicarboxylic acid derivative, was detected only in the apical compartment, with no phenolics found in the basolateral fraction, indicating limited trans-epithelial transport and suggesting that the health benefits of these compounds may be mediated by colonic metabolism rather than direct absorption. The non-bioaccessible fractions showed strong prebiotic activity, stimulating the growth of three Lactobacillus and one Bifidobacterium strains, surpassing, in some cases, the positive control fructooligosaccharides. These findings highlight the relevance of combining in vitro digestion and cell culture models to assess the fate of polyphenols from food by-products. This study supports the potential of WOC and WOD as sources of bioactive and prebiotic compounds, reinforcing their application in functional foods and sustainable food systems.
- Supercritical fluid extraction of polyphenols from almond oil industry by-products: evaluating bioaccessibility and bioavailability through in vitro digestionPublication . Spréa, Rafael Mascoloti; Rodrigues, Daniele B.; Brassesco, María E.; Pintado, Manuela; Santoyo, Susana; Arranz, Elena; Prieto, Miguel A.; Amaral, Joana S.; Barros, LillianSupercritical fluid extraction (SFE) has emerged as an advanced green technology for the recovery of bioactive compounds, offering enhanced extraction efficiency while eliminating the need for toxic organic solvents. In this context, industrial residues from almond oil production were subjected to CO? SFE by ISANATUR (Navarra, Spain), a company specializing in by- product valorization. Specifically, almond press cake (APBF+) from cold press extraction was submitted to SFE using 20 MPa and 24 MPa for further oil extraction, yielding two additional by- products (APBF20 and APBF24, respectively). Given the potential application of these by-products (APBF+, APBF20 and APBF24) in functional food formulations and nutraceuticals, this study aimed to assess and compare the bioaccessibility of polyphenols following in vitro gastrointestinal digestion. The samples were digested using the standardized INFOGEST 2.0 static protocol. Polyphenolic compounds and their bioaccessible fraction (post-dialysis) were characterized by HPLC-DAD-ESI-MS. Additionally, both non-digested and digested samples were evaluated for their antioxidant capacity using DPPH and TBARS assays. The prebiotic potential of the non-bioaccessible fraction was assessed in vitro using three Lactobacillus and one Bifidobacterium strains. Finally, the bioaccessible fraction was subjected to Caco-2 cell transport assays to evaluate intestinal permeability. A total of 22 polyphenols were identified in all almond by-products with the SFE-treated samples exhibiting only around 10% loss of polyphenols. After digestion, an average of 64% of total polyphenols in APBF+ remained bioaccessible. Notably, SFE-treated samples exhibited enhanced polyphenol bioaccessibility, reaching 73% and 72% for APBF20 and APBF24, respectively. Interestingly, the digested extracts exhibited a reduction in EC?? values in both antioxidant assays, indicating enhanced antioxidant capacity after in vitro digestion. Both non- digested and digested samples showed prebiotic activity, yielding higher optical density values compared to the positive control (fructooligosaccharides), which suggests that the digested almond by-products can promote gut health. This work shows that SFE by-products retain a high content of polyphenols, with high bioaccessibility and antioxidant activity after in vitro digestion, thus reinforcing the potential of almond by-products as sustainable sources of functional ingredients for the food and nutraceutical industries.