Percorrer por autor "Amaral, Joana S."
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- Potential of walnut (Juglans regia L.) oil by-products as functional food ingredients: antioxidant and prebiotic properties post the simulated gastro-intestinal tract digestionPublication . Spréa, Rafael Mascoloti; Cardoso, Rossana V. C.; Brassesco, María E.; Pintado, Manuela; Prieto, Miguel A.; Barros, Lillian; Amaral, Joana S.The oilcake and oil decantation dregs are primary by-products of the walnut oil industry, currently being repurposed as fertilizers or animal feed1. This study explores their potential application as food ingredients by assessing their bioactivity, specifically antioxidant and prebiotic properties, both pre- and post-simulated gastrointestinal tract (GIT) digestion according to the INFOGEST protocol. Antioxidant activity was evaluated using two in vitro assays: inhibition of lipid peroxidation measured by thiobarbituric acid reactive substances (TBARS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging. The prebiotic potential of the samples at a 2% concentration was tested with five probiotic strains. When comparing the EC50 values of the bioaccessible fractions (BF) obtained post-GIT, both the digested oilcake and dregs exhibited enhanced antioxidant activity (an increase of 86% and 84% for the oilcake and 38% and 55% for dregs, in TBARS and DPPH, respectively) compared to the corresponding initial samples. Furthermore, the by-products BF stimulated probiotics growth, surpassing the positive control (fructooligosaccharides) and the samples not subjected to GIT, which underscores the potential of these by-products for gut health. Overall, the bioactivity of the studied by-products was even improved by digestion, which highlights their suitability as functional foods.
- 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.