Publications by authors named "Valeria Tironi"

This study focused on studying the bioaccesible phenolic compounds (PCs) from yellow pea flour (F) and protein isolate (I). Total phenolic contents (TPC), PCs composition and antioxidant activities were analysed in ethanol 60% extracts obtained by applying ultrasound assisted extraction (UAE, 15 min/40% amplitude). The preparation of I under alkaline conditions and the elimination of some soluble components at lower pH produced a change of PCs profile and antioxidant activity.

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This study focused on evaluating the potential of the natural fermentation of pea flour to improve the release of antioxidant compounds. Preliminary fermentations of 36.4% / flour dispersions were performed in tubes under different conditions (24 and 48 h, 30 and 37 °C).

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This study evaluated the incorporation of two ingredients as a source of bioactive compounds: amaranth flour (AF) and grape pomace peels flour (GP) to improve the nutritional qualities and functional properties of a wheat bread, emphasising the revalorisation of agricultural residues from grape winemaking as an ethical and economically viable source of bioactive compounds. Specifically, wheat flour (WF) substitutions were carried out for the individual ingredients, replacing 20% WF (A20 bread) or 5% GP (GP5 bread) and a mixture of both ingredients 20% WF and 5% GP (A20GP5 bread), and the antioxidant potential of the breads was analysed. The effect of simulated gastrointestinal digestion (SGID) on the phenolic profile and antioxidant activity of the fortified breads was also investigated.

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The potential of peptides generated by simulated gastrointestinal digestion (SGID) of two products derived from Amaranthus manteggazianus seeds, flour (F) and beverage (B), to exert peroxyl scavenging activity (ORAC) and antioxidant action on intestinal cells was studied. B was prepared by solubilisation of seed proteins, with the addition of gums and the application of a pasteurization treatment. The gastrointestinal digests FD and BD showed some differences in the peptide/polypeptide composition.

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The relationship between structural and physicochemical properties and antioxidant activity of peptides from amaranth 11S-globulin was studied. Peptides AWEEREQGSR, TEVWDSNEQ, IYIEQGNGITGM and YLAGKPQQEH had the greatest activity (ORAC, HORAC). GDRFQDQHQ, HVIKPPSRA and KFNRPETT were the most active ones against Cu/HO-induced-LDL oxidation.

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Whey is an abundantand sustainable source of bioactive peptides obtained from cheese making process. Whey proteins such as α-lactalbumin can be biologically active when the bioactive peptides encrypted in the amino acid sequence of the native protein are released by enzymatic hydrolysis. In the present work, the identification, sequence analysis, and antioxidant activity of bioaccessible peptides from α-lactalbumin alcalase-hydrolysate was assessed.

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The effect of both the simulated gastrointestinal digestion conditions and the matrix over protein hydrolysis and antioxidant peptides generation was evaluated by comparing an in-house method with COST INFOGEST-based SGD protocols. The in-house protocol was used to digest amaranth protein isolate I (Id1), while the standardized method and a modified version (similar enzyme/substrate ratio than in our lab) were used to digest I and amaranth flour F (Id3 and Fd3, Id2 and Fd2). Protein hydrolysis degree (TNBS method) was similar for the three I digested (about 60%), but lower for F digested (45 and 34% for Fd2 and Fd3, respectively).

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In this work, there were analysed the interaction between phenolics present in amaranth flour (F) and amaranth protein isolate (I) with other components, as well as the effect of the gastrointestinal digestion on them (Fd and Id). Extractions were performed under different conditions (temperature, acid, organic solvent, alkali). Methanol/water extracts (25 °C and 80 °C) from F showed the presence of isoquercetin/rutin, quercetin, kaempferol and two unidentified peaks (II and III).

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This study evaluated the effect on Wistar rat's oxidative status of incorporating amaranth flour (AF) and protein isolate (AI) in increased-fat diets. Five of the groups were fed for 4 weeks with either BD (basal diet), Chol+F (2% cholesterol, 10% porcine fat), Chol+F+E (0.005% α-tocopherol), Chol+F+AF or Chol+F+AI (25% of protein replacement) diets.

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Article Synopsis
  • The study aimed to separate and identify antioxidant peptides from Amaranthus mantegazzianus proteins, focusing on a simulated gastrointestinal digest.
  • Preparative RP-HPLC was used to isolate fractions, which were then assessed for antioxidant activity using the ORAC method, with promising fractions analyzed via LC-MS/MS.
  • Among the synthesized peptides based on the 11S globulin, four showed significant antioxidant activity, containing structural features typical of known antioxidant peptides, particularly with bulky aromatic residues.
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The effects of the dietary addition of 2.5% (w/w) Amaranthus mantegazzianus protein isolate (AI) on blood pressure, lipid profiles and antioxidative status of Wistar rats were evaluated. Six diets were used to feed animals during 28 days: (base (AIN93G), Chol (cholesterol 1%, w/w), CE (α-tocopherol 0.

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We evaluated the capacity of simulated gastrointestinal digests or alcalase hydrolysates of protein isolates from amaranth to scavenge diverse physiologically relevant reactive species. The more active hydrolysate was obtained with the former method. Moreover, a prior alcalase treatment of the isolate followed by the same simulated gastrointestinal digestion did not improve the antioxidant capacity in any of the assays performed and even produced a negative effect under some conditions.

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