Navegando por Autor "Zollner, Ricardo de Lima"

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    Complexation of whey protein with caffeic acid or (−)-epigallocatechin-3- gallate as a strategy to induce oral tolerance to whey allergenic proteins.
    (2019) Pessato, Tássia Batista; Carvalho, Natália Caldeira de; Figueiredo, Daniella de; Colomeu, Talita Cristina; Fernandes, Luis Gustavo Romani; Netto, Flavia Maria; Zollner, Ricardo de Lima
    Proteins and phenolic compounds can interact and form soluble and insoluble complexes. In this study, the complexation of whey protein isolate (WPI) with caffeic acid (CA) or (−)‑epigallocatechin‑3‑gallate (EGCG) is investigated as a strategy to attenuate oral sensitization in C3H/HeJ mice against WPI. Treatment with WPI-CA reduced the levels of IgE, IgG1, IgG2a and mMCP-1 in serum of mice measured by ELISA. This might be related to CD4+LAP+Foxp3+ T and IL-17A+CD4+ T (Th17) cell activation, evidenced by flow cytometry of splenocytes. Treatment with WPI-EGCG, in turn, decreased the levels of IgG2a and mMCP-1 in serum of mice, possibly by the modulation of Th1/Th2 response and the increase of CD4+ Foxp3+ LAP− T and IL-17A+CD4+ T (Th17) cell populations. In conclusion, WPI-CA and WPI-EGCG attenuated oral sensitization in C3H/HeJ mice through different mechanisms. We consider that the complexation of whey proteins with CA and EGCG could be a promising strategy to induce oral tolerance.
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    Physicochemical changes and bitterness of whey protein hydrolysates after transglutaminase cross-linking.
    (2019) Carvalho, Natália Caldeira de; Pessato, Tássia Batista; Negrão, Fernanda; Eberlin, Marcos Nogueira; Behrens, Jorge Herman; Zollner, Ricardo de Lima; Netto, Flavia Maria
    Whey protein hydrolysates are widely used in hypoallergenic formulas. The extensive hydrolysis required to reduce the protein antigenic potential frequently generates bitter-tasting peptides. This study investigates the effect of transglutaminase (TG) catalyzed cross-linking on physicochemical characteristics and bitter taste of whey protein hydrolysates. The chromatographic analysis showed a slight increase in the relative concentration of peptides (p < 0.05) with molecular mass of 1.4–3.5 kDa (SEC-HPLC) and changes in peak intensity and peptide hydrophilicity after TG-treatment (RP-HPLC). The MALDI-MS peptide fingerprinting presented changes in relative intensities and suppression of signals after TG-treatment, suggesting that cross-linking occurred, mainly in the m/z 1600–3000 range peptides. Changes in the spatial conformation of peptides after TG-treatment were evidenced by the intrinsic fluorescence of the samples. Despite the changes in the physicochemical characteristics of peptides, no differences (p > 0.05) in the intensity (6–7, on a scale up to 9) and duration (38 s) of the bitterness sensation were observed. Possibly, the presence of free glutamine and the significant amount of short peptides with no glutamine or lysine residue may have decreased the opportunities for cross-linking formation; therefore, the presence of bitter-tasting peptides was unchanged as a consequence of TG-treatment.