Publications by authors named "Francisco A Riera"

In order to exploit industrial discards, protein enzymatic hydrolysis is a currently popular methodology for obtaining bioactive peptides. However, once released, most promising peptides have to be selected from the mixture. In this work, the suitability of pepsin (EC 3.

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Today enormous research efforts are being focused on alleviating the massive, adverse effects of obesity. Short peptides are key targets for research as they can be generated from natural proteins, like milk. Here we conducted trypsinogen digestion of beta-lactoglobulin (β-lg), the major mammalian milk protein, to release the hexamer VY6.

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In contrast with other food proteins, such as β-lactoglobulin or caseins, intensely studied for bioactive peptide production, relatively little attention has been paid to serum albumin, the main blood protein, even though blood disposal is a severe problem for meat processors. In this study, serum albumin was hydrolysed with trypsin after several heat treatments and using different enzyme concentrations. The degree of hydrolysis reached and the peptide sequences released over time were evaluated.

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Background: Hyperimmunised bovine milk and whey (whole and defatted) were submitted at 37°C to different pH values (between 1 and 10) and enzymes (pepsin, trypsin and chymotrypsin) at their optimum pH and the IgG immunoactivity against Campylobacter jejuni was measured by means of ELISA assays.

Results: The kinetic antigen-binding capacity (ABC) losses follow a hyperbolic-type equation. The ABC of IgG is strongly reduced at low pH (1 and 2) and the effect is lower at alkaline pH (8 and 10).

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Fourier transform infrared spectroscopy in the attenuated total reflectance mode (ATR-FTIR) combined with partial last square (PLS) algorithms was used to design calibration and prediction models for a wide range of tetrasodium ethylenediaminetetraacetate (Na4EDTA) concentrations (0.1 to 28% w/w) in aqueous solutions. The spectra obtained using air and water as a background medium were tested for the best fit.

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This work studied the behaviour of caseinomacropeptide (CMP) in a whey protein fractionation process based on the selective precipitation of α-lactalbumin (α-la) in an acid medium. Three different acids (hydrochloric, citric and lactic) and different operating conditions (protein concentration, temperature and pH) were considered to perform the precipitation step. Under the optimised precipitation conditions obtained for α-la (pH 4, 55°C, initial α-la concentration around 12 g/l) CMP presents quite similar behaviour to that observed for β-lactoglobulin (β-lg), namely remaining in the supernatant fraction.

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The aim of this work was to study the cleaning of inorganic membranes fouled with whey protein solutions using the enzymatic formulation Alcalase (Novo Nordisk A/S). Hydraulic and chemical methods were considered to characterize the cleanliness of the membranes. Cleaning efficiency was observed to be a function of the operating conditions.

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