Departamento de Ingeniería Química, Ambiental y de los Materiales
URI permanente para esta comunidadhttps://hdl.handle.net/10953/42
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Examinando Departamento de Ingeniería Química, Ambiental y de los Materiales por Autor "Amigo, Lourdes"
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Ítem Monitoring the large scale production of antihypertensive peptides RYLGY and AYFYPEL by HPLC-MS(Springer Nature, 2010-04-01) Contreras-Gámez, María Mar; Gómez-Sala, Beatriz; Martín-Álvarez, Pedro Jesús; Amigo, Lourdes; Ramos-González, Mercedes; Recio, IsidraThis work reports the quantitative analysis of two novel antihypertensive peptides αs1-CN f(90-94), with sequence RYLGY, and αs1-CN f(143-149), with sequence AYFYPEL, by high-performance liquid chromatography–mass spectrometry in food-grade hydrolysates of milk proteins. The method was validated and showed sufficient specificity, reproducibility, linearity and recovery. Linear calibrations of the molecular ions m/z 671.2 and 902.3 were selected for the determination of the peptides RYLGY and AYFYPEL, respectively, and showed good statistical results (R 2 ≥ 0.995 and with no significant lack-of-fit). The simplicity of RP-HPLC-MS method allowed the automated quantification of both antihypertensive peptides without any sample pretreatment. The application of this method permitted the evaluation of some hydrolysis variables, i.e., substrate, temperature, hydrolysis time or enzyme/substrate ratio, on the formation of antihypertensive peptides. The quantitative analysis of RYLGY and AYFYPEL showed that ultrafiltration was not effective to improve the content in active peptides, containing the hydrolysates and their respective permeates similar peptide amounts.Ítem Production of antioxidant hydrolyzates from a whey protein concentrate with thermolysin: Optimization by response surface methodology(Elsevier Ltd., 2011-01) Contreras-Gámez, María Mar; Hernández-Ledesma, Blanca; Amigo, Lourdes; Martín-Álvarez, Pedro Jesús; Recio, IsidraWhey protein concentrate (WPC) enriched in β-lactoglobulin (β-Lg) was hydrolyzed using Corolase PP® and thermolysin to produce hydrolyzates with antioxidant activity. The optimization of the main experimental variables involved in the process, such as type of enzyme, and hydrolysis conditions, concretely enzyme to substrate ratio, time and temperature, were evaluated using response surface methodology. A central composite circumscribed (CCC) design was employed to study the effect of the experimental variables on the antioxidant activity determined by radical scavenging potency. The parameters of the model were estimated by multiple linear regression, and the highest radical scavenging activity (2.57 μmol Trolox/mg protein) was found in WPC hydrolyzed with thermolysin after 8 h at 80 °C and an enzyme/substrate ratio of 0.10 (w/w). Nineteen β-Lg derived peptides were identified by RP-HPLC-MS/MS in this hydrolyzate. Of special interest are peptides LQKW f(58–61) and LDTDYKK f(95–101), which amino acid composition makes them potential contributors on the radical scavenging activity detected.Ítem Stability to gastrointestinal enzymes and structure–activity relationship of β-casein-peptides with antihypertensive properties(Elsevier Inc., 2009-10) Quirós, Ana; Contreras-Gámez, María Mar; Ramos-González, Mercedes; Amigo, Lourdes; Recio, IsidraPhysiological digestion plays a key role in the formation and degradation of angiotensin-converting enzyme (ACE)-inhibitory peptides. In this study, we evaluated the impact of a simulated gastrointestinal digestion on the stability of eight peptides previously identified in fermented milk with antihypertensive activity. Two of these identified peptides with sequences LHLPLP and LVYPFPGPIPNSLPQNIPP, possess ACE-inhibitory activity in vitro and antihypertensive activity in vivo. The results showed that LHLPLP was resistant to digestive enzymes. In contrast, LVYPFPGPIPNSLPQNIPP was totally hydrolyzed and its activity decreased after incubation with pepsin and a pancreatic extract. The peptide LHLPLP was incubated with ACE and was found to be a true inhibitor of the enzyme and to exhibit a competitive inhibitor pattern. A structure–activity relationship study of this peptide was carried out by synthesizing several modified peptides related to the sequence LHLPLP. The substitution of amino acid Leu in the penultimate position by Gly improved the ACE-inhibitory activity twofold and the substitution of Pro at C-terminal position by Arg increased the activity twofold, with an IC50 of LHLPLR as low as 1.8 μM.