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Pastoriza S.,University of Granada | Rufian-Henares J.T.,University of Granada | Morales F.J.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan Csic
LWT - Food Science and Technology | Year: 2012

Coffee and its substitutes have been described as complex matrices for acrylamide (ACR) analysis due to both analytical interferences and ACR instability in the matrix. Melanoidins are multifunctional and biochemically active polymers which are formed in large extent during coffee roasting. Model systems composed of ACR (elimination studies) or glucose-asparagine (ACR formation/elimination studies) with/without melanoidins was heated at 180 °C. Washed sea sand and cellulose microcrystalline were used as matrix. Coffee melanoidins had a direct influence on the fate of ACR under heating, while the effect was not observed at room temperature. In addition, ACR decrease was also related to the reaction time and the initial amount of melanoidins in the media, where clearly a dose-response was observed. In contrast, pH (from 3.5 to 7.0) had no significant effect on ACR reactivity towards melanoidins. It is hypothesized that nucleophilic amino groups of amino acids from the proteinaceous backbone of melanoidins react via the Michael addition reaction with ACR, although the exact mechanism is unknown. Then, melanoidins could modulate the reaction pathways of ACR formation and elimination during coffee roasting and serve as acrylamide-mitigation substance. © 2011 Elsevier Ltd. Source


Dobarganes C.,CSIC - Instituto de la Grasa | Marquez-Ruiz G.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan Csic
British Journal of Nutrition | Year: 2015

The question of whether heated fats in the diet may be detrimental to health is nowadays of the upmost concern, but finding an answer is not easy and requires careful consideration of different aspects of lipid oxidation. This review is divided into two sections. The first part deals with the nature of the new compounds formed at high temperature in the frying process as well as their occurrence in the diet while the second part focuses on their possible nutritional and physiological effects. Oxidation products present in abused frying fats and oils are the compounds most suspected of impairing the nutritional properties of the oils or involving adverse physiological effects. The recent studies on their health implications include those related to their fate and those focused on their effects in metabolic pathways and the most prevalent diseases. Copyright © The Authors 2015. Source


Sanchez-Alonso I.,CSIC - Institute for the Structure of Matter | Carmona P.,CSIC - Institute for the Structure of Matter | Careche M.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan Csic
Food Chemistry | Year: 2012

Vibrational spectroscopy (mid FTIR and FT-Raman) was used to monitor lipids extracted from hake fillets during frozen storage. Kramer shear resistance was used as a marker of texture changes and lipid damage was also investigated by following the development of conjugated dienes and free fatty acids by spectrophotometric methods. Results show that the intensity of the free fatty acid carboxylic ν(CO) band measured by ATR-FTIR spectroscopy can be used for monitoring the development of lipid hydrolysis in hake lipids. Changes in the Raman ν(CC) stretching region (1658 cm -1 band), partially attributed to conjugated dienes development, were the only observed spectroscopic alterations related to lipid oxidation of hake lipids during frozen storage at -10 °C. The high correlation of free fatty acids with instrumental texture and the disappearance of the ν as(PO 2 -) band are consistent with membrane lipid hydrolysis being one of the factors directly related with toughening of lean fish flesh. © 2011 Elsevier Ltd. All rights reserved. Source


Herraiz T.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan Csic | Galisteo J.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan Csic
Biochemical and Biophysical Research Communications | Year: 2014

β-Carbolines are indole alkaloids that occur in plants, foods, and endogenously in mammals and humans, and which exhibit potent biological, psychopharmacological and toxicological activities. They form from naturally-occurring tetrahydro-β-carboline alkaloids arising from tryptophan by still unknown way and mechanism. Results in this research show that heme peroxidases catalyzed the oxidation of tetrahydro-β-carbolines (i.e. 1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid and 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid) into aromatic β-carbolines (i.e. norharman and harman, respectively). This oxidation followed a typical catalytic cycle of peroxidases through redox intermediates I, II, and ferric enzyme. Both, plant peroxidases (horseradish peroxidase, HRP) and mammalian peroxidases (myeloperoxidase, MPO and lactoperoxidase, LPO) catalyzed the oxidation in an efficient manner as determined by kinetic parameters (VMAX and KM). Oxidation of tetrahydro-β-carbolines was inhibited by peroxidase inhibitors such as sodium azide, ascorbic acid, hydroxylamine and excess of H2O 2. The formation of aromatic β-carbolines by heme peroxidases can help to explain the presence and activity of these compounds in biological systems. © 2014 Elsevier Inc. All rights reserved. Source


Sanchez J.A.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan Csic | Ruiz-Capillas C.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan Csic
European Food Research and Technology | Year: 2012

The aim of this study was to optimize the separation of biogenic amines with ion-exchange high-performance liquid chromatography, using the modified simplex method. A modified chromatographic response function was used, and two methodological parameters were selected as simplex variables: the proportion of the organic solvent 2-propanol in the mobile phases, added as a new mobile phase, and the variation of the gradient curve at one specific step in the elution program. In optimum conditions the correct resolution and separation of the biogenic amines (tyramine, β-phenylethylamine, histamine, tryptamine, putrescine, cadaverine, agmatine, spermidine and spermine) were completed in 16 min, reducing the analysis time by 9 min compared with the original method. The regression coefficients were higher than 0. 99 in all the amines, except for spermine (0. 989). The detection limits varied between 0. 06 mg/L, for histamine and agmatine, and 0. 22 mg/L, for tryptamine, while retention time repeatability, determined as a relative standard deviation, was between 4.64% for histamine and 11.95% for tryptamine. The repeatability variation for the amine concentrates was found between 0.71% in cadaverine and 3.23% for tryptamine. Applying the optimized method to samples of refrigerated sardine and sea bream demonstrated the effectiveness of the method in these fish species. © 2011 Springer-Verlag. Source

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