Lipid oxidation and colour in pressure‐ and heat‐treated minced chicken thighs

Lipid oxidation and colour in pressurised and heated chicken samples were evaluated. In a preliminary test, raw and overcooked (100 °C/60 min) minced chicken thighs were pressurised (500 MPa/50 °C/30 min). Samples were stored at 4 °C in contact with air. Thiobarbituric acid reactive substances (TBARS) were quantified at 1, 6 and 9 days. Pressure induced oxidation in chicken, but overcooking generated many more secondary oxidation compounds. In a second experiment, raw minced chicken thighs were pressurised (500 MPa/?10, 5, 20 and 50 °C/30 and 60 min) or cooked (90 °C/15 min). Samples were vacuum stored at 4 °C. TBARS were measured at 1 and 9 days, whereas colour parameters (L, a, b and ΔE) were determined at 1 day. No differences in TBARS values were observed between untreated and pressurised samples, whereas cooked samples presented the highest values. Pressurisation for 30 and 60 min generated similar TBARS contents. At 9 days, oxidation values did not increase. Pressurisation and cooking induced marked colour changes. Pressurised samples were lighter and less red than untreated ones. Samples pressurised at 50 °C were the palest and, together with cooked samples, presented the lowest a values. Therefore pressurised chicken thigh cannot be marketed as a fresh product but can be incorporated as an ingredient in ready‐to‐eat meals. Copyright © 2004 Society of Chemical Industry     

Application of an HPLC–MS/MS method for mycotoxin analysis in commercial baby foods

This article describes the validation of an analytical method for the detection of 21 mycotoxins in baby food. The analytical method is based on the simultaneous extraction of selected mycotoxins by matrix solid-phase dispersion (MSPD) followed by liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) using a hybrid triple quadrupole-linear ion trap mass spectrometer (QTRAP®). Information Dependent Acquisition (IDA), an extra confirmation tool for samples that contain the selected mycotoxins, was used. The matrix effects were evaluated, and the corrections for the matrix effects were performed using two calibration approaches: external matrix-matched calibration and internal standard calibration. Matrix-matched calibration was ultimately used for accurate quantification, and the recoveries obtained were generally higher than 70%. The analytical method was applied to the analysis of 35 samples of commercial baby foods. No sample exceeded the maximum limit (ML) fixed by the European Union for these mycotoxins in baby food. However, this survey highlighted the occurrence of mycotoxins in cereal-based infant foods.     

Probing Individual Layers in Functional Oxide Multilayers by Wavelength‐Dependent Raman Scattering

The integration of functional oxides on silicon requires the use of complex heterostructures involving oxides of which the structure and properties strongly depend on the strain state and strain‐mediated interface coupling. The experimental observation of strain‐related effects of the individual components remains challenging. Here, a Raman scattering investigation of complex multilayer BaTiO₃/LaNiO₃/CeO₂/YSZ thin‐film structures on silicon is reported. It is shown that the Raman signature of the multilayers differs significantly for three different laser wavelengths (633, 442, and 325 nm). The results demonstrate that Raman scattering at various wavelengths allows both the identification of the individual layers of functional oxide multilayers and monitoring of their strain state. It is shown that all of the layers are strained with respect to the bulk reference samples, and that strain induces a new crystal structure in the embedded LaNiO₃. Based on this, it is demonstrated that Raman scattering at various wavelengths offers a well‐adapted, non‐destructive probe for the investigation of strain and structure changes, even in complex thin‐film heterostructures.     

Profile of urinary and fecal proanthocyanidin metabolites from common cinnamon (Cinnamomum zeylanicum L.) in rats

Cinnamon (Cinnamomum zeylanicum L.) bark is widely used as a spice and in traditional medicine. Its oligomeric and polymeric proanthocyanidins are believed to be partly responsible for the beneficial properties of the plant. We describe here the metabolic fate of cinnamon proanthocyanidins in the urine and feces of rats fed a suspension of the whole bark. The metabolites include ten mono‐, di‐, and tri‐ conjugated (epi)catechin phase II metabolites and more than 20 small phenolic acids from intestinal microbial fermentation. Some of these are sulfated conjugates. Feces contain intact (epi)catechin and dimers. This suggests that free radical scavenging species are in contact with the intestinal walls for hours after ingestion of cinnamon. The phenolic metabolite profile of cinnamon bark in urine is consistent with a mixture of proanthocyanidins that are depolymerized into their constitutive (epi)catechin units as well as cleaved into smaller phenolic acids during their transit along the intestinal tract, with subsequent absorption and conjugation into bioavailable metabolites.     

Direct injection and determination of the active principles of spices using micellar liquid chromatography

In this work, we develop a simple chromatographic method to identify and determine three active principles: curcumin, capsaicin and piperine. These compounds are present as spices in some plants: turmeric (Curcuma longa), red pepper (Capsicum annuum) and black pepper (Piper nigrum). The method includes a micellar mobile phase containing 0.15 M sodium dodecyl sulphate and 12.5% (v/v) propanol buffered at pH 7, a Kromasil C18 column (125 mm × 4.6 mm, 5 μm particle size) and UV detection set at 210 nm. The micellar liquid chromatography (MLC) method herein reported is simple, sensitive, precise, robust, and samples can be directly injected into the column without any pre-treatment step. Under these conditions, analysis times were below 7 min for the complete resolution of the three compounds. Linearity (r > 0.9998), limits of detection of 0.7, 1.3 and 5 ng/mL and limits of quantification of 2, 4.4 and 15 ng/mL, for capsaicin, curcumin and piperine, respectively, intra- and inter-day precision (RSD, %) less than 5.9, were studied in the method validation. Finally, the MLC method was applied to spiked samples, with recoveries of around 100%, and in nine real samples, and with amounts of spices in the 0.02 and 47.1 mg/g range. The simplicity of the method makes it a good candidate to be used in routine analyses in the area of food control and quality.     

The importance of aneuploidy screening in reciprocal translocation carriers

The purpose of this study is to investigate the aneuploidy rate and the mosaicism of chromosomes not involved in reciprocal translocations. Aneuploidy screening (AS) (13, 16, 18, 21 and 22) was performed as a re-analysis on fixed blastomeres from 126 embryos already analysed in preimplantation genetic diagnosis (PGD) cycles of eight female and five male reciprocal translocation carriers who had not achieved a pregnancy. A successful diagnosis for AS was achieved in 91.3% of embryos; 30.9% were euploid and 60.3% were aneuploid for the five chromosomes analysed. Of the embryos, 8.7% were euploid for AS and normal-balanced for the translocation and 22.2% were euploid for AS but unbalanced for the translocation; 8% of the embryos were aneuploid for AS but normal-balanced for the translocation and 52.4% were aneuploid for AS and also unbalanced for the translocation. At least 58.7% of the embryos were mosaic regarding mosaicism for the chromosomes involved and not involved in the translocations. Six of the 16 embryos transferred in the PGD cycles were aneuploid for the AS study; four of them were also mosaics. AS should be performed in reciprocal translocation carriers after segregation analysis in PGD.     

Comparison of analytical techniques for dynamic trace metal speciation in natural freshwaters

Several techniques for speciation analysis of Cu, Zn, Cd, Pb, and Ni are used in freshwater systems and compared with respect to their performance and to the metal species detected. The analytical techniques comprise the following: (i) diffusion gradients in thin-film gels (DGT); (ii) gel integrated microelectrodes combined to voltammetric in situ profiling system (GIME-VIP); (iii) stripping chronopotentiometry (SCP); (iv) flow-through and hollow fiber permeation liquid membranes (FTPLM and HFPLM); (v) Donnan membrane technique (DMT); (vi) competitive ligand-exchange/stripping voltammetry (CLE-SV). All methods could be used both under hardwater and under softwater conditions, although in some cases problems with detection limits were encountered at the low total concentrations. The detected Cu, Cd, and Pb concentrations decreased in the order DGT > or = GIME-VIP > or = FTPLM > or = HFPLM approximately = DMT (>CLE-SV for Cd), detected Zn decreased as DGT > or = GIME-VIP and Ni as DGT > DMT, in agreement with the known dynamic features of these techniques. Techniques involving in situ measurements (GIME-VIP) or in situ exposure (DGT, DMT, and HFPLM) appear to be appropriate in avoiding artifacts which may occur during sampling and sample handling.     

The Prestige oil spill. 2. Enhanced biodegradation of a heavy fuel oil under field conditions by the use of an oleophilic fertilizer

A field bioremediation assay using the oleophilic fertilizer S200 was carried out 10 months after the Prestige heavy fuel-oil spill on a beach of the Cantabrian coast (North Spain). The field survey showed that S200 significantly enhanced the biodegradation rate, particularly of high molecular weight n-alkanes, alkylcyclohexanes, and benzenes, and alkylated PAHs, paralleling the results previously found in vitro. The most significant molecular bioremediation indicators were the depletion of diasteranes and C-27 sterane components. Enhanced isomeric selectivity was also observed within the C1-phenanthrenes and dibenzothiophenes. Through the analysis of some target aliphatic and aromatic hydrocarbons a number of chemical indicators for assessing the efficiency of field bioremediation as well as identifying the source of highly weathered samples collected in the area after the spill are defined.     

A Novel Mode of Reactivity for Gold(I): The Decarboxylative Activation of (Hetero)Aromatic Carboxylic Acids

Gold(I) salts are found to mediate the decarboxylation of a variety of aromatic and heteroaromatic carboxylic acids at significatively lower temperatures (as low as 60 °C) than the currently used copper(I) (180–190 °C) and silver(I) (80–140 °C) systems. In contrast to silver(I)‐ and copper(I)‐mediated decarboxylations, the resulting aryl‐gold(I) complexes are stable towards protodemetallation and can be readily isolated.