Interlaboratory study on lipid oxidation during accelerated storage trials with rapeseed and sunflower oil analyzed by conjugated dienes as primary oxidation products

11 Páginas.-- 5 Figuras.-- 2 Tablas.-- Material suplementarioAccelerated storage tests are frequently used to assess the oxidative stability of foods and related systems due to its reproducibility. Various methods and experimental conditions are used to measure lipid oxidation. Differences between laboratories make it necessary to determine the repeatability and reproducibility of oxidation tests performed under the same conditions. The objective of the present interlaboratory study was to evaluate the outcome of a storage test for two different bulk oils, sunflower oil (SFO) and rapeseed oil (RSO), during a period of 9 weeks at 20°C, 30°C, 40°C, and 60°C. Sixteen laboratories were provided with bottled oils and conducted the storage tests according to a detailed protocol. Lipid oxidation was monitored by the formation of conjugated dienes (CD) and the activation energy (Ea) was determined for comparative purposes and statistically evaluated. An increase in CD formation was observed for both oils when the storage temperature was increased in all laboratories. The Ea,1 ranged from 47.9 to 73.3 kJ mol−1 in RSO and from 27.8 to 62.6 kJ mol−1 in SFO, with average values of 58.2 and 46.8 kJ mol−1, respectively. The reproducibility coefficients were 10.9% and 18.2% for RSO and SFO, respectively. Practical applications: In order to compare results on oxidative stability of foods derived from different studies, the reproducibility of storage tests and methods employed to evaluate the oxidation level should be considered. This study provides fundamental data on the reproducibility of lipid oxidation under accelerated storage conditions and defines important parameters to be considered for the conduction of experiments.Open access funding enabled and organized by Projekt DEAL. We thank Brökelmann + Co – Oelmühle GmbH + Co for the donation of the vegetable oils. The authors gratefully acknowledge Lina Stuthmann from the Food Technology Division, Kiel University and Inge Holmberg from the National Food Institute, Technical University of Denmark for their skillful help.Peer reviewe

Time-dependent changes in GLT-1 functioning in striatum of hemi-Parkinson rats

Striatal dopamine loss in Parkinson's disease is accompanied by a dysregulation of corticostriatal glutamatergic neurotransmission. Within this study, we investigated striatal expression and activity of the glial high-affinity Na+/K+-dependent glutamate transporters, GLT-1 and GLAST, in the 6-hydroxydopamine hemi-Parkinson rat model at different time points after unilateral 6-hydroxydopamine injection into the medial forebrain bundle. Using semi-quantitative Western blotting and an ex vivo D-[H-3]-aspartate uptake assay, we showed a time-dependent bilateral effect of unilateral 6-hydroxydopamine lesioning on the expression as well as activity of GLT-1. At 3 and 12 weeks post-lesion, striatal GLT-1 function was bilaterally upregulated whereas at 5 weeks there was no change. Even though our data do not allow a straightforward conclusion as for the role of glutamate transporters in the pathogenesis of the disease, they do clearly demonstrate a link between disturbed glutamatergic neurotransmission and glutamate transporter functioning in the striatum of a rat model for Parkinson's disease. (C) 2010 Elsevier Ltd. All rights reserved

Characterization of Seed Oil from Six In Situ Collected Wild <i>Amaranthus</i> Species

Six Amaranthus species (A. cruentus, A. hybridus, A. hypochondriacus, A. muricatus, A. tuberculatus, and A. viridis) were collected in Italy (wild habitats) from crops and roadsides. Amaranth seed oil was extracted to obtain fractions rich in squalene. Squalene, free fatty acid, tocopherol, and sterol composition and content were investigated in detail. An analysis of variance and principal components was performed. The oil content in the seed ranged from 5.17% (A. muricatus) to 12.20% (A. tuberculatus). The quantity of squalene in the oil varied from 3.43% (A. muricatus) to 6.09% (A. hypochondriacus). The primary sterols were beta-sitosterol, brassicasterol, campesterol, and stigmasterol. The main tocopherols in all the samples were alfa-tocopherol, beta-tocopherol, and delta-tocopherol. Our results exhibited that the smallest seeds (A. tuberculatus) have the highest percentages of oil and squalene, whereas the largest seeds size (A. muricatus) show the lowest percentages. There is also evidence that the samples growing at lower altitudes show the highest concentration of fatty acids. According to our results, the six wild Amaranthus species exhibited similar characteristics to commercial species. This study confirms that the site of the collection has an impact on the oil and squalene content of the Amaranthus species

Structured online modules and near-peer teaching in neuroanatomy stimulate active learning and can have beneficial effects on medical students’ scores

Introduction As a solution to a decrease in curriculum time and the continuous growth of student-staff ratio, the Ghent University uses near-peer teaching (NPT) in neuroanatomy practical sessions. To improve learning outcomes, students involved in NPT created an online module. This study evaluated the added value of the online module and investigated tutees' learning experience with NPT. Materials and Methods A cross-sectional study was conducted on second-year medical students who followed a model trajectory. Their completion rate of the online module and results of pre- and posttests on the practical session content, the spotter test, and the theoretical exam were evaluated. Additionally, all second-year medical students were invited to complete a questionnaire on NPT and practical experience. Results A total of 253 second year students were included. Their completion rates of the online module were moderately correlated with the spotter exam results (r = 0.37, p < 0.001). Students who completed all pretests (96.44%) scored significantly better on the spotter exam (p < 0.001). Learners who completed all posttests (50.99%) scored significantly better on the spotter test (p < 0.001). Spotter tests and theoretical exam results were moderately correlated (r = 0.50, p < 0.001). Three-quarters of 352 second year students completed the questionnaire and fully agreed on all statements that assessed NPT and the practical sessions. Conclusion An online neuroanatomy learning module stimulates active learning and can be helpful to improve students' spotter test and neuroanatomy exam scores. NPT is a valuable teaching resource and is generally well perceived in delivering high-quality educatio