Effect of refrigeration storage on the quality of salted and vacuum packaged rainbow trout (Oncorhynchus mykiss) belly flap

4 páginas, 2 figuras.-- Póster presentado al 6th CIGR Section VI International Symposium “Towards a Sustainable Food Chain” Food Process, Bioprocessing and Food Quality Management. Nantes, France - April 18-20, 2011The shelf life of a by-product of the salmon industry was studied. For it, belly flap resulting from rainbow trout (Oncorhynchus mykiss) processing was kept under refrigerated conditions (0-1.5 °C), being its quality changes studied by sensory, physical, chemical and microbiological parameters. The trout were grown in a Chilean farming facility, where belly flap processing (salting and vacuum packaging) was also carried out and finally sent to our laboratory. Quality analyses included seven control points (days 0, 4, 8, 14, 20, 25 and 53) throughout the refrigerated storage; the experiment was carried out in triplicate (n = 3). The microbiological analysis was found decisive to determine the lifetime of the product since after day 53, total plate counts showed to exceed the maximum allowed for this kind of product. Statistically significant (p<0.05) differences were found with storage time for physical parameters such as shear, drip loss and colour. Thus, maximum strength occurred at day 0, falling then sharply at day 4 and maintaining low levels until day 53; drip loss values decreased at day 4, and later on increased until day 53; instrumental L*, a* and b* parameters provided differences throughout the experiment. Proximate composition was unchanged over time, but showed higher levels of lipid contents when compared to other species. With respect to pH, its lowest value was obtained at day 53 and the highest at day 20 (6.11 vs. 6.49, respectively). Sensory evaluation was performed using QDA methodology with trained judges; it showed significant differences for the following parameters: brightness, typical colour, hardness, elasticity, drip, humidity and odour (typical, sour, rancid and putrid); such values showed to satisfactorily correlate with those delivered by physical analysis. The study provides a first approach to the promotion and development of this kind of by-product from the salmon industryThis study is part of the research project of the Domeyko program, financed by the Vicerrectoría de Investigación y Desarrollo de la Universidad de Chile, called: "Evaluación y optimización de los factores que influyen en la inocuidad de alimentos en base a recursos marinos y desarrollo de alimentos funcionales con componentes o subproductos de éstos

The Helicobacter pylori Urease Virulence Factor Is Required for the Induction of Hypoxia-Induced Factor-1α in Gastric Cells

Chronic Helicobacter pylori infection increases the risk of gastric cancer and induction of hypoxia-induced factor (HIF), which is frequently associated with the development and progression of several types of cancer. We recently showed that H. pylori activation of the PI3K-AKT-mTOR pathway in gastric cells increased HIF-1&alpha; expression. Here, we identified the H. pylori virulence factor responsible for HIF-1&alpha; induction. A mutant of the H. pylori 84-183 strain was identified with reduced ability to induce HIF-1&alpha;. Coomassie blue staining of extracts from these bacteria separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed poor expression of urease subunits that correlated with reduced urease activity. This finding was confirmed in the 26695 strain, where urease mutants were unable to induce HIF-1&alpha; expression. Of note, HIF-1&alpha; induction was also observed in the presence of the urease inhibitor acetohydroxamic acid at concentrations (of 20 mM) that abrogated urease activity in bacterial culture supernatants, suggesting that enzymatic activity of the urease is not required for HIF-1&alpha; induction. Finally, the pre-incubation of the human gastric adenocarcinoma cell line AGS with blocking antibodies against Toll-like receptor-2 (TLR2), but not TLR4, prevented HIF-1&alpha; induction. In summary, these results reveal a hitherto unexpected role for the urease protein in HIF-1&alpha; induction via TLR2 activation following H. pylori infection of gastric cells