Study of the effect of ozone in aqueous solution and chemical agents on strawberry’s safety (fragaria anannassa)

[PORT] O desenvolvimento de tecnologias inovadoras que promovam a segurança de frutos e vegetais, reduzindo o risco de doenças associadas a produtos contaminados, constitui uma preocupação actual. Os tratamentos térmicos, quando convenientemente aplicados, são eficientes na redução da carga microbiana dos frutos e vegetais. Contudo, a temperatura tem um impacto bastante negativo ao nível da textura dos alimentos. Como alternativa podem ser utilizados diversos agentes químicos na lavagem dos hortofrutícolas, tais como soluções de peróxido de hidrogénio e de cloro, de forma a garantir a sua segurança e maior retenção de qualidade. Mais recentemente, a utilização de ozono como agente desinfectante, quer em fase aquosa, quer em fase gasosa, tem vindo a ser objecto de estudo. Com este trabalho pretendeu-se estudar o efeito do ozono em solução aquosa, na redução de mesófilos totais em morango. Os resultados foram comparados com os obtidos por lavagens utilizando dois agentes químicos: soluções de peróxido de hidrogénio (1% e 5% m/m) e soluções de hipoclorito de sódio disponível na forma comercial de Amukina (11.5 g/L). Todos os tratamentos aplicados tiveram a duração de 2 minutos. Os tratamentos com ozono foram combinados com tratamentos térmicos (branqueamentos a 50 ou 55 ºC, durante 1 minuto). Os resultados mostraram que o tratamento não térmico mais eficaz na redução da flora mesófila, foi a lavagem com peróxido de hidrogénio a 5% (redução de cerca de 2 ciclos logarítmicos). Estes resultados não são significativamente diferentes dos resultados obtidos com lavagens com água ozonada (resultados confirmados por ANOVA e testes Post Hoc). O efeito dos tratamentos térmicos, a 50 e 55 ºC, não foi potenciado quando estes foram combinados com lavagens com ozono. Resultados semelhantes foram obtidos quando os tratamentos combinados foram aplicados por ordem alternada (i.e. branqueamento vs ozono ou ozono vs branqueamento). [ENG] The development of innovative technologies, aiming at reducing the risk of related food-borne diseases and thus promoting fruits and vegetables, is an actual concern. Thermal treatments, when conveniently applied, are efficient in microbial load reduction. However, temperature has a negative impact at food textural level. Alternatively, washings with solutions of several chemical agents, such as hydrogen peroxide or sodium hypochlorite, may be applied. More recently, the use of ozone as a disinfectant agent, both in aqueous or in gaseous phases, has been considered. The objective of this work was to study the effect of ozone in aqueous solution, on total mesophyles reduction in strawberries. Results were compared to the ones obtained with washings with two chemical agents: hydrogen peroxide solutions (1% and 5% w/w) and sodium hypochlorite solutions, commercially available as Amukina (11.5 g/L). All treatments were applied for 2 minutes. Ozone treatments were also combined with thermal processes (blanching at 50 or 55 ºC, for 1 minute). Results showed that washings with hydrogen peroxide solutions at 5% were the most efficient non-thermal treatments applied for mesophyles reduction in strawberries (approximately 2 log-cycles). These results were not significantly different from the ones obtained with ozonated-water washings (confirmed by ANOVA and Post Hoc tests). The thermal treatment effect, at 50 and 55 ºC, was not enhanced when combined with ozonatedwater washings. Similar results were obtained when the combined treatments were applied by alternated order (i.e. blanching vs ozono ou ozono vs blanching).Os autores agradecem o apoio financeiro ao Programa Operacional Agricultura e Desenvolvimento Rural – Projecto AGRO nº822 (Novas Tecnologias de Processamento de Hortofrutículas Congelados – EMERCON). Os autores Alexandre E.M.C., Santos-Pedro D.M. e Brandão T.R.S. agradecem ainda à Fundação para a Ciência e a Tecnologia (bolsas de investigação SFRH/BD/16042/2004, SFRH/BPD/9174/2002 e SFRH/BPD/11580/2002, respectivamente)

Satietogenic Protein from Tamarind Seeds Decreases Food Intake, Leptin Plasma and CCK-1r Gene Expression in Obese Wistar Rats

Objective: This study evaluated the effect of a protein, the isolated Trypsin Inhibitor (TTI) from Tamarindus indica L. seed, as a CCK secretagogue and its action upon food intake and leptin in obese Wistar rats. Methods: Three groups of obese rats were fed 10 days one of the following diets: Standard diet (Labina®) + water; High Glycemic Index and Load (HGLI) diet + water or HGLI diet + TTI. Lean animals were fed the standard diet for the 10 days. Food intake, zoometric measurements, plasma CCK, plasma leptin, relative mRNA expression of intestinal CCK-related genes, and expression of the ob gene in subcutaneous adipose tissue were assessed. Results: TTI decreased food intake but did not increase plasma CCK in obese animals. On the other hand, TTI treatment decreased CCK-1R gene expression in obese animals compared with the obese group with no treatment (p = 0.027). Obese animals treated with TTI presented lower plasma leptin than the non-treated obese animals. Conclusion: We suggest that TTI by decreasing plasma leptin may improve CCK action, regardless of its increase in plasma from obese rats, since food intake was lowest

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters