Modelling autocatalytic behaviour of a food model system- sucrose thermal degradation at high concentrations

Sucrose thermal degradation is an important reaction in the food industry. When in concentrated and neutral solutions, pure sucrose presents a lag phase in the reaction. This work aimed at: (i) modelling sucrose thermal degradation autocatalytic behaviour and (ii) studying the concentration and temperature effects on kinetic parameters. Isothermal experiments were conducted at temperatures ranging from 100 to 180 C, using solutions with varying water content (3.58–30.03 (% w/w)). The logistic and Gompertz sigmoidal equations were modified and reparameterised, in order to describe degradation behaviour with kinetic parameters with physical meaning (maximum reaction rate, kmax, and lag time, k). In both models these parameters presented an Arrhenius type dependence on temperature. Following a mixed model effect methodology, the concentration dependence was observed on the Arrhenius parameters. This concentration effect was included in the proposed kinetic models, which were able to successfully describe experimental data

As Borboletas (lepidoptera: Papilionoidea E Hesperioidea) Da Reserva Particular Do Patrimônio Natural Fazenda Lontra/saudade, Itanagra, Litoral Norte Da Bahia, Brasil

The Private Reserve of Natural Heritage Fazenda Lontra/Saudade (FLS), located in the Northern Coast of Bahia state, Brazil, is the largest (1,377.33 ha) preserved Atlantic Forest area between Paraguaçu and São Francisco rivers in Bahia and Sergipe, respectively. A list of 260 species belonging to six families of butterflies is presented herein, being recorded 4 species of Papilionidae, 16 of Pieridae, 29 of Lycaenidae, 41 of Riodinidae, 87 of Nymphalidae and 83 of Hesperiidae. The butterfly community was composed mainly by widespread species commonly found in open habitats. There were also many species typical of forested areas, as such Morpho telemachus richardusFruhstorfer, 1898 (Nymphalidae: Morphini), a new record to the Northeastern Brazil. © 2016, Universidade Estadual de Campinas UNICAMP. All rights reserved.16

A modified gompertz model to predict microbial inactivation under time-varying temperature conditions

Development of effective heat treatments is crucial to achieve food products safety, and predictive microbiology is an excellent tool to design adequate processing conditions. This work focuses on the application of a modified Gompertz model to describe the inactivation behaviour under time-varying temperature conditions at the surface of a food product. Kinetic studies were carried out assuming two different heating regimes, typically used in surface pasteurisation treatments, and compared with isothermal conditions. Parameters were estimated on the basis of generated pseudo-experimental data. It was concluded that the heating period greatly affects microbial inactivation and parameter estimation. If a slow heating treatment is used, the process time should be extended to achieve a given microbial load when compared to a fast heating process. This is explained by the fact that, in the slow heating rate process the temperature was below the lowest temperature for inactivation for a much longer time, in comparison with the fast heating regime. 2005 Elsevier Ltd. All rights reserved

Effect of broiler breast abnormality and freezing on meat quality and metabolites assessed by 1H-NMR spectroscopy

ABSTRACT The present study aimed at investigating the impact of the current growth-related abnormalities (White-Striping—WS, Wooden Breast—WB, and Spaghetti Meat—SM) affecting broilers Pectoralis major muscles on the main quality traits, the oxidative stability of both the lipid and protein fraction as well as the water mobility assessed in fresh and frozen/thawed meat. In addition, Nuclear Magnetic Resonance spectroscopy (1 H-NMR) was applied to quantify free amino acids, histidine-containing dipeptides and metabolites involved in energy-generating pathways. Overall, the occurrence of WS, WB, and SM abnormalities remarkably affected the quality traits (pH, color, and water holding capacity) and oxidative stability of the meat, with the WB condition leading to the most detrimental effects. However, overall, freezing and subsequent thawing only partially worsened the aforementioned traits. Significant variations in free amino acids and histidine-containing dipeptides were found between abnormal muscles and their unaffected counterpart by 1 H-NMR spectroscopy and, aside from the occurrence of muscular defects, their content was remarkably reduced in frozen/thawed meat. The findings obtained by analyzing the metabolites through 1 H-NMR spectroscopy allowed to advance the knowledge concerning the impact of freezing and subsequent thawing on meat quality traits and provided useful information concerning the underlying mechanisms responsible for the development of WS, WB, and SM abnormalities in broilers

Quantification of microstructural changes during first stage air drying of grape tissue

Microstructural changes in cells of Ruby grape (Vitis vinifera) quarters were monitored during first stage of convective air drying, under a stereo-microscope. A gradual overall shrinkage of grape cells was observed during the process. The cellular parameters: area, perimeter, major and minor axis length, Feret diameter, elongation, roundness and compactness, were quantified by image analysis. It was verified that cell dimensions suffered modifications during drying, but their shape remained unchanged. These microstructural changes showed a smooth exponential decrease with time, and a first-order kinetic model was satisfactorily fitted to the data. Temperature increased the rate of cellular shrinkage and this effect followed an Arrhenius type behaviour. Increasing temperature from 20 to 60 C resulted in a 350% increase of the area change rate. For the parameters related to cellular dimensions, the magnitude of the values were 10 3 min 1 for the rate of change at 40 C and 3 kJ/mol for the activation energ

Striatal and extrastriatal atrophy in Huntington's disease and its relationship with length of the CAG repeat

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that affects the striatum most severely. However, except for juvenile forms, relative preservation of the cerebellum has been reported. The objective of the present study was to perform MRI measurements of caudate, putamen, cerebral, and cerebellar volumes and correlate these findings with the length of the CAG repeat and clinical parameters. We evaluated 50 consecutive patients with HD using MRI volumetric measurements and compared them to normal controls. Age at onset of the disease ranged from 4 to 73 years (mean: 43.1 years). The length of the CAG repeat ranged from 40 to 69 (mean: 47.2 CAG). HD patients presented marked atrophy of the caudate and putamen, as well as reduced cerebellar and cerebral volumes. There was a significant correlation between age at onset of HD and length of the CAG repeat, as well as clinical disability and age at onset. The degree of basal ganglia atrophy correlated with the length of the CAG repeat. There was no correlation between cerebellar or cerebral volume and length of the CAG repeat. However, there was a tendency to a positive correlation between duration of disease and cerebellar atrophy. While there was a negative correlation of length of the CAG repeat with age at disease onset and with striatal degeneration, its influence on extrastriatal atrophy, including the cerebellum, was not clear. Extrastriatal atrophy occurs later in HD and may be related to disease duration.1129113

Modelling the kinetics of peroxidase inactivation, colour and texture changes of pumpkin (Cucurbita maxima L.) during blanching

The effects of blanching treatment on peroxidase inactivation, colour and texture of pumpkin (Cucurbita maxima L.) were studied in the temperature range of 75–95 C. Peroxidase inactivation followed a first-order Arrhenius model, where the activation energy and rate of the reaction at a reference temperature of 85 C were 86.20 ± 5.57 kJ mol 1 and 0.27 ± 0.01 min 1, respectively. During blanching, pumpkin became darker and softer with processing time. The degradation of colour (evaluated throughout CIE L*a*b* colour system, with chroma index and total colour difference) and texture parameters (firmness and energy) showed a fractional conversion model kinetics, being the temperature effect on kinetic parameters well described by the Arrhenius law. The results of this work are a good tool to further optimise pumpkin blanching conditions

Distribuição das Diatomáceas Modernas nos Sedimentos da Baía de Guanabara e Áreas Oceânicas, Rio de Janeiro (Brasil)

One hundred and fifty three superficial sediments were collected in Guanabara Bay to physical-chemistry and diatom analyses in the ambit to Monitoring Project (CENPES/PETROBRAS). A total of 146 taxa of diatoms were identified where the most frequent taxa in Guanabara Bay were Amphora spp., Coscinodiscus spp. and Navicula yarrensis var. yarrensis. These species are potentially harmful that might harm fisheries and mariculture during blooms. The values of ecological indexes like richness and diversity followed the estuarine gradient were the higher values were found in the mouth and de low in the inner part. The multivariate analyzes permitted recognize seven diatom assemblages in the bay. The DCA analyze shows the most influence in the distribution of assemblages were the depth and pH. The diatom assemblages analyze proved to be an efficient tool in the environmental diagnosis of Guanabara Bay.Cento e ciquenta e três amostras de sedimento superficial da Baía de Guanabara foram coletadas durante o Projeto de Monitoramento Ambiental (CENPES/PETROBRAS). Foram identificados 146 táxons de diatomáceas onde as espécies mais abundantes foram Amphora spp., Coscinodiscus spp. e Navicula yarrensis var. yarrensis. Estas espécies identificadas são potencialmente tóxicas e podem prejudicar peixes e a maricultura durante períodos de florescência. Os índices ecológicos de riqueza e diversidade acompanharam o gradiente estuarino sendo maior na entrada da baía e baixos na região interna. As análises multivariadas permitiram reconhecer sete assembléias de diatomáceas na baía. As análises em DCA mostrou que os parâmetros ambientais mais influentes na distribuição das assembléias foram a profundidade e o pH. Os resultados obtidos mostraram que as assembléias de diatomáceas são uma importante ferramenta na caracterização ambiental da Baía de Guanabara

Thermosonication applied to kiwi juice processing: anti-listerial effect and quality retention

info:eu-repo/semantics/acceptedVersio