Taciana Villela Savian

Efeito de métodos de cocção sobre a composição química e colesterol em peito e coxa de frangos de corte

Neste experimento, objetivou-se comparar os efeitos dos metodos de coccao: cozimento em agua (CA); em oleo (FO); em grelha (GR); em forno convencional (FC) e em forno de microondas (MO), sobre a perda no cozimento (PPC), composicao centesimal (CC), taxas de retencao aparente, taxa de retencao verdadeira da gordura e colesterol dos cortes peito e coxa de frangos. O delineamento experimental foi o inteiramente casualizado, com 5 tratamentos e 5 repeticoes, totalizando 25 parcelas experimentais. Os metodos de coccao influenciaram (P<0,05) a PPC, de forma que files assados no forno de microondas mostraram perdas de 32,49%, maior do que as perdas nos metodos CA, FC, FO e GL (28,40; 27,04; 29,18; e 23,46%, respectivamente). O tratamento FO apresentou, na materia natural, valores mais elevados de gordura no peito (2,49%) e coxa (7,85%), quando comparado aos tratamentos CA, FC, FO, GR, MO (peito, com medias de 1,06 a 1,35 e coxa com medias de 5,06 a 6,27). Os valores de cinzas, na materia seca, demonstraram perda de minerais durante a coccao. Os metodos de coccao sem oleo ocasionam perdas de lipideos das amostras, enquanto os cortes submetidos a fritura absorvem oleo. O corte peito absorve mais gordura do que o corte coxa.

Formação de biofilme em aço inoxidável por Aeromonas hydrophila e Staphylococcus aureus usando leite e diferentes condições de cultivo

The aim of this research was to verify the capability of biofilm formation on stainless steel by Aeromonas hydrophila and Staphylococcus aureus using milk and different conditions of cultivation. The variables consisted in mono and multi-species cultivation of these microorganisms and in the temperatures of 4, 7 and 18 °C. Containers containing 1000 mL of milk, population density of 10 5 CFU.mL –1 of each microorganism, and ten suspended chips of stainless steel AISI 304 (10 × 20 mm) were used to seal up and storage, under 60 rpm of agitation for 10 days. The analyses were conducted every 48 hours. Sessile cells of A. hydrophila and S. aureus and were enumerated by plating in m-Aeromonas selective agar and Baird-Parker agar. Complementary studies included the generation time calculation, enumeration of planktonic cells, and visualization of chips by scanning electron microscopy. S. aureus, in mono-cultivation, formed biofilm at 18 °C and at 7 °C. At 4 °C was observed attachment. The presence of A. hydrophila reduced the performance of S. aureus. In this condition, S. aureus formed biofilm at 18 °C. A. hydrophila formed biofilm under all conditions.

Efeitos dos métodos de abate e sexo na composição centesimal, perfil de ácidos graxos e colesterol da carne de capivaras

The objective of this work was to evaluate the effects of two slaughter methods: traditional (TS) and head-shot (HS) and sex on the proximate composition, fatty acids (FA) profile and cholesterol content of capybara meat. Twenty animals (13 males (M) and 7 females (F)), weighting about 45.71kg, were slaughtered. In longissimus dorsi (LD) muscle were determined: moisture, crude fat, protein and ash. In semimembranosus (SM) muscle, were determined: cholesterol content for colorimetric method and fatty acids (FA) profile for gas chromatography. The LD muscle had values of: 75.87% of moisture, 1.37% of crude fat, 22.11% of crude protein, 1.09% of ash. There were significant differences (p<0.01) between lipid contents of M (1.75%) and F (0.98%). The FA in major concentration (%) were: C16:0 (29.57); C18:1w9 (27.87); C18:2w6 (19.19); C18:0 (6.57); C18:3w3 (4.97); C14:0 (3.64); C20:4w6 (3.45); C18:1w7 (3.31) and C16:1w7 (1.90). Ratio value of poliunsaturated FA to saturated FA was 0.82. The average values of w6 FA and w3 FA were 23.41 and 5.63%, respectively. The factors sex and slaughter method had no effect on poliunsaturated FA percentages and cholesterol content (28.11mg/100g). Capybara meat presented low total lipid content and high crude protein values and FA w6/w3 ratio considered nutritionally adequated.

Composição centesimal e teor de colesterol dos cortes comerciais de capivara (Hydrochaeris hydrochaeris L. 1766)

Com o presente trabalho, objetivou-se determinar a composicao centesimal e o teor de colesterol presente dos diferentes cortes comerciais da carne de capivara. A umidade, proteina, extrato etereo e cinzas foram determinados segundo a AOAC (1990). O colesterol foi determinado por colorimetria. Os cortes comerciais apresentaram media de 75,80% de umidade; 21,74% de proteina; 0,74% de lipidios; 0,90% de cinzas; e 23,3 mg/100g de colesterol. Houve diferenca (P<0,05) nos percentuais de umidade e colesterol entre os cortes comerciais; entretanto, nao houve diferenca sobre os teores de proteina, lipidios e cinzas. Pelos resultados encontrados, verifica-se um baixo teor de lipidios totais e de colesterol, quando comparados com os valores apresentados para carnes de outras especies.

MINERALIZAÇÃO DE NITROGÊNIO EM LATOSSOLOS ADUBADOS COM RESÍDUOS ORGÂNICOS

A taxa de mineralizacao do nitrogenio (N) varia de um residuo orgânico para outro, evidenciando-se dependente da sua composicao quimica e interacao do material orgânico com o solo. Este estudo foi realizado com o objetivo de avaliar a dinâmica de mineralizacao de N de residuos orgânicos incubados em Latossolos. O experimento foi conduzido no periodo de julho de 2007 a abril de 2008, sendo incubadas amostras de estercos, lodos, compostos, substrato e turfa em areia lavada, Latossolo Vermelho-Amarelo (LVA) e Latossolo Vermelho distroferrico (LVdf), com 240 e 670 g kg-1 de argila, respectivamente. O N mineralizado foi avaliado medindo-se os teores de N-NH4+ e N-NO3- em lixiviados coletados aos 15, 30, 45, 60, 75, 90, 120, 150, 180, 210, 240 e 270 dias de incubacao. A mineralizacao de N ocorreu a maiores taxas nos periodos iniciais de incubacao. O N mineralizado (33 a 199,2 mg kg-1) apos 270 dias de incubacao e regulado pelos teores de N total e de carbono soluvel em agua dos residuos orgânicos. Independentemente do meio utilizado para incubacao, os estercos de galinha e de codorna propiciaram os maiores teores de N mineralizado nos Latossolos. A excecao dos estercos de galinha e codorna, ha imobilizacao liquida de N no LVA; mineralizacao liquida de N e verificada no LVdf, para todos os residuos orgânicos. Em relacao as formas de N disponibilizadas pelos residuos, predomina o N-nitrato, sendo a proporcao N-nitrico/N-amoniacal dependente da mistura solo-residuo estudada.

Ajuste dos modelos Gompertz e Logístico aos dados de crescimento de frutos de coqueiro anão verde

The aim of this study was to evaluate the quality fit of nonlinear models, gompertz and logistic data outside diameter, longitudinal (DEL) and transverse (DET) fruits of green dwarf coconut trees, as well as verification of the existence of residual autocorrelation. The results showed that for both, DEL and DET, the logistic model is most appropriate for describing the fruits growth. The fit of the models, for both variables, showed positive residual autocorrelation. For DEL, the residual was modeled by a first order autoregressive process, and for DET, the autoregressive process was considered of second order. Consideration of the autoregressive process resulted in more accurate estimates of the parameters. According to the logistic model, the fruit of the dwarf green, fully developed, have external diameters, longitudinal and transverse, respectively, of 21.56cm and 15.35cm.

A study of in situ degradability: heterogeneity of variances and correlated errors

Degradation models exhibit a non-linear behavior and the selection of a model to describe the degradability depends on the coherence of the model with the involved biological events. The purpose of this study is to evaluate the behavior of the parameters of the degradation model proposed by Mertens & Loften, adjusted to the results of an in situ degradability trial. The experiment evaluated the potential degradable residue of neutral detergent fiber (NDF) of coastcross grass (Cynodon dactylon × Cynodon nlemfuensis) submitted to two cutting ages (30 and 90 days), with three replicates. For each cutting age, the potentially degradable residue of NDF was studied using fifteen incubation times (0; 0,5; 1; 3; 6; 9; 12; 18; 34; 35; 48; 56; 72; 96 e 120 hours). The experimental unit comprised one non-lactating cow with a permanent ruminal fistula. Mean and individual adjustments were obtained for the animals in three different configurations: inverse variance weight without autoregressive errors; unweighted with autoregressive errors, and unweighted without autoregressive errors. Variances of parameter estimators were also obtained by means of the mean parameter covariance matrix, providing expressions for the estimation of the confidence age for the parameters of the model. A weighting of the model by the inverse variance resulted in estimates statistically equal to zero for the colonization time. The use of a structure of second order autoregressive errors improved the fit of the model of Mertens & Loften, providing more precise estimates of the parameters.

Efeito do método de abate e do sexo sobre a qualidade da carne de capivara (Hydrochaeris hydrochaeris)

The aim of this study was to assess the effect of two slaughter methods (SM) and the gender on the quality of capybara meat. The slaughter methods assessed were the humanitarian (HM) and by head-shot (HS). Two lots of 10 animals were used, one of them containing 5 males and 5 females and the other containing 8 males and 2 females. Values of pH of the longissimus dorsi muscle (between the vertebras 10th and 12th) after 1, 3, 5, 7, 9, 11 and 24h post mortem (p. m.), color (L, a e b), weight losses by cooking (WLC) and shear force (SF) were assessed on samples obtained at these points. The results indicated that pH means were not influenced by both SM and sex. The medium values were: 6.24; 6.05; 6.01; 6.01; 6.03; 6.04 and 5.96 at 1, 3, 5, 7, 9, 11 and 24 hours respectively. That demonstrated that in those encourage the installation of the rigor mortis superficial with reduced extension glicolitic. Regarding the color, HS presented higher L* (32.40) values (P<0,05) than HM (29.59), and the effect of gender on this parameter was not observed. On the other color parameters and on WLC no differences among the lots were observed. SF was influenced by SM, with higher values found (P<0,05) for the HS than for the HM, 5.04 and 3.97kgf, respectively.

Parameters estimation in the model for in situ degradability of mertens and loften

Objetiva-se avaliar o comportamento dos parâmetros do modelo de degradacao proposto por Mertens & Loften (1980) ajustado aos resultados de um ensaio de degradabilidade in situ. No experimento e avaliado o residuo potencialmente degradavel da fibra em detergente neutro (FDN) da graminea coastcross (Cynodon dactylon x Cynodon nlemfunensis) cortada aos 60 dias, com tres repeticoes. O residuo potencialmente degradavel da FDN e estudado utilizando quinze tempos de incubacao (0; 0,5; 1; 3; 6; 9; 12; 18; 24; 36; 48; 56; 72; 96 e 120 horas). A parcela experimental e constituida por uma vaca nao lactante, com fistula ruminal permanente. Sao obtidos ajustes medios e individuais para os animais. Obtem-se tambem as variâncias dos estimadores dos parâmetros por meio da matriz de variância e covariância dos parâmetros e pelo metodo jackknife, propondo-se expressoes para a estimacao do intervalo de confianca para os parâmetros do modelo. Os resultados mostram que o metodo de jackknife apresenta maior estimativa de variância para os parâmetros do modelo de Mertens & Loften (1980), resultando em intervalos de confianca de maior amplitude e estimativas dos parâmetros menos precisas, nos ajustes individuais e medios.

Análise bayesiana para modelos de degradabilidade ruminal

The bayesian methodology was used to estimate the parameters of ORSKOV & MCDONALD (1979) and MCDONALD (1981) models. A study was conducted by using both simulated and real data percentage of coastcross grass (Cynodon dactylon x Cynodon nlemfuensis) fiber degradation with neutral detergent fiber degradation over the time. The posterior marginal samples distributions for the parameters were obtained by Gibbs Sampler and Metropolis-Hastings algorithms. The bayesian approach, evaluated and verified by the simulation studied, has proved to be efficient and the parameter estimated were quite close to the parametric values. The parameters estimated for both models using bayesian approach from real data were fairly consistent with the values reported in the literature. The Orskov and McDonald model was more plausible than the description degradation data made by the McDonald model.