Comparative study of ultrasound application versus mechanical agitation on pork belly brining for bacon production.

Pork belly brining is a time-consuming step of bacon production that needs to be studied and enhanced through suitable technologies. In this sense, this study aimed at evaluating the impact of ultrasound (US), mechanical agitation (AG), and static brine (SB) on the kinetics of water loss (WL), solids gain (SG), and salt content (SC) of pork belly during brining under different temperatures. Mathematical models were used to estimate mass transfer rates, equilibrium parameters, and thermodynamic properties. Peleg model was chosen as the most suitable model to predict the kinetics experimental data (Radj2 ≥ 0.979 and RMSE ≤ 0.014). The increase in the brine temperature increased WL, SG, and SC for all treatments. Nonlinear effects of temperature were observed for WL, SG, and SC, following an Arrhenius-type behavior. The assistance of ultrasound significantly enhanced the velocity of WL, SG, and SC by 32-56%, while AG improved by 18-39% both compared to SB. Brining was considered an endothermic and non-spontaneous process through the thermodynamic assessment. The increase in temperature and the AG and US processes accelerated the formation of the activated complex. The application of ultrasound was considered the most suitable technology to reduce the brining time. However, significant improvements can be obtained by mechanical agitation. Therefore, both methods can be used to reduce the time processing of pork belly aiming at accelerating the bacon production process.

Mass transfer modeling during wet salting of caiman meat (Caiman crocodilus yacare) at different brine temperatures.

Caiman meat is considered exotic and its consumption has significantly increased due to its nutritional quality. This study aimed to evaluate the kinetics of water content (WC) and salt content (SC) at different temperatures (1, 5, 10 and 15 °C) and to evaluate the use of mathematical models to predict the mass transfer kinetics until equilibrium conditions during the wet salting of caiman tail fillets. Moisture and chloride analyses were performed throughout the wet salting process. Four models (Peleg; Weibull; Zugarramurdi and Lupín; Diffusion) were tested to predict WC and SC kinetics in caiman tail fillets subjected to wet salting. The increase in the temperature resulted in a reduction (P < 0.05) in WC and an increase (P < 0.05) in SC. Nonlinear effects on WC and SC kinetics were observed between the different temperatures evaluated. Furthermore, the effective diffusion coefficients (Dw and Ds) increased (P < 0.05) with increasing temperature. Peleg, Weibull, Zugarramurdi and Lupín, and the Diffusion model satisfactorily represented WC and SC rates throughout the process. The kinetic behavior of the parameters of the models corroborated the effects of temperature on those parameters. Peleg was the best model for predicting WC and SC kinetics, and Zugarramurdi and Lupín was the best for predicting the equilibrium conditions of the process (WC∞ SC∞), all parameters which can be used to describe the mass transfer kinetics during wet salting of caiman tail fillets.

Ultrasound-assisted acid hydrolysis of cassava (Manihot esculenta) bagasse: Kinetics, acoustic field and structural effects.

Improving the actual acid hydrolysis of cassava bagasse (CB) with the assistance of high-intensity ultrasound (US) was aimed in comparison with mechanical agitation (AG). The kinetics of reducing and total sugar release were mathematically modeled. The acoustic field characterization and apparent viscosity of the suspensions were correlated. Moreover, microscopic analyses (visible, fluorescence and polarized light) were carried out to identify changes produced by the treatments. Both AG and US-treatments showed themselves to be effective at hydrolyzing CB. However, US-experiments reached equilibrium in the reducing sugar release process earlier and obtained slightly higher values of total sugars released. The Naik model fitted the experimental data with good accuracy. A greater loss in the birefringence of the starch granules and the degradation of lignocellulosic matter was also observed in US-assisted hydrolysis. The actual acoustic power applied was reduced after hydrolysis, probably due to the increase in the apparent viscosity of the resulting suspensions.

Determination of the rheological behavior and thermophysical properties of malbec grape juice concentrates (Vitis vinifera).

The rheological behavior and thermophysical properties (density, specific heat, and thermal conductivity) were experimentally determined as function of temperature (1-66 °C) and solid soluble content (13.6-45.0°Brix) for Malbec grape juice aiming at designing the unit operations involved in beverage industries. Mathematical modeling was performed to provide valuable information about the rheological behavior and thermophysical properties of Malbec grape juice at different concentrations and temperatures. The Ostwald-de Waele model fitted the concentrates rheological behavior with high accuracy. The consistency coefficients were significantly reduced by the temperature increase, following an Arrhenius relationship with activation energy ranging from 11.02 kJ/mol (45.0 °Brix) to 11.54 kJ/mol (21.0 °Brix). In contrast, they were increased by the higher concentration levels, ranging from 0.2044 Pa.sn (13.6 °Brix, 6 °C) to 20.9451 Pa.sn (45.0 °Brix, 1 °C). The flow behavior index was not influenced by temperature; however, it was strictly related to the concentration, assuming shear-thinning behavior (0.96 < n < 0.54), regardless of the solid soluble contents. Density, specific heat, and thermal conductivity were significantly correlated with both the temperature and concentration parameters by second-order polynomial models. The obtained results can be suitable for the potential use of Malbec juice concentrate as a chaptalization agent in winemaking and grape juice production.

Improving sensory acceptance and physicochemical properties by ultrasound application to restructured cooked ham with salt (NaCl) reduction.

The objective of this research was to study the effects of salt reduction and the application of ultrasound (nominal current of 600 W cm-2 for 10 min) on the physicochemical properties, the microstructure and the sensory acceptance of restructured cooked ham. Four treatments with reduced salt including one with the application of ultrasound (1.5, 1.12, 0.75 and 0.75% salt + ultrasound) were produced. The treatment with 0.75% salt provided a reduction of about 30% in the sodium content. The use of ultrasound decreased the Total Fluid Release and increased the hardness. For lightness, the sample with 0.75% salt with the application of ultrasound did not differ from the control at day zero of storage. The use of ultrasound increased redness too. The ultrasound treatment caused micro fissures on the myofibrils. The sensory acceptance of restructured cooked ham with 0.75% of salt was improved with ultrasound applied. The ultrasound showed good potential for use in the production of healthier meat products.

Experimental study of physical and rheological properties of grape juice using different temperatures and concentrations. Part II: Merlot.

The effect of the temperature and concentration on rheological behavior of Merlot juice concentrates was assessed using a rheometer over a wide range of temperature (1-66°C) and concentrations (13.6-45.0Brix) at shear rates of 0.84-212.1 1/s. The Ostwald-De Waele was the best rheological model fitted the data (R2=0.99967 and relative error=7.99%). The consistency levels were significantly reduced with the increase of temperature and increased with the increase of the concentrations, ranging from 0.1766 (13.6Brix at 66°C) to 19.1140Pa·sn (45.0Brix at 1°C). The flow behavior index presented no up or downward pattern when the temperatures were compared. The flow activation energy ranged from 13.95 (45.0Brix) to 24.88KJ/mol (21.0Brix) with a R2=0.9822 and 0.9812, respectively. Density and specific heat were influenced by both temperature and concentration; however, thermal conductivity was only influenced by concentration and temperature in two cases (13.6 and 29.0Brix). The data showed the potential use of Merlot juice concentrates as wine chaptalization agent in winemaking.

Experimental study of physical and rheological properties of grape juice using different temperatures and concentrations. Part I: Cabernet Sauvignon.

The effect of the temperature and concentration on rheological behavior of Cabernet Sauvignon juice concentrates was assessed using a rheometer over a wide range of temperature (1-66°C) and concentrations (13.6-45.0Brix) at shear rates of 0.84-212.1 1/s. The Ostwald-De Waele was the best rheological model fitted the data (R2=0.99957 and relative error=7.77%). The Cabernet Sauvignon juice concentrates presented a non-Newtonian pseudoplastic behavior (n<1). The consistency levels were significantly reduced with the increase of temperature and increased with the increase of the concentrations. The flow activation energy ranged from 28.87 (45.0Brix) to 38.05KJ/mol (37.0Brix) with a R2=0.9798 for both cases. Density and specific heat were influenced by both temperature and concentration; however, thermal conductivity was only influenced by concentration. The Cabernet Sauvignon juice concentrates will be useful as wine chaptalization agent in future studies.

Effect of ethanol, dry extract and reducing sugars on density and viscosity of Brazilian red wines.

BACKGROUND: Density and viscosity are properties that exert great influence on the body of wines. The present work aimed to evaluate the influence of the alcoholic content, dry extract, and reducing sugar content on density and viscosity of commercial dry red wines at different temperatures. The rheological assays were carried out on a controlled stress rheometer, using concentric cylinder geometry at seven temperatures (2, 8, 14, 16, 18, 20 and 26 °C). RESULTS: Wine viscosity decreased with increasing temperature and density was directly related to the wine alcohol content, whereas viscosity was closely linked to the dry extract. Reducing sugars did not influence viscosity or density. Wines produced from Italian grapes were presented as full-bodied with higher values for density and viscosity, which was linked to the higher alcohol content and dry extract, respectively. CONCLUSION: The results highlighted the major effects of certain physicochemical properties on the physical properties of wines, which in turn is important for guiding sensory assessments.

Revisão: propriedades físico-químicas do biodiesel / Physicochemical properties of biodiesel: a review

Esta revisão de literatura teve como objetivo descrever aspropriedades físico-químicas do biodiesel obtido a partir de diferentesmatérias-primas. Foram estudados dados de viscosidade, densidade,número de cetanos, ponto de fulgor, ponto de fluidez, ponto de névoae poder calorífi co de biodiesel obtido de óleo de soja, de coco, farelode arroz, algodão, pequi, babaçu, mamona, palma, dendê, girassol,milho, canola, pinhão manso e karanja. Considerando a diversidadede fontes vegetais e animais que podem gerar biodiesel ressaltasea carência de dados de propriedades físico-químicas para asmatérias-primas ainda inexploradas. Espera-se com este trabalhocontribuir para a criação de banco de dados de propriedades físicoquímicasdo óleo e do biodiesel de diferentes fontes, o que permitiráprojetar e dimensionar tanto os equipamentos necessários à linhade produção quanto motores alternativos.