Water adsorption isotherms and thermodynamic properties of cassava bagasse, Thermochimica Acta http://dx. HighlightsAdsorption isotherms and composition of cassava bagasse were determined> GAB equation was the best-fitted model to sorption data of type II isotherm> Isosteric heat of sorption was calculated in a range of equilibrium moisture content> Differential enthalpy and entropy confirmed the isokinetic compensation theory> Water adsorption by cassava bagasse is considered an enthalpy driven process> AbstractLosses of food industry are generally wet products that must be dried to posterior use and storage. In order to optimize drying processes, the study of isotherms and thermodynamic properties become essential to understand the water sorption mechanisms of cassava bagasse.For this, cassava bagasse was chemically analyzed and had its adsorption isotherms determined in the range of 293.15 to 353.15 K through the static gravimetric method. The models of GAB, 2 Halsey, Henderson, Oswin and Peleg were fitted, and best adjustments were found for GAB model with R²>0.998 and no pattern distribution of residual plots. Isosteric heat of adsorption and thermodynamic parameters could be determined as a function of moisture content.Compensation theory was confirmed, with linear relationship between enthalpy and entropy and higher values of isokinetic temperature (TB=395.62 K) than harmonic temperature. Water adsorption was considered driven by enthalpy, clarifying the mechanisms of water vapor sorption in cassava bagasse.

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 (R=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·s (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 R=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.

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 (R=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 R=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.

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