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Abstract  

The differences in bound water content of beef semimembranous muscle samples obtained from previously chilled (24 h at +4°C) middle-aged beef carcasses were determined by the use of DSC. Initially, samples obtained from fresh, unprocessed meat were frozen at −40, −50 or −65°C to determine their melting peaks for freezable water (free water) content with the use of DSC. The samples were then subjected to an environment with an ambient temperature of −30, −35, −40 or −45°C, with no air circulation, or with an air circulation speed of 2 m s−1, until a thermal core temperature of −18°C was attained; this was followed by thawing the samples until a thermal core temperature of 0°C was reached. This process was followed by subjecting the samples to the ambient temperatures mentioned above, to accomplish complete freezing and thawing of the samples, with DSC, and thereby determination of the freezable water contents, which were then used to determine the peaks of melting. The calculated peak areas were divided by the latent heat of melting for pure water, to determine the freezable water contents of the samples. The percentage freezable water content of each sample was determined by dividing its freezable water content by its total water content; and the bound water content of each sample was determined by subtracting the percentage free water content from the total. In view of the fact that the free water content of a sample is completely in the frozen phase at temperatures of −40°C and below, the calculations of free and bound water contents of the samples were based on the averages of values obtained at three different temperatures.

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Journal of Thermal Analysis and Calorimetry
Authors: J. Monaselidze, Maya Kiladze, D. Tananashvili, Shota Barbakadze, A. Naskidashvili, Anna Khizanishvili, R. Kvavadze, and G. Majagaladze

Abstract  

The heat effects arising at heating of Spirulina platensis cell culture containing different quantity of water (from 98.2 to 10.5 mass% H2O) have been studied. The hydration of Sp. pl. cells determined by the method of microcalorimetry at 25°C (Δn) was equal to 0.32±0.02 g H2O/g of dry biomass. The heat (–Q) evolved by cells in the temperature range 5–52°C decreased exponentially at decrease of mass% H2O and reached zero value at 30.5±3.0 mass% H2O. The total heat of cell denaturation did not change in the range 98.2–40.5 mass% H2O and it sharply dropped at lower values of water.

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bread is bound water [ 7 ]. Methods of bread making can be subdivided into straight dough method and sponge-and-dough method. All ingredients are mixed together in one stage using straight dough method. According to sponge-and-dough method

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Abstract  

The neutron reflection method was applied for the determination of the bound water content and its spread in lateritic mineral. The aim of the work was to study the influence of bound water on the accuracy of the moisture measurement. The distribution of bound water in the mineral can be described by a normal Gaussian curve.

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and the changes of the water properties and tightly and loosely bound water relative content in the bread over storage time. Materials and methods Sample preparation Dough was prepared based on the

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Journal of Thermal Analysis and Calorimetry
Authors: S. Materazzi, G. Maccari, S. De Angelis Curtis, S. Aquili, and P. Ruggieri

Abstract  

Egg-pasta is a very popular food in Italy and its appreciation is growing in Europe and in the United States. In this work, the bound water has been demonstrated to be a quality discriminant parameter to distinguish the low-temperature dried egg-pasta with respect to the high-temperature dried egg-pasta. By the thermoanalytical profiles (TG and DTG), this systematic study scientifically proves the differences induced by the drying process on the egg-pasta samples: the low temperature dried egg-pasta (produced by the ‘Entroterra’ company, brand ‘La Pasta di Camerino’) shows the systematic lower amount of bound water when compared to other brand, high-temperature dried egg-pasta. The difference is constant either before or after the cooking process. Other physical parameters (thickness and width) confirmed the difference.

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Abstract  

Rhyolite-rhyodacite tuff samples were analysed by X-ray powder diffraction, ICP-OES and thermogravimetric (TG) methods to determine mineral and major element composition as well as different types of bound water, respectively. Similarly to CIA values, some TG parameters (H2O[I] — water released up to ca. 200–220°C; H2O[III] — water loss above 500–550°C and H2O[I+III]) show positive correlation to the amount of secondary minerals. Moreover, these parameters are in close positive correlation to CIA values. Our results suggest that TG determination of different types of bound water may serve as a useful tool for estimation and characterisation of alteration degree of rocks.

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Abstract  

Phase transition of water restrained by curdlan suspension annealed at a temperature from 20 to 110°C was investigated by differential scanning calorimetry (DSC). The melting temperature of water restrained by annealed curdlan discontinuously decreased at around 60°C, while the amount of bound water calculated from enthalpy of melting increased at 60°C, regardless of water content. Using a highly sensitive DSC, curdlan suspension with various concentrations was studied. It was found that an endothermic transition was observed at ca. 58°C in a wide range of concentrations. The transition observed at 60°C is thermo-reversible and both temperature and transition enthalpy are constant even after gel formation. Well equilibrated suspension at a temperature lower than 60°C formed no gel.

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Journal of Thermal Analysis and Calorimetry
Authors: G. Mrevlishvili, A. Carvalho, M. Ribeiro da Silva, T. Mdzinarashvili, G. Razmadze, and T. Tarielashvili
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Abstract  

One to three endothermal peaks atributted to melting of bulk and interfacial water were observed by DSC in the regenerated cellulose — water system. The profiles of thermal effects depend on water content, time of conditioning, film pretreatment and the conditions applied during the preceding freezing-thawing cycles. The occurrence might be deduced of melting-crystallisation processes. A large amount of non-freezable strongly bounded water was also detected. Although cellulose absorbs water quickly after immersion, the structural changes consisting on ordering of polymer fraction occur during further conditioning due to increase in strength of water binding. Using the membranes in the separation module at 90C causes weakening of these bonds. Differences between interaction of particular cellulose films with water can be detected during the first, the second and the third heating.

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