Thermal properties of semolina doughs with different relative amount of ingredients

The impact of the relative amount of ingredients, wheat variety, and kneading time on the thermal properties of semolina doughs were investigated by means of thermogravimetric analysis (TGA). The doughs were prepared by mixing water, semolina, yeast, and salt in different proportions. The gelatinized flour fraction plays an important role in the thermal properties' definition, while the water amount influences the development of the dough network and, consequently, the starch gelatinization phenomena. Furthermore, the amount of yeast and salt influences the dough network force and, consequently, the thermal properties. The TGA technique was applied in order to evidence the mass loss as a function of the increasing temperature, considering that this behavior depends on the dough network force and extension. In such a way, it was possible to find some information on the relationship between the dough characteristics and the thermogravimetric analysis outputs. The study is devoted to acquiring deeper knowledge about the thermophysical characteristics of doughs in the breadmaking industrial processes, where the controllability and the energy performances need to be improved. A deeper knowledge of the dough properties, in terms of measurable parameters, could help to decrease the amounts of off-specification products, resulting in a much more energy-efficient and sustainable processing

Microwave heating improvement: permittivity characterization of water–ethanol and water–NaCl binary mixtures

Microwave heating offers a lot of advantages compared to conventional heating methods in the chemical reactions field due to its positive effects on reaction time and selectivity. Dielectric properties, and in particular permittivity, of substances and mixtures, are important for the optimization of microwave heating processes; notwithstanding this, specific databases are poor and far from being complete, and in the scientific literature very little data regarding these properties can be found. In this work, impedance measurements were carried out using a specially designed system to get the real and imaginary parts of the dielectric constant. The apparatus was tested in the estimation of permittivity of water–ethanol and water–NaCl mixtures, varying their composition to obtain a wide range of permittivity values. The results were compared to literature data and fitted with available literature models to verify the correspondence between them, finding that permittivity dependence on mixture composition can be effectively described by the models

The effect of the relative amount of ingredients on the rheological properties of semolina doughs

"Pani carasau" is a traditional Sardinian bread, made with re-milled durum wheat semolina, with a long shelf-life. The production process is highly energy consuming, but its automation can make it more energy-efficient and sustainable. This requires a deep knowledge of the rheological parameters of the doughs. This study investigated the rheological properties of doughs-prepared by mixing semolina with water, yeast, and salt-as a function of the relative amount of the ingredients. The rheological measurements were carried out by an Anton Paar MCR 102 rheometer, equipped with a plate-plate fixture. In more detail, frequency sweep and creep tests were performed. It was found that doughs obtained with different amounts of ingredients showed significant differences in the rheological responses. The addition of water led to a significant decrease in the viscosity and improved the deformability of the dough. In addition, the yeast addition produced a viscosity decrease, while the presence of salt produced an improvement of the three-dimensional gluten network characteristics and, consequently, of the strength of the dough. In addition to the production process of pani carasau, this work contributes to improving the general performance of the doughs used in the production of flour-and-semolina-based foods

Design of a chemical reactor under microwave irradiation in resonance conditions

Reaction processes often show to be improved by microwave application, but the enhancing effect is not always due solely to the temperature increasing in the medium, which is produced by the radiation exposure. Thus, to study the evolution of such kind of processes needs a strict control of the irradiation conditions and the use of a proper reaction apparatus in which the interaction between radiation and irradiated materials can be precisely defined. The present work is made necessary by the need of operating with controlled and reproducible experimental conditions, and the aim was to design a multi-tube reactor, to work in resonance conditions, inside which the tubes with the fluid to be processed are positioned. In fact, working in resonance conditions allows the irradiated fluid to be exposed to constant microwave power, and the field intensity and power absorption can be accurately calculated and mapped. The cavity was designed by the authors using a proper commercial software for 3D electromagnetic simulation, then the reactor operation was tested by another commercial multiphysic simulation software. The results here presented show the proper geometrical characteristics of the cavity and of the internal tubes to work at 2.45 GHz of frequency while the irradiation power can be varied depending on the needs of the process. The reactor can work with different homogeneous systems, both chemical and biological (enzyme reactions). The future development will be the construction and the real operation of the designed apparatus in order to confirm the simulation results

The new 5 MN hexapod-shaped multicomponent build-up system project.

The new 5 MN Hexapod-Shaped Multicomponent Build-Up System (HSM-BUS) represents a significant progress in the field of reference transducers in the high force range. As any build-up system, the presented HSM-BUS can lead not only to measure forces 5 times higher than the capacity of a each single Uniaxial Force Transducer (UFT), but gives also information about the other components of the force vector and of the moment vector. The goal of the project is mainly to enhance the internal traceability of INRIM force laboratory up to 5 MN, using the HSM-BUS as reference force transducer up the range of 5 MN. Additionally, since this type of BUS is a multicomponent, it would also be used to minimize the spurious component of the force applied by the Standard Force Machine during the calibration of uniaxial force transducers