Microwave processing of food samples: influence of cavity design and dielectric properties

[EN] Microwave-material interactions and electromagnetic propagation phenomena are important to optimize the microwave heating process of food samples. In this study, a 3D numerical modelling of a TE10 rectangular waveguide including microwave antenna and impedance matching elements is proposed. The microwave applicator is aimed to process both solid and liquid food samples. The model illustrates the standing wave patterns and microwave absorbed power within the cavity by taking into account the influence of the screw tuner, quartz windows, shorting plunger, and additional dielectric support plates. The results reveal the importance to consider the real cavity design and the precise dielectric characterization to predict accurate temperature profiles within the food product during the microwave heating. Such a model can be now be used to optimize the food sample geometry to achieve minimum reflected power and better heating uniformity.The authors are grateful to the National Council for Scientific and Technological Development (CNPq, Brazil) for Clarissa Detomi Albuquerque’s PhD scholarship and financial support (process number 232767/2014-9). The authors would also like to thank O. Tantot (XLIM, UMR CNRS 7252) for the dielectric characterization of materials.Clarissa, A.; Curet, S.; Boillereaux, L. (2019). Microwave processing of food samples: influence of cavity design and dielectric properties. En AMPERE 2019. 17th International Conference on Microwave and High Frequency Heating. Editorial Universitat Politècnica de València. 261-268. https://doi.org/10.4995/AMPERE2019.2019.9911OCS26126

Nonlinear trajectory control of high pressure thawing

International audienc

Multiphysics modeling of microwave processing for enzyme inactivation in fruit juices

International audienceMicrowave processing of fruit juice model solution containerized in a cylinder was evaluated by a numerical multiphysics model, aiming to understand the temperature and peroxidase inactivation profiles along processing. In order to rigorously simulate the microwave processing, a finite element model was developed by iteratively coupling electromagnetism, heat transfer, fluid flow and enzyme inactivation. Peroxidase inactivation was determined experimentally, presenting a first-order kinetic behavior (°D C 70 = 234.377 ± 7.068 s, z = 12.072 ± 0.295°C, R 2 = 0.97), which was implemented in the simulation. Enzyme inactivation could be well predicted, considering convection currents and spatial temperature distribution within the sample during microwave heating. Experimental results under various combinations of time and temperature were used to validate the results from simulation. Good agreement was obtained in terms of both temperature at the sample center (R 2 ≥ 0.99) and peroxidase inactivation (R 2 = 0.97). Therefore, the presented results highlight the relevance of a coupled modeling for predicting enzyme inactivation, taking into account the potential presence of cold spots during microwave heating, allowing further process optimization

Model-Based Settings of a Conveyorized Microwave Oven for Minced Beef Simultaneous Cooking and Pasteurization

12th IFAC Symposium on Computer Applications in BiotechnologyThe International Federation of Automatic Control16-18, 2013, December. Mumbai, IndiaInternational audienceA major drawback of microwave processing is the heterogeneity of treatment, which preventsfrom a plenty benefit of its flexibility and rapidity. Most of time, this operation is realized in continuousprocesses, composed of a series of microwave generators with adjustable power. In this paper is proposeda methodology leading to an optimal setting of these powers in order to warrant the expectedmicroorganisms’ inactivation during simultaneous cooking and pasteurization, while preserving quality.It consists in minimizing a multicriteria formulation including hottest and coldest points on the first hand,and final logarithmic inactivation on the other one. The simulation model is composed of a reduction ofthe heat equation via a finite volume scheme with a source term deduced from appropriate closed-formsolutions of the Maxwell’s equations, whereas the non-isothermal inactivation is described by theGeeraerd model. The methodology is carried out by considering treatment of minced beef

Modeling Heat and Mass Transfer in Bread During Baking

conferences COMSOL, octobre 201

Modeling Heat and Mass Transfer in Bread During Baking

conferences COMSOL, octobre 201

Hybrid modelling of cooling-drying process in animal feed-pellets industries

Hybrid modelling of cooling-drying process in animal feed-pellets industries. 9. biennal FOODSIM conferenc

Experimentation of Melting Kinetics Control in a Convective Food Thawing Process

The control of the melting front velocity in some foodstuff has been experimented and is reported in this paper. The single control variable is the external temperature. The position of the melting front is not measured. Advanced control methods as trajectory planning, nonlinear tracking, or feedback linearization are shown to be an effective tools in this pioneering control problem