Emmanuel Purlis- PhD
- Researcher at National Scientific and Technical Research Council
Emmanuel Purlis
- PhD
- Researcher at National Scientific and Technical Research Council
Food engineering ; Modelling ; Transport phenomena ; Porous media
About
44
Publications
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1,385
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Introduction
Research and teaching in Food engineering
Current institution
Additional affiliations
April 2004 - present
Publications
Publications (44)
This paper presents a review regarding several aspects of the development of browning during baking of bakery products, mainly from an engineering point of view. During baking, the formation of colour is due to the Maillard reaction, and caramelization of sugars. Besides the major influence of this phenomenon on the initial acceptance of products b...
A mathematical model for the bread baking process is developed in this work. Experimental data (temperature, water content, weight loss, crust thickness) obtained during baking is used to well understand the simultaneous heat and mass transfer occurring during the process. The evaporation–condensation mechanism is responsible for the rapid heating...
Starch retrogradation and water loss have effects of the same intensity on the increase in firmness in the phenomenon of bread staling. Writing the equations of this system, in order to understand the mechanisms of water transfer in the vapour and liquid phases, is apparently simple. Nevertheless, choices are necessary for the simplifying hypothese...
This paper presents a theoretical approach for optimal design focused on baking, which is based on knowledge about transport phenomena and physicochemical changes occurring during the process. Such approach consists in identifying and defining the critical and quality times of the process, and to find a technological solution to make equal those ti...
A simultaneous heat and mass transfer model proposed to describe the bread baking process is validated. The mathematical model is based on a moving boundary problem formulation with equivalent thermophysical properties and includes the moving evaporation front, the evaporation–condensation mechanism and the development of the crust observed during...
Purpose of Review
The goal of this article is to present a concise review about digital twin (DT) methodology and its application in food processing. We aim to identify the building blocks, current state and bottlenecks, and to discuss future developments of this approach.
Recent Findings
DT methodology appears as a powerful approach for digital t...
The goal of this short review is to introduce a new hybrid modelling approach, i.e. physics-informed machine learning (PIML), to deal with transport phenomena-based problems and related applications in food engineering. To evaluate its potential, we investigate the fundamentals of the method and most relevant contributions.
Overall, PIML is in a de...
Time-temperature profiles (TTP) in food during baking and other heat treatments are essential to understand and characterise a series of changes related to product quality, and for design, control and optimisation of the process. Experimental determination of TTP is not always practical, so mathematical modelling has been applied to characterise an...
This work is focused on transient diffusion processes inside semi-solid and solid agri-food products presenting ellipsoidal shape, i.e. prolate and oblate spheroids and general ellipsoid. Many typical industrial operations like drying, soaking, rehydration, heating, cooking, and cooling, can be effectively modelled by using Fick's law for mass diff...
Volume change and large deformation occur in different solid and semi-solid foods during processing, e.g., shrinkage of fruits and vegetables during drying and of meat during cooking, swelling of grains during hydration, and expansion of dough during baking and of snacks during extrusion and puffing. In addition, food is broken down during oral pro...
The baking process has received quite attention during the last three decades, due to its economic and industrial relevance, and since it is associated with staple foods like bread. Because of the composition and structure of dough, a series of complex, simultaneous and coupled phenomena occur in the product inside the oven, which make very difficu...
This study presents a theoretical and numerical analysis to derive a multiphase model of heat and mass transfer for low intensity/temperature convective drying of hygroscopic porous materials, with focus on food products. Some commonly used simplifications in modelling drying and similar processes are evaluated and a reduced model is obtained conse...
Baking is a complex transformation process since many coupled physical phenomena take place within the product. For practical industrial purposes, it would be desirable to count on simple methods to predict accurately the process time. Unlike food preservation operations, two different process times can be defined: the critical or minimum time is d...
El tostado de pan puede clasificarse como un segundo proceso de horneado, o bien como un proceso de secado intensivo de pan. En términos generales, es un proceso de preservación de alimentos, ya que implica la evaporación térmica del agua del pan, hasta un valor de actividad de agua que permita la conservación del producto. El tostado es un proceso...
Muchos procesos de preservación y/o transformación en ingeniería de alimentos tienen una gran demanda energética, en especial, aquellos que involucran la evaporación térmica de agua, como el secado, horneado y tostado. Estos procesos requieren más energía que otras operaciones, como la refrigeración, congelación y esterilización. La diferencia radi...
As development of color in bakery products is of importance, this chapter reviews the browning phenomenon with emphasis on engineering aspects. This perspective of browning includes basic concepts for understanding the chemistry of reactions, the consequences for product quality, and process design topics, such as measurement, modeling, control, an...
Retrogradation of starch and water loss have an effect of the same intensity of the firmness increase in the phenomenon of bread staling. To understand the transfer of water during staling, we developed three models. In the first two models, crust is considered as a membrane characterised by its water vapour permeability. In the third model, crust...
This paper presents a theoretical approach for optimal design of the baking process. Conventional baking of bread was taken as subject of study, and simulation of previously validated models was used to investigate the process. The proposed approach is based on the definition of two different times for the baking process: a critical time, i.e. a mi...
This paper presents a study of bread baking, mainly from a technological point of view, i.e. focused on transport phenomena and major quality changes occurring during the process. Such study was carried out by numerical simulation of a previously developed and validated mathematical model, which describes the simultaneous heat and mass transfer (wi...
This paper presents a mathematical model for describing processes involving simultaneous heat and mass transfer with phase transition in foods undergoing volume change, i.e. shrinkage and/or expansion. We focused on processes where the phase transition occurs in a moving front, such as thawing, freezing, drying, frying and baking. The model is base...
A procedure to obtain realistic geometric models of foods having different inner tissues or sub-regions is developed. The proposed methodology consists in colour segmentation of food images using a distance criterion, obtaining a reduced set of pixels representing univocally all boundaries of food sub-regions, and finally construction of the geomet...
In this work, we study the development of browning at bread surface during baking. Computer vision is applied to follow the progress of browning at surface, while the variations of temperature and water activity are obtained by numerical simulation of a mathematical model previously validated. The formation of the bread crust is a complex process w...
Three-dimensional geometric models of irregular food were constructed to contribute to process modelling area shedding light on geometry development aspects. Object reconstruction was performed using a cross-sectional design technique from magnetic resonance images. Boundaries of cross-section images were approximated by B-Spline curves after an im...
The bread baking process was analyzed through simulation of a mathematical model, which was previously developed and validated against experimental data. Typical baking conditions were simulated using the finite element method and a three-dimensional and irregular geometry obtained by image processing. Two baking indexes were employed: the complete...
A simple meat cooking model is evaluated, using three-dimensional irregular geometries as simulation domains and the finite element method. Experimental meat cooking was carried out in a convective oven to obtain process information and to assess the model accuracy, which is determined through the cooking time and the weight loss estimation. In bot...
We investigate the spatially extended Hastings–Powell model in one and two dimensions with constant diffusion coefficients and nonflux boundary conditions. Nowave zones, spirals and chaos are found. An absolute instability of the spirals produces a transition to chaos. A constant number of defects, linearly increasing with the bifurcation parameter...
Un medio excitable es un sistema en el que estímulos suficientemente grandes generan ondas de activación, mientras que estímulos pequeños decaen conduciendo al sistema nuevamente al equilibrio. La reacción de Belousov- Zhabotinsky (BZ) es un ejemplo típico de sistema químico excitable. En un medio espacialmente extendido puede ser estimulada electr...
Investigamos el modelo de Hastings-Powell (HP) extendido en el espacio en una y dos dimensiones, usando coeficientes de difusión constantes y condiciones de contorno de no-flujo. El modelo HP fue introducido originalmente en el contexto de procesos ecológicos no lineales para describir una cadena trófica de tres especies, aunque también representa...
The objectives of this work were: (i) to construct real geometric models for different carcasses and (ii) to simulate common preservation processes such as chilling or cooking of carcasses.
Three-dimensional reconstruction of general solid food materials was performed using a reverse engineering method based on a surface cross-sectional design. Digital images of cross-sections of irregular multi-dimensional foodstuffs were acquired using a computer vision system, and image processing was performed to obtain the actual boundaries. Thes...
Un paso fundamental en la simulación numérica de procesos de interés en ingeniería de alimentos es la selección de una representación geométrica adecuada del alimento, para ser utilizada como dominio de simulación. Debido a la dificultad para describir correctamente la forma real (generalmente irregular) de los alimentos, se han considerado ampliam...
The development of browning at bread surface during baking is an important quality index. In this paper, the colour (CIE L∗a∗b∗ parameters) of bread surface was measured by computer vision. Also, the weight loss variation was determined during the process. Baking experiences were performed at 180, 200 and 220°C under natural and forced convection....
La representación geométrica de un alimento es indispensable para el modelado y la simulación numérica de diferentes procesos del campo de ingeniería de alimentos. Generalmente, se han considerado geometrías simples y regulares, debido a la dificultad para describir fielmente la forma de los objetos reales.
El objetivo de este trabajo fue obtener r...
El volumen, el área de sección, el volumen específico y la densidad aparente son utilizados como parámetros de calidad y variables de ajuste y optimización del proceso de horneado de panificados. Por ejemplo, en la evaluación de condiciones de congelación y almacenamiento de masas, en la optimización de calidad y costo de la producción de pan, y en...
Bread baking is a complex process in which several physical, chemical and biochemical changes in the product are involved. These changes are volume expansion, water evaporation, porous structure formation, protein denaturalization, starch gelatinization, crust formation and browning reactions. Mathematically, the process could be described as a sim...
The surface area and volume of food materials are parameters of great importance in the food engineering field, fundamentally in many processes involving heat and mass transfer. However, they are very difficult to obtain experimentally due to natural irregularity and variation of size and shape of food, even for a same type of material. Therefore,...
Aunque es evidente la presencia de predadores en sistemas de barros activados, ninguno de los modelos empleados actualmente para describir los sistemas de barros activados incorpora su presencia. El objetivo del presente estudio fue desarrollar un modelo matemático basado en una red trófica típica presente en un sistema de barros activados que perm...
The production of ready-to-serve meals has been in continuous increase in the last years. Notwithstanding, there is a lacking of accurate methods to predict cooking times to ensure final safe products of optimal quality. Mathematically, cooking can be considered as simultaneous heat and mass transfers between food product and oven ambient. Modellin...
In the present work a numerical model is used to simulate the cooking of a piece of meat. The aim is the development of a methodology that allows to obtain an image of the real geometry of the food (three-dimensional and irregular), using digital image processing and computational vision. In the proposed model, the heat and mass balances are solved...
Baking is a complex process that brings about a series of physical, chemical and biochemical changes in the products, such as volume expansion, water evaporation, formation of a porous structure, protein denaturalization, starch gelatinization, crust development and browning reactions.
Mathematically, the process could be described as a simultaneou...
El objetivo de este trabajo fue obtener mediante técnicas CAD (Computer Aided Design) la representación de la geometría real de un alimento y realizar el modelado, y posterior simulación, por medio del método de elementos finitos (FEM).
Mediante el método propuesto se pretende facilitar el preprocesamiento de los datos requeridos en el campo del m...
