Search

National audience; Vacuum concentration and drying are valuable techniques for the removal of water and the resulting stabilization of most dairy and feed ingredients. In this study, we present methodology to calculate and compare the energy consumption for the production of dairy and feed powders at different processing stages of the dehydration process. The results show that the energy costs to produce 1 kg of dairy and feed powders were 6,120 and 20,232 kJ · kg−1 powder for pregelatinized starch and soy protein concentrate, respectively. For dairy products, the values were 9,072 and 15,120 kJ · kg−1 for fat-filled and demineralized whey powders, respectively. According to the type of product (biochemical composition, ratio of bound and free water) and process (demineralization, vacuum evaporation, lactose crystallization, roller and spray drying), the energy consumption for the production of powders could be calculated. These findings could be valuable for studies focusing on improvement of energy efficiency for dairy and feed processes.

En revisitant complétement le procédé de production des probiotiques avec une vision intégrée et multidisciplinaire, les chercheurs du laboratoire « Science et Technologie du Lait et de l’œuf » (STLO) innovent avec une méthode de séchage par atomisation simplifiée.[br/] Qu’il s’agisse de levains de fermentation ou de probiotiques, l’utilisation de micro-organismes par l’industrie nécessite le recours à des procédés de production et de conservation susceptibles d’altérer l’intégrité structurelle et fonctionnelle des cellules. La lyophilisation qui agit par combinaison du froid et du vide, est la méthode de séchage la plus répandue à grande échelle, pour conserver des bactéries. Si elle apparait comme une solution pratique pour stabiliser des populations microbiennes et faciliter leur manipulation et stockage, elle reste néanmoins onéreuse et gourmande en énergie. D’autres alternatives comme l’atomisation et la fluidisation existent, mais font appel à la chaleur, avec pour conséquences, des taux de survie inférieurs et des pertes de fonctionnalité des souches.

National audience

absent

absent

Spray drying is a well-established technique to convert a liquid solution into individual solid particles. It is widely used in the dairy industry, especially in the whey sector. In fact, the dairy industry has to process huge amounts of whey each year. Because of environmental and economic factors, as well as the potential benefits for health, whey is no longer considered a waste product. It is therefore of the utmost importance to process whey properly to supply the ingredient market with high quality products. However, whey is not an easy product to process because it contains a great deal of free water, lactose, soluble proteins and varying amounts of minerals, especially calcium, phosphate and various monovalent ions. If lactose is not properly crystallised, whey cannot be spray dried correctly without a reduced flow rate and decreased functional properties of the powder. Whey composition is unfortunately highly variable, which makes it difficult to anticipate process optimisation for further processing. Lactose crystallization is a critical step in the processing of whey and its permeates concentrated by evaporation before spray drying. In this overview, we propose several approaches to improve the performance of whey powder processing by using physicochemical and process information. Several examples of process optimization through improved understanding of vacuum evaporation, lactose crystallization and spray-drying are detailed. The final aim of this overview is to contribute to greater understanding of lactose crystallization and to propose an ideal plant to produce whey powders of high value, quality and energy efficiency with a low environmental impact.

absent

absent

Serão apresentados e descritos de maneira simples os mecanismos e princípios das operações unitárias indispensáveis para a produção de produtos lácteos desidratados. Neste contexto serão abordadas a concentração por evaporação à vácuo, a cristalização da lactose e a secagem por atomização/pulverização, incluindo a parte de otimização energética. Exemplos concretos serão abordados.

Serão apresentados os meios necessários para conservar os pós, fazendo a ligação indispensável entre a atividade de água e a transição vítrea que estão associadas aos parâmetros de secagem. Exemplos concretos serão abordados.

absent

In recent years, the milk fat globule membrane (MFGM) has attracted the attention of scientists and industrials because of its interesting functional, nutritional and health properties. The properties of the MFGM result from its chemical composition, but they may also be influenced by the capacity of the MFGM components to be specifically structured. The objective of this work was to investigate the organization of the MFGM in situ in milk, using CLSM and adapted fluorescent dyes. Our work revealed i) the lateral segregation of sphingomyelin (SM;25%polar lipids) in domains surrounded by the fluid matrix of the glycerophospholipids , ii) that the SM-rich domains diffuse in the plane of the outer bilayer of the MFGM as a function of time and are devoid of proteins . These SM-rich domains have been characterized whatever the size of milk fat globules and in milks from various species.We propose a new model for the organization of the MFGM. These original results raised the question of the role played by these SM-rich domains on the functional and nutritional properties of milk fat globules. Directions for future research studies will be discussed. Our recent findings about the specific physical properties of SM will be presented.

Evaporation is an important step in dairy processing to concentrate milk constituents. During this step, the mineral fraction, especially calcium phosphate, is concentrated and can precipitate depending on the physico-chemical conditions. The objective of this study was to evaluate the physico-chemical conditions influencing the calcium phosphate precipitation during evaporation as a function of concentration factor from milk ultrafiltrate (UF), microfiltrate (MF)) and mineral solutions. Experiments were carried out at 3 concentrations (5, 10 and 20mM) of citrate at pH 6.75 or by adjusting the pH (6.0, 5.3 and 4.6) of UF, MF and calcium phosphate solutions as a function of concentration factor in evaporator. Different approaches were utilized like a theoretical approach using the MILK salts GLM, water evaporation with rotavapor and water desorption. It was observed that calcium phosphate precipitation increased as a function of concentration factor during evaporation. The precipitation was strongly influenced by pH and citrate concentration. In perspectives, the calcium phosphate precipitate obtained during evaporation will be characterized by using laser granulometry, zetametry, and microscopy.

Minerals found in milk have a complex composition which evolves according to pH and technological processes. Among milk components, polar lipids (phospholipids and sphingomyelin) are amphiphilic molecules with a polar head group highly sensitive to ions. Milk polar lipids are mainly located in the membrane surrounding fat globules. They can also be concentrated from by-products of the dairy industry (e.g. buttermilk) and used for their interesting nutritional and functional properties as well as for encapsulation after formation of liposomes. Although the minerals found in milk and dairy products can affect the functional properties of polar lipids and their structural organisation, scientific data are scarce. The objective of the work was to investigate the properties of milk polar lipids as a function of the pH, the ionic strength and the type of minerals: monovalent or divalent ions. The combination of chemical and biophysical methods (zeta potential, turbidimetry, microscopy techniques) was used to characterise polar lipids properties and organisation. Changes in milk polar lipids properties and organisation will be presented as a function of their mineral environment. Decrease in pH and increase in ionic strength lead to a reduction i) of zeta-potential values, ii) of the electrostatic repulsions between polar lipids particles until their aggregation and phase separation from water. Among milk minerals, calcium highly affects polar lipids properties. This work contributes in a better understanding of the physical stability of milk fat globules and will improve the utilization of milk polar lipids for different food applications (cheeses, infant formulas…).

Lactose crystallization is a critical step in the processing of whey and permeates, concentrated by evaporation, before spray drying. Despite, numerous experimental studies, understanding and mastering of this unit operation remain a challenge for both industrial and scientific communities. In order to study the effects of whey constituents on lactose crystallization, a model based on population balance and taking into account mutarotation was implemented. Outputs were the nucleation constants (B0, kn0) and the growth rate constants (k g0, g0). Batch crystallization of a lactose solution (70 g.100 g 1 water) was studied with and without addition of various organic acids, salts, galactose and proteins. Kinetics and crystal size distributions were monitored using refractometry and laser light scattering. Factorial analysis of the results highlighted that the presence of organic acids (lactate, citrate) leads to faster crystallization and confirmed the fact that whey proteins are slowing down the crystal growth step. The results of this study make a contribution towards a better understanding of lactose crystallization.

Le présent ouvrage présente un diagnostic des minilaiteries dans quatre pays de la zone : le Burkina Faso, le Mali, le Niger et le Sénégal. Il analyse les forces et les faiblesses de ces entreprises qui ont mis au point des procédés de transformation originaux et créé de nouvelles filières commerciales.

Increasing the shelf-life of sensitive substances and targeting the release of nutritional/bioactive molecules are among the great challenges for the food industry. The development of food products with embedded encapsulation devices used to reach these objectives, constitutes a growing market. Milk proteins are biopolymers that are chemically and structurally versatile and are well adapted to several encapsulation purposes. Therefore, in this paper, the strategies, techniques, advantages and trends associated with the use of milk proteins as encapsulating device are reviewed. Special attention is given to the novel potential of reversibly co-assembled protein structures as encapsulating devices.

International audience; Considered as relevant levers for developing countries and territories, terroir products have focused the attention of many actors, researchers and policy for over 30 years. Indeed, if the products GI protection approaches have been successful in the EU countries, and particularly in France, they are still under construction in Mediterranean countries. The researches presented in this book are interested in the construction of terroir products in Mediterranean countries. They take different theoretical approaches in economics and management and are based on a variety of fields.; Considérés comme des leviers de développement des pays et des territoires, les produits de terroirs ont focalisé l’attention de nombreux acteurs, chercheurs et politiques depuis plus de 30 ans. En effet les démarches de protection des produits sous IG ont porté leurs fruits dans les pays de l’UE, et en particulier en France, elles sont encore en construction dans les pays méditerranéens. Les travaux de recherche présentés dans ce cahier s’intéressent à la construction des produits de terroirs dans les pays méditerranéens. Ils empruntent différentes approches théoriques en économie et gestion et se basent sur une diversité de terrains.

International audience; This paper explains the modes of transactions and forms of coordination between the various agents of the dairy industry in the Chéliff region in Algeria. The main objective is to understand the strategy developed for sale or supply. It seems that forms of coordination exist, vary from one region to another, depending on the nature of the system (formal or informal). The informal one is an effective system of economic and social organization insofar as it ensures a joint coordination beyond the spot market by forming reciprocal agreements based on trust and oral contractual relationships. However, the forms of coordination between formal agreements are between “ products-specificity contracts “ and “production factors” contracts in a framework governed by state regulations in terms of quantity, price and quality whose efficiency is higher for small private dairies in comparison with state-run dairy farms by the use of hybrid coordination mechanisms.; Le présent papier explicite les modes de transaction et formes de coordination entre les différents agents de la filière lait dans la région de Chéliff en Algérie. L’objectif principal est de comprendre la stratégie développée en vue de vendre ou de s’approvisionner. Il semble que les formes de coordination existantes, varient d'une région à une autre et selon la nature du système (formel ou informel). Le système informel demeure un véritable système d'organisation économique et social dans la mesure où il arrive à assurer une coordination mixte dépassant le marché ponctuel, en ayant recours à des accords réciproques basés beaucoup plus sur la confiance et des relations contractuelles orales. Cependant, les formes de coordination formelles se situent entre les accords de type "contrat spécificité des produits " et les contrats "facteurs de production " dans un cadre global régi par une réglementation dictée par l'Etat en matière de quantité, de prix et de qualité dont l’efficacité est plus élevée pour le circuit des mini-laiteries privées en comparaison avec celui de la filiale Etatique grâce au recours à des mécanismes de coordination hybride.

Plusieurs modèles laitiers cohabitentQuels modèles de développement proposer aux éleveurs laitiers de la planète ? Les réponses sont multiples, ont montré les chercheurs de l’Inra et du Cirad lors d’un premier colloque international à Rennes.Les apparences peuvent être trompeuses : les élevages agro-pastoraux du Ferlo, au Sénégal, font preuve d’une remarquable adaptabilité aux aléas climatiques et économiques.Les apparences peuvent être trompeuses : les élevages agro-pastoraux du Ferlo, au Sénégal, font preuve d’une remarquable adaptabilité aux aléas climatiques et économiques.La Bretagne s’interroge sur son avenir laitier. “Il nous paraît important de regarder ce qui se passe ailleurs” explique Sylvie Lortal, de l’Inra de Rennes. Elle est l’une des organisatrices de ces Premières rencontres internationales sur “Le lait : vecteur de développement”, qui se sont déroulées à l’Agrocampus de Rennes les 21, 22 et 23 mai.“Il existe un modèle dominant, celui des vaches Holstein, regroupées dans de grandes structures. Pourtant, 38 % du lait dans le monde ne passe par des laiteries. Et un cinquième du lait n’est pas du lait de vache. Il existe une diversité. Quelle place accorder aux autres modèles ?” interroge Christian Corniaux, du Cirad.La ferme des 60 000 vachesAu cours de la session du 22 mai, consacrée aux “Spécificités territoriales et dynamiques de développement laitier”, les chercheurs ont mis en relief cette complexité mondiale. Guillaume Duteurtre, du Cirad, a montré que “les modèles de développement sont à prendre avec prudence, parce qu’ils ne reflètent pas la diversité des trajectoires locales”. Ils existent pourtant, et peuvent être retenus par des Etats comme marche à suivre pour leur agriculture (voir Ils le disent). Certains modèles portent sur un type de ferme, d’autres sur un type d’organisation. Il y a le modèle Holstein mécanisé en bâtiment, “ça marche même en Arabie Saoudite”. On y trouve une ferme de 60 000 bovins ! Aux Etats-Unis, 40 % du lait est produit dans des exploitations de plus de 2 000 vaches, et 30 % dans des unités de 500 à 2 000 VL. Il est adossé à des laiteries modernes “clé en main qu’on trouve aussi bien à Dakar qu’au Caire”. A côté de cela, on trouve l’agriculture familiale traditionnelle : le système agro-pastoral d’Afrique de l’Ouest fait vivre des centaines de milliers de familles. Entre les deux se développent des systèmes familiaux avec des “vaches métis”, où l’on croise des races locales avec de la génétique importée. Ces vaches sont nourries avec de l’herbe à éléphant, “pilier du développement mondial de ce modèle”.Si le modèle industriel semble productif, il faut se méfier des apparences : par exemple, sa valeur ajoutée par unité de surface n’est pas meilleure que dans des fermes familiales, indique le chercheur. “Les fermes diversifiées dégagent un revenu par vache plus important que les fermes industrielles.”Dans la balance, il n’y a pas que des arguments techniques et de productivité, on doit aussi prendre en compte les dimensions économiques et sociales.

La dépendance alimentaire de l'Algérie a obligé l'État dès les années 1970, à mettre en oeuvre une série de politiques d'amélioration de la production laitière. Cependant ces politiques ont souvent été peu efficaces. Le secteur informel représente un défi majeur pour l'Etat car il semble insensible aux politiques publiques dédiées à la structuration de la filière lait tant à l'échelle régionale que nationale. Et pourtant les pratiques informelles présentent un ancrage socioculturel et régional qui leur permet de fonctionner activement et efficacement. La présente thèse a comme principal objectif de comprendre les logiques formelles et informelles, et leur articulation, à l'oeuvre dans le bassin laitier de Souk Ahras situé au nord-est de l'Algérie, où le secteur informel canalise plus de 60 % des quantités de lait mises en marché. Ces logiques sont appréhendées sous l'angle de deux théories néo-institutionnelles complémentaires : la théorie des coûts de transaction et la théorie des institutions de North. Un important travail de collecte et d'analyse de données a été réalisé sur l'ensemble de maillons de la filière lait à Souk Ahras, de la production jusqu'à la consommation. Nos résultats montrent la pertinence d'appréhender les notions de formel et d'informel par les pratiques plus ou moins respectueuses des normes et des règles publiques, plutôt que par les acteurs ou les circuits. Cette thèse met en évidence deux grands ensembles de facteurs explicatifs du comportement des acteurs: les facteurs endogènes (recherche d'efficience économique en termes de coûts de production et de transaction) et les facteurs exogènes (la saisonnalité et les incitations du marché et de l'environnement institutionnel). L'incapacité des acteurs à mettre en place certains investissements nécessaires à l'enforcement des règles formelles (coûts de production et de transaction élevés), leur conduit à des pratiques informelles. La saisonnalité est une source d'incertitude qui réduit la crédibilité des engagements des acteurs et limite par conséquent leur capacité d'investissement et d'enforcement des règles formelles. Le marché favorise certaines pratiques informelles via un système de prix plus rémunérateurs pour les produits issus de ces activités. Bien qu'il incite à l'adoption de certaines règles formelles, l'environnement institutionnel reste défaillant vu l'inefficacité de ses institutions et de son système d'incitation. Les résultats émis dans cette thèse permettent des recommandations pour les politiques publiques dédiées à la structuration et au développement de la filière lait local.

Comprendre les richesses des laitsFin mai, les premières Rencontres internationales du lait ont réuni plus de 200 acteurs de cette filière à Rennes.C’est un aliment à part. La richesse de sa composition, mais aussi sa dimension symbolique, sa diversité font du lait, ou plutôt des laits - car 1/5e de la production n’est pas du lait de vache ! -, un produit complexe. C’est pour mieux comprendre toutes ces richesses que l’université française d’agronomie Agreenium(1) a organisé, du 21 au 23 mai dernier à Rennes, les premières Rencontres internationales du lait.« L’idée de départ était de prendre du recul sur ce qui se fait dans le domaine du lait aujourd’hui, dans le monde entier, explique Sylvie Lortal, chercheuse à l’Inra de Rennes et coorganisatrice de l’événement. Et de donner la parole à des acteurs locaux, venus d’horizons différents. » Un accent particulier est mis sur le rôle des femmes. « Il est primordial. Dans certaines sociétés, les Peuls, par exemple, tout appartient aux hommes sauf le lait. C’est parfois la seule source d’émancipation. » Mais ce colloque voulait aussi tirer la sonnette d’alarme sur la mondialisation qui touche le secteur laitier. « Aujourd’hui de grands groupes tentent de s’imposer et de standardiser les productions. Mais cela peut avoir un effet délétère. Certains laits sont particulièrement adaptés à un milieu. Le lait de yack, très gras, au Tibet ou le lait de chamelle, riche en vitamine D, dans les déserts où les fruits sont rares. Cette standardisation est un risque nutritionnel, économique, et culturel ! » Les organisateurs ont ainsi souhaité se passer du soutien financier de l’industrie laitière - à l’exception de Triballat, considérée comme une entreprise régionale, à vocation durable.« Ces rencontres nous permettront aussi de prendre contact avec d’autres acteurs de la recherche pour mieux répondre aux demandes et découvrir de nouveaux défis. Notre espoir est aussi de pouvoir organiser la seconde édition ailleurs dans le monde. » Le rendez-vous est donné.

absent

The microbiology of dried milk products is governed by the quality of the raw material, the conditions employed during manufacture of the product, and any postprocessing contamination. Most dried milk now is produced by spray-drying, and therefore, other drying methods (e.g., roller-drying or freezedrying) are excluded from consideration in this chapter. Because of the complexity of the manufacturing process, each step is considered in turn.

absent

absent

International audience; Among the food industries, the dairy industry has undoubtedly known the largestintroduction of membrane technologies (microfiltration (MF), ultrafiltration (UF),nanofiltration (NF), and reverse osmosis (RO)). In the 1970s, the development ofthe membrane processes resulted in the emergence of a new whey industry, whichis one of the best demonstrations of what can be done with well-thought use ofseparation techniques and biotechnologies. Whey is the liquid coproduct gener-ated during cheese and casein productions. Because of its high water content andrelatively high sugar andmineral contents, whey isused to be considered as awaste product without value. In the past, whey was disposed off as sewage, di-rectly dumped into the sea or the river despite its high biological oxygen demand(BOD5=30–50 g L–1for1,000Lofwhey),spreadonfieldsoratbestusedforfeed-ing pigs. In the 1980s, more than two thirds of whey production was still disposedoff as waste with a detrimental effect on the environment. The widespread adoptionof the membrane processes, such as UF, within the last quarter of the twentieth cen-tury represented a major technological evolution in facilitating the recovery of wheyproteins in a near native form from whey.Additionally, the increased knowledgeon the technological and biological functions of whey constituents has drawn in-terest of researchers, manufacturers, and consumers, and has boosted the demandand thereby the market for high-value wheyingredients for functional or health-promoting foods. By applying membrane processes, a significant amount of thewhey produced is then being processed, mainly for the recovery of its protein con-tent (Figure 2.1). The development of value-added products from whey compoundsrepresents one of the most promising applications of membranes in the dairy in-dustry today. For economic reasons, such a development is made possible only bylarge dairy processors, and whey is still treated as a waste by small processors andin most developing countries

International audience; The drying of milk concentrate droplets usually leads to specific particle morphology influencing their properties and their functionality. Understanding how the final shape of the particle is formed therefore represents a key issue for industrial applications. In this study, a new approach to the investigation of droplet−particle conversion is proposed. A single droplet of concentrated globular proteins extracted from milk was deposited onto a hydrophobic substrate and placed in a dry environment. Complementary methods (high-speed camera, confocal microscopy, and microbalance) were used to record the drying behavior of the concentrated protein droplets. Our results showed that whatever the initial concentration, particle formation included three dynamic stages clearly defined by the loss of mass and the evolution of the internal and external shapes of the droplet. A new and reproducible particle shape was related in this study. It was observed after drying a smooth, hemispherical cap-shaped particle, including a uniform protein shell and the nucleation of an internal vacuole. The particle morphology was strongly influenced by the drying environment, the contact angle, and the initial protein concentration, all of which governed the duration of the droplet shrinkage, the degree of buckling, and the shell thickness. These results are discussed in terms of specific protein behaviors in forming a predictable and a characteristic particle shape. The way the shell is formed may be the starting point in shaping particle distortion and thus represents a potential means of tuning the particle morphology.Anglais

Some of the critical moments and factors influencing the hygienic quality of milk were investigated at a smallholder cooperative in Costa Rica from which all the members delivered milk to a processing plant. Twenty-two farmers provided data for this study. Milk from all lactating cows was examined with the California Mastitis Test (CMT). Apparent mastitic milk was processed for bacteriological investigation (BI). Additionally, milk samples were collected from storage containers for somatic cell count (SCC) and for BI. Out of the 22 farms 10 were selected for further study on the hygienic quality of the milk sampled at specific critical moments during handling, storage and after transportation to the processing plant. Point prevalence for CMT-positive samples was 21.8%, 36.6% and 28.4% for the months of June, August and October, respectively. The incidence rate for CMT-positive samples for this period was 27.8%. Eighty-three out of 126 milk samples taken from storage containers for SCC contained less than 400,000 cells/ml. Eight percent of the CMT-positive milk samples contained S. aureus. Twenty-eight percent of the milk samples from storage containers contained S. aureus and 79% of the samples E. coli. All milk samples from storage containers obtained at the processing plant had CFU counts exceeding 2.106 cells/ml. This milk was severely contaminated with bacteriological agents from environmental origin. Cooling of the milk was found to be inadequate. The udder preparation method, unclean milk equipment and the water used for cleaning purposes were the main sources of milk contamination.

Vacuum concentration and dehydration by spray drying are valuable techniques for the evaporation of water and are used to stabilize most dairy ingredients. In view of the increasing development of filtration processes, there is a need for the dairy industry to improve their understanding of the effects of controlling these processes on the concentration and spray drying and hence on the quality of protein powders. Several authors have reported that proteins have an important role in the mechanisms of water transfer during drying and rehydration. The residence time of the droplet and the powder in the spray dryer is so short that it is very difficult to implement studies on the mechanisms of the structural changes in the protein without fundamental research into the process/product interactions. However, many studies have reported that the main structural and functional modifications occur before spray drying; that is, during concentration by vacuum evaporation and heat treatment. Following an extensive introduction focusing on dairy powders, this article covers three significant areas: an overview of the main dairy powder processes, the properties of these powders, and the effects of the processes on powder quality.

Dry heating is commonly used in food and pharmaceutical industries to decontaminate heat-sensitive samples such as egg white or therapeutic protein products. Under these conditions thermal stability of proteins is increased and the changes in protein structure are limited.However, it was noted that the functionalities of the dry heated proteins are changed: for instance lysozyme, a poor foaming agent, gives stable foams after dry heating even if the secondary and tertiary structure of the protein are not affected. This discovery expends the use of dry heat treatment for functionalizing a wide variety of food proteins, even to those that resist wet-heat treatments of decontamination. A clear picture of dry-heat induced modifications of proteins is necessary especially for those dedicated to the formulation of infant formula. In this study, LC-MS/MS was used to track the chemical modifications on milk proteins as illustrated here with α-lactalbumin. The samplesadjusted to pH 6.5 and water activity a w= 0.23 were dry heated at 100°C for up to 24 hours. Dry heat treatment traps a fraction of α-lactalbumin molecules into non-native monomers.These non-native monomers were characterized by the loss of one or two water molecules per α-lactalbumin molecules. Using tandem mass spectrometric peptide mapping, these chemical modification were attributed to i- the formation of pyroglutamic acid from the N-term glutamic acid and ii- the formation of an internal cyclic imide at position Asp64 . The structural and functional consequences of theses modifications are discussed.

Milk concentration and spray drying are highly energy-intensive operations, for which energy consumption accounts for about 25% of the French dairy processing industry. A major challenge consists then in the design and development of sustainable dairy concentration processes which integrate technical, economic and environmental criteria. For this purpose, systems oriented tools have already been developed in the chemical industry by using a systemic approach combining modelling, simulation, and optimisation. Despite the proximity of chemical with food and bioengineering sectors, the utilization of such an approach for the modelling of dairy processes suffers from a lack of process models, more particularly when the whole process is considered and when concentration processes are involved. In that context, this work constitutes a preliminary study towards the development of a methodological framework for modelling and optimizing dairy processes. The proposed strategy consists in the combination of a chemical process simulator (ASPEN PLUS 7.3, AspenTech, Inc.) with an environmental model based on Life Cycle Assessment concepts. The simulated process concerns milk powder production, and more particularly milk concentration prior to drying, involving pre-heating, pasteurization, and evaporation steps. The process model performances are assessed through a sensitivity study on the number of effects in the evaporator, and the environmental impacts associated to the various steam requirements involved are quantified according to several scenarios.; La concentration et le séchage du lait sont des opérations très consommatrices d’énergie, pour lesquelles la consommation d’énergie compte pour près de 25% dans l’industrie laitière française. Un défi majeur consiste alors à concevoir et développer des procédés laitiers de concentration qui intègrent des critères techniques, économiques et environnementaux. Dans ce but, des outils orientés systèmes ont déjà été développés dans les industries chimiques en utilisant une approche systémique qui combine modélisation, simulation, et optimisation. Malgré la proximité du secteur de la chimie avec les secteurs agroalimentaire et de la bio-ingénierie, l’utilisation d’une telle approche pour la modélisation des procédés laitiers soufre d’un manque de modèles de procédés, plus particulièrement lorsque le procédé est considéré dans son ensemble (de la matière première au produit final) et d’autant plus lorsqu’il s’agit de procédé de concentration. Dans ce contexte, ce travail constitue une étude préliminaire en vue du développement d’un cadre méthodologique pour modéliser et optimiser les procédés laitiers. La stratégie proposée consiste à combiner un simulateur de procédés chimiques (ASPEN PLUS 7.3, AspenTech, Inc.) avec un modèle environnemental basé sur les concepts de l’Analyse du Cycle de Vie. Le procédé simulé concerne la production de poudre de lait, et plus particulièrement la concentration du lait avant séchage, ce qui implique des étapes de préchauffage, pasteurisation, et évaporation. Les performances du modèle du procédé sont évaluées à travers une étude de sensibilité sur le nombre d’effets dans l’évaporateur, et les impacts environnementaux associés aux divers besoin en vapeur considérés sont quantifiés en fonction de plusieurs scénarii.

absent

absent

Ce séminaire scientifique montre l’orientation nouvelle des recherches menées au sein de l’UMR STLO en termes de technologie des procédés laitiers. L’éco-conception est la ligne directrice de ce séminaire. Le programme est : Eco-conception : définitions et démarches développées au STLO Présentation de la Plateforme INRA pour l‘analyse multicritère de la durabilité (Means) Mise en place d'une démarche d'éco-conception dans les itinéraires technologiques : cas dans le domaine du fractionnement de protéines et lipides laitiers Intérêt de l'instrumentation dans une démarche d'éco-conception : Cas d’un atelier de concentration-séchage idéal Caractérisation du procédé d’évaporation sous vide: démarche et intérêts Intérêt de la modélisation dans l'éco-conception : cas de l'évaporation sous vide.

Pour répondre à ses objectifs, l’industriel laitier doit impérativement utiliser des laits crus qui doivent être de qualité en termes microbiologique et biochimique de façon à ce qu’ils soient transformés selon un cahier des charges bien précis. Le produit final doit être celui attendu par le transformateur et consommé sans aucun risque sanitaire. Il s’avère que dans certains cas le lait cru soit d’une qualité non maitrisée avec comme conséquence une mauvaise transformation et un produit final de mauvaise qualité. Deux exemples reliant qualité des laits crus et transformation (fromages et en lait UHT) sont présentés.

International audience

The design and development of sustainable food processes, which integrate technical and economic criteria, satisfy customer demands, and are less harmful to ecosystems constitutes a major challenge in a context of global changes (climate change, energy scarcity and energy price increase,...). An interesting way to meet these constraints entails a systemic approach combining modelling, simulation, and optimisation. Although methodological tools have been developed in the chemical industry (Steffens et al. (1999), Azapagic et al. (2011), Ouattara et al. (2012)), this kind of approach suffers from a lack of available models that can be applied in the food processing industry. The aim of this work is to develop a framework for the ecodesign of food processes, with a focus on sustainable milk proteins concentrating systems. A systemic approach is proposed in this paper, involving process modelling and simulation of a highly energy-consuming milk process coupled with its associated environmental assessment. More precisely, the approach combines the use of a flow-sheet simulation software tool with a commercial Life Cycle Assessment (LCA) software tool. The process to be studied leads to the production of milk powder from whole milk. The main principle is to concentrate a fat-standardised milk with a number of unit operations, i.e., skimming, homogenisation, pasteurisation, evaporation, and spray drying. The energy consumption of concentration and drying processes alone accounts for 25% of the dairy processing industry energy consumption. These operating steps thus require to be optimized to improve the overall performance of the whole process evaluated through the proposed systemic approach. Literature review about process simulation and environmental analysis in the milk industry demonstrated that both aspects are seldom simultaneously treated: environmental assessment is mostly achieved with fixed process operating conditions. The analysis of the necessary degree of granularity of the related models could lead to the selection of the Aspen Plus® (Aspen Technology, Inc.) software, because of its substantial unit operation models library, and a strong capacity to integrate and model new components (not included in its built-in database). The simulation results give the material and energy flows, which are analysed and compared with experimental results. The LCA of the process is performed with the SimaPro® software, and then discussed from a multicriteria point of view. Finally, the extraction of the environmental database of the milk powder process from EcoInvent makes it possible to carry out sensitivity analyses, and suggest scenarios which are interesting both from economic and environmental viewpoints.

The composition of milk is of most importance to the dairy industry and human health. This study wasconducted to provide data on the composition of raw cow milk and artisanal yoghurt collected inMaroua (Cameroon). Milk and yoghurt samples were collected from 11 breeding sites and 12 producersin the city of Maroua, respectively. The following parameters were determined: pH, dry matter, ash, fat,lactose, total protein, non-casein nitrogen (NCN), non-protein nitrogen (NPN), true protein, wheyprotein, casein, amino acid composition, α-lactalbumin, β-lactoglobulin, αS1-casein, αS2-casein, β-casein, κ-casein and mineral composition. The results showed that, the composition of the milk andyoghurt varied from one sample to another. The chemical composition of some of the milk and yoghurtstudied differed from the corresponding samples in previous studies. For example the mean pH of theraw cow milk (6.25) and artisanal yoghurt (3.84) were lower. The mean NPN levels of the cow milk andyoghurt (0.21g/100g) were higher. The mean fat content of milk (4.48 g/100 g) was higher. The proteinfraction was lower in yoghurt while Fe, Cu and Mn levels were lower in both cow milk and yoghurt. Thedata reported in this paper would be helpful in dairy technology and public health.

absent

Food powders are materials that have been reduced to particulates. To achieve long term stability and usability, many liquid or solid food products and ingredients are dehydrated or mechanically converted into powder form. These days, drying is a ubiquitous unit operation in the food industry and has been successfully utilized by food technologists to develop several high-value products. Low moisture and water activity in food powder products no only enhances their shelf life but also provides ease of storage, handling, and transport. The editors and contributing chapter authors have compiled information about different processes involved in the production of food powders, their further processing, and the functional properties of these powders. This book intends to provide an updated review from established experts involved in both the powder food industry and academia.

The most frequently used technique for dehydration of dairy bacteria is freeze drying. Of the other possible preservation techniques used in the dairy industry to produce large amounts of dairy ingredients at commercially viable processing costs, spray drying is one of the main processing tools and the cost is 10 times lower than that of freeze drying. In this work, some examples are presented for different species of dairy bacteria with respect to spray-drying processes (as an alternative approach to freeze drying) and storage conditions for production of powdered bacterial cultures with high viability (100%) and count (1010 g−1). The advantages and disadvantages of this new approach (viability, contamination, yield during process and storage) are discussed.