La gélification thermique de protéines globulaires (albumine de sérum bovin (SAB) et β-Lactoglobuline) en mélange avec la pectine faiblement méthylée (pectine LM) a été étudiée par rhéologie et microscopie confocale à balayage laser couplée à une analyse d'image par la méthode de co-occurrences. Les propriétés des biopolymères seuls ont également été décrites. La différence entre le comportement des deux protéines globulaires en mélange a également été étudiée. La structure des gels de SAB, caractérisée par diffusion de la lumière, varie fortement selon la teneur en NaCl ou CaCl₂. Dans les mélanges, une compétition entre les cinétiques de gélification protéique et de séparation de phase est observée. Celle-ci est fortement dépendante des facteurs intrinsèques et extrinsèques du système, et en particulier de la teneur et la nature des sels ajoutés (NaCl et/ou CaCl₂). L'augmentation de concentration en pectine se traduit par une séparation de phase plus marquée. Selon les conditions de concentrations en biopolymères et la nature des sels dans le milieu, le gel de protéine est affaibli ou renforcé par la présence du polyoside. En présence de calcium, les deux biopolymères présentent une affinité spécifique pour ce cation qui se traduit, pour les pectines LM, par leur capacité à gélifier. En mélange, un gel composite est alors formé. Selon la teneur en NaCl, la gélification du mélange est gouvernée par celle des protéines ou celle des pectines LM. L'ensemble des résultats permet de proposer un schéma d'interprétation des mécanismes impliqués dans la formation des gels en mélange au cours du processus thermique basée sur la séparation de phase et la gélification des biopolymères.

This project considers the co-rotating twin screw extrusion of a confectionery paste comprising powdered proteins, sugars, water and fats. As is the case with many food industry products, this process has been developed experimentally with little quantitative understanding of how variations in processing conditions influence the formation of the extrudate. A variety of techniques have therefore been developed to characterise and quantify the dispersive mixing, distributive mixing and rheological flow properties of this complex, multiphase, viscoelastic, unstable material. These techniques have then been utilised in a pilot plant extruder study of the mechanics of mixing and paste formation during extrusion, considering the influence of both processing conditions and screw profile. The internal evolution of paste microstructure has been successfully tracked along the length of screw profile using dead-stop extractions of the screws. A rigorous off-line assessment of shear yield strength behaviour using cone penetrometry has shown the use of conventional off-line rheometers to be unviable due to rapid post extrusion hardening. This highlighted the need for an in-line rheological measurement technique for continuous extrusion analysis where the extruded material is severely time dependent and not extractable. In pursuit of this, a novel arrangement of bender elements is proposed and trialled, to rapidly characterise material parameters of viscoelastic pastes. A second technique looking to extend the application of shear wave interface reflection to multiphase pastes is also trialled. A novel analysis of thermogravimetric data (TGA) has generated a viable index of distributive mixing, suitable for use on complex multi-component materials where thermal decomposition temperatures of the components are not well defined. Quantitative image analysis of pastes using scanning electron microscopy (SEM), optical microscopy protein staining and a novel application of multiphoton microscopy (MPM) have been used to visualise paste microstructure and quantify dispersive mixing. From the pilot plant extruder study, the application of these techniques was successful in mapping the evolution of paste mixing and the resulting microstructure, as well as identifying key differences between pastes mixed by twin screw extrusion and batch mixing.

<p>Modeling microbial inactivation has a great influence on the optimization, control and design of food processes. In the area of food safety, modeling is a valuable tool for characterizing survival curves and for supporting food safety decisions. The modeling of microbial behavior is based on the premise that the response of the microbial population to the environment factors is reproducible. And that from the past, it is possible to predict how these microorganisms would respond in other similar environments. Thus, the use of mathematical models has become an attractive and relevant tool in the food industry.</p> <p>This research provides tools to relate the inactivation of microorganisms of public health importance with processing conditions used in nonisothermal and non-thermal food processing technologies. Current models employ simple approaches that do not capture the realistic behavior of microbial inactivation. This oversight brings a number of fundamental and practical issues, such as excessive or insufficient processing, which can result in quality problems (when foods are over-processed) or safety problems (when foods are under-processed). Given these issues, there is an urgent need to develop reliable models that accurately describe the inactivation of dangerous microbial cells under more realistic processing conditions and that take into account the variability on microbial population, for instance their resistance to lethal agents. To address this urgency, this dissertation focused on mathematical models, combined mathematical tools with microbiological science to develop models that, by resembling realistic and practical processing conditions, can provide a better estimation of the efficacy of food processes. The objective of the approach is to relate the processing conditions to microbial inactivation. The development of the modeling approach went through all the phases of a modeling cycle from planning, data collection, formulation of the model approach according to the data analysis, and validation of the model under different conditions than those that the approach was developed.</p> <p>A non-linear ordinary differential equation was used to describe the inactivation curves with the hypothesis that the momentary inactivation rate is not constant and depends on the instantaneous processing conditions. The inactivation rate was related to key process parameters to describe the inactivation kinetics under more realistic processing conditions. From the solution of the non-linear ordinary differential equation and the optimization algorithm, safety inferences in the microbial response can be retrieved, such as the critical lethal variable that increases microbial inactivation. For example, for nonisothermal processes such as microwave heating, time-temperature profiles were modeled and incorporated into the inactivation rate equation. The critical temperature required to increase the microbial inactivation was obtained from the optimization analysis. For non-thermal processes, such as cold plasma, the time-varying concentration of reactive gas species was incorporated into the inactivation rate equation. The approach allowed the estimation of the critical gas concentration above which microbial inactivation becomes effective. For Pulsed Electric Fields (PEF), the energy density is the integral parameter that groups the wide range of parameters of the PEF process, such as the electric field strength, the treatment time and the electrical conductivity of the sample. The literature has shown that all of these parameters impact microbial inactivation. It has been hyphothesized that the inactivation rate is a function of the energy density and that above a threshold value significant microbial inactivation begins. </p> <p>The differential equation was solved numerically using the Runge-Kutta method (<i>ode45</i> in MATLAB ®). The<i> lsqcurvefit</i> function in MATLAB ® estimated the kinetic parameters. The approach to model microbial inactivation, whether when samples were subjected to nonisothermal or to non-thermal food processes, was validated using data published in the literature and/or in other samples and treatment conditions. The modeling approaches developed by this dissertation are expected to assist the food industry in the development and validation process to achieve the level of microbial reduction required by regulatory agencies. In addition, it is expected to assist the food industry in managing food safety systems through support food safety decision-making, such as the designation of the minimal critical parameter that may increase microbial inactivation. Finally, this dissertation will contribute in depth to the field of food safety and engineering, with the ultimate outcome of having a broad and highly positive impact on human health by ensuring the consumption of safe food products.</p>

Les hydrocarbures aromatiques polycycliques (HAP) sont des contaminants de notre environnement et de notre alimentation. En raison de leur toxicité, la Commission européenne a réglementé leur teneur dans les denrées alimentaires et notamment dans les huiles. Les industriels des corps gras ont donc pour obligation de vérifier la conformité de leurs produits. Dans ce contexte, le groupe Lesieur souhaiterait développer un nouvel outil analytique rapide et portable. Ainsi, ce vaste projet de recherche vise à concevoir un microsystème électrophorétique capable d'analyser les HAP dans les huiles alimentaires. Première étude à s'inscrire dans ce projet, ce travail de thèse a donc consisté à développer de nouveaux protocoles analytiques. Dans une première partie, des méthodes de séparation des HAP ont été développées en électrophorèse capillaire (CE) modifiée par des cyclodextrines couplée à un détecteur de fluorescence induite par laser. En suivant des stratégies multivariées basées sur les plans d'expériences, deux méthodes de séparation ont été optimisées. Les huit HAP communs aux listes établies par l'agence de protection de l'environnement des Etats-Unis et l'agence européenne de sécurité sanitaire des aliments ont été séparés en moins de 7 min et dix-neuf HAP, également classés par ces deux organismes, ont été analysés en moins de 18 min. Ces méthodes de séparation ont été appliquées avec succès à des extraits d'huile dopés. Dans une deuxième partie, il a été question de transférer la méthode d'analyse des huit HAP au format microsystèmes. La principale difficulté rencontrée a été le manque de sensibilité du système de détection couplé aux puces. Le premier objectif a donc été d'optimiser les quantités d'échantillon injectées et les paramètres de la détection avec un composé modèle dans un tampon borate. Cependant, seulement quatre HAP sur les dix-neuf étudiés précédemment en CE ont pu être détectés. Toutefois, dans les conditions optimisées par le plan d'expériences, ils étaient séparés en moins de 4 min. Enfin, différents polymères à empreintes moléculaires (MIP) ont été synthétisés en vue d'extraire sélectivement les HAP des huiles. Après un criblage des conditions de synthèse, la sélectivité de chaque MIP a été évaluée en milieu pur en comparant sa capacité de rétention avec celle d'un polymère non-imprimé. Les huit HAP communs aux deux listes ont finalement pu être extraits sélectivement à partir d'huiles de tournesol, mais avec des rendements d'extraction encore insuffisants et qui nécessitent une amélioration de la procédure d'extraction.

Inledning: Baljväxter har flera miljö- och näringsmässiga fördelar och spås att bli framtidens föda. I Sverige finns det en värdefull kulturskatt som består av svenska baljväxter från förr som har samlats in av Programmet för odlad mångfald, POM. För att nå ut till konsumenter kan en sensorisk beskrivning vara en framkomlig väg som samtidigt ger ett mervärde för produkten och befrämjar en ökad konsumtion av baljväxter. Syfte: Syftet med detta examensarbete, inom ämnet mat och måltidskunskap, är att ta fram sensoriskt beskrivande ord för sex svenska baljväxter från förr. Examensarbetet ska sedan beskriva de utvalda svenska baljväxterna med hjälp av de framtagna sensoriskt beskrivande orden för att kunna presentera eventuella sensoriska skillnader. Material och metod: Sex olika sorters baljväxter ingick i undersökningen som bestod av en kvalitativ gruppdiskussion där sensoriskt beskrivande ord togs fram och ett andra steg en kvantitativ intensitetsbedömning av de olika sorterna. Båda undersökningarna gjordes av en expertpanel utvalda för sin kunskap om baljväxter. Resultat: De sensoriska ord som beskriver baljväxter är sötma, syrliga, beska, kastanj, nötig, smörig, frisk och fyllig smak samt med en varierande eftersmak. Munkänslan beskrivs med orden mjölig, krispig, fast och len. Intensitetsbedömningarna visade på små smakskillnader mellan baljväxterna men trots detta fanns särskiljande attribut för de sex olika baljväxtsorterna. Slutsats: De beskrivande sensoriska ord som detta examensarbete har utmynnat i kommer att hjälpa konsumenten att hitta rätt och öka mervärdet på produkterna. Samtidigt bevaras den svenska kulturskatten och konsumenten kan utveckla sin kulturella identitet tillsammans med alla de fördelaktiga egenskaper baljväxter besitter. / Introduction: Legumes have many favourable health and environmental benefits and are predicted to be the diet of the future. Sweden sits on a cultural treasure when it comes to legumes from the past that have been collected by The programme of cultivated diversity, POM. A sensory description would be a valuable tool to reach the consumer and a way to increase the consumption and value of the product. Purpose: The purpose of this thesis is to identify and bring forward sensory descriptive words for six Swedish legumes from the past. This thesis will also describe the Swedish legumes using the sensory descriptive words to evaluate whether there are sensory differences. Method: Six different types of legumes were used in the two surveys. The first survey consisted of a qualitative group discussion and the goal was to bring forward sensory descriptive words for the legumes. The second survey consisted of a quantitative intensity evaluation of the legumes. Both surveys were made by a panel of experts, chosen for their knowledge of legumes. Result: The sensory words which best describes the legumes are sweet, sour/acidic, bitter, chestnut, nutty, buttery, fresh, rich taste and with variations in aftertaste. The mouthfeel can be described as mealy, crisp, solid and tender. The evaluation of intensity proved the legumes to have few taste varieties, but despite the sensory descriptions each of the six legumes were possible to distinguish. Conclusion: The sensory descriptive words that this thesis have lead to can help the consumer to chose the right product, increase the value of the product an at the same time preserve a cultural treasure of Sweden. It is also possible for the consumer to create a cultural identity with all the good benefits that the legumes possess.

The era of the Internet has become increasingly important in our daily life. Internet channels are rapidly growing into sophisticated businesses. This thesis purpose is therefore to conduct an initial study on a newly approaching e-commerce business, namely the grocery basket business. As there has not yet been much research in this field the overall aim is to contribute to the research in this business area. There are many who argue that in relation to the Internet and e-commerce fields there are two other important fields: business model and supply chain. A qualitative approach is used, based on triangulation methodology including a multiple case study and a survey. The cases are two different types of e-commerce companies: brick-and-clicks and pure-players. An empirical investigation covering twenty interviews and a questionnaire with one thousand respondents has been conducted. Findings supported by the interviews and the questionnaire reveal much knowledge about the grocery basket business. This are analyzed in relation to literature of business model and supply chain and according to the two cases of companies in the business. The study concludes that there is a great deal of challenges facing the grocery basket business in both fields of business model and supply chain. In both cases it is a challenge to retain customers, flexibility for customers, competition and supply chain development. Regarding brick-and-clicks a major challenge is to make their physical channel and online channel work together. Regarding pure-players a major challenge is their dependency of wholesalers. In addition, recommendations to these acknowledged challenges are benchmarking on other successful grocery companies and/or other successful e-commerce companies. Additional recommendation for pure-players is that they should cooperate with a brick-and-mortar company. Finally, the study shows some decent potential in the business to reduce emissions. This by providing eco-friendly products with pre planned recipes to fit with the products, and having fewer products in stock.

Purpose: The purpose of this thesis is to investigate how food start-ups (FS) can make their primary food packaging (PFP) more eco-friendly by identifying and evaluating the performance of suited packaging alternative. The purpose was fulfilled by answering the three research questions:  RQ1) How to assess the eco-friendliness of PFP? RQ2) Which are areas of improvement in environmental performance? RQ3) What are the differences in performance across similar PFP’s?  Methods: To answer the research questions both the literature review and empirical data was required. The literature study was conducted to gather relevant theories about primary food packaging in food start-ups. To get the required empirical data, a single case study was conducted at a case company that suited the subject. The case study consisted of multiple interviews and document study. This enabled for an analysis in the form of pattern matching in order to answer the research questions and achieve the purpose.  Findings: The Study found that to assess the PFP that have direct impact on the environment the functional features and the environmental framework play a central role in the eco- friendliness of PFPs which analyzed the requirements for the PFP and a multi criteria decision making approach for the environmental assessment for the Green-PE. The stakeholder expectations were found by analyzing the criterion for the PFP. In addition, a comparison for an eco-friendlier alternative was analyzed with the current Green-PE to justify the performance for the PFP in FS.  Implications: The study results present practical implications with assessing the current Green-PE and evaluating the gaps for improvement areas, while also comparing similar PFP which is an eco-friendlier option for food packaging start-ups. As there has been no general theoretical implications, the findings of the thesis can be used as a basis for deeper insights into the subject through more extensive research.  Delimitations &amp; Scope: The focus was to identify and evaluate the current PFP environmental impact and not the other aspects of the life cycle assessment since the scope was limited. Also, a single case study was used rather than multiple case studies to analyze the eco-friendliness for PEPs.

No description available.

Single use plastic products (SUPs) are a primary cause of plastic pollution causing significant environmental harm. These products have little to no value after use and are challenging to recycle cost efficiently. In a bid to combat this issue and foster circular economy, the European Union has declared a series of directives to gradually phase out SUPs as a strategy to eliminate these disposables from the market. This approach allows the market time to discover alternative solutions to replace SUPs, promoting the adoption of reusable products. To make a sustainable system of reusable products feasible and profitable, the key lies in devising a business model designed for a circular strategy of repeated use of goods. One effective approach involves establishing a closed-loop supply chain (CLSC) which entails the entire life cycle of a product, from sourcing raw materials, through manufacturing, utilisation, collection, reverse logistics and recycling. The purpose of this study was to develop a CLSC system for reusable plastic products between a plastic producing small or medium sized enterprise (SME) and an incumbent firm customer to attain a smooth transition from linear to circular economy. Employing an inductive approach, this case study considered the EU-directives as observational data, the change of business model as the result, and a general recommendation as the rule. The research method encompassed conducted interviews, mathematical prototyping, product design, and life cycle analysis, using various tools and methods in the process. Two case companies were involved: one large incumbent firm and one plastic producing SME. The aim was to design a circular business model (CBM) to capture the value of the collaboration between these two companies. After an analysation of the current situation, the main obstacles to a successful transition were identified. A comprehensive solution was developed, including a network of partners for the CLSC, a reusable product design, and the necessary implementation calculations. The finalised business model was anchored in the principles of the CLSC, the product design specifications and the calculations that determined the system’s viability. Implementation of the CBM would yield economic advantages for both stakeholders, as well as an improved green image factor and advancement in circular economy. Furthermore, this transition would cultivate valuable and lasting business relationships for both companies. These case findings harmonise with established theories which emphasise the significance of business models that are dependent on collaboration and long-term strategic planning. Lastly, they also underscore that value is created in product utilisation and not ownership.

Food packaging should ensure the safety and quality of food, minimize spoilage and provide an easy way of storing and handling it. Barrier coatings are generally used to meet the demands placed on fibre-based food packages, as these have the ability to regulate the amount of gases that can enter them. Some gases are detrimental to food quality: oxygen, for example, initiates lipid oxidation in fatty foods. Using both experimental data and computer modelling, this thesis explains some aspects of how the structure of barrier coatings influences the mass transport of oxygen with the aim of obtaining essential knowledge that can be used to optimize the performance of barriers. Barrier coatings are produced from polyvinyl alcohol and kaolin blends that are coated onto a polymeric support. The chemical and physical structures of these barriers were characterized according to their influence on permeability in various climates. At a low concentration of kaolin, the crystallinity of polyvinyl alcohol decreased; in the thinner films, the kaolin particles were orientated in the basal plane of the barrier coating. The experimental results indicated a complex interplay between the polymer and the filler with respect to permeability. A computer model for permeability incorporating theories for the filled polymeric layer to include the polymer crystallinity, addition of filler, filler aspect ratio and surrounding moisture was developed. The model shows that mass transport was affected by the aspect ratio of the clay in combination with the clay concentration, as well as the polymer crystallinity. The combined model agreed with the experiments, showing that it is possible to combine different theories into one model that can be used to predict the mass transport. Four barrier coatings: polyethylene, ethylene vinyl alcohol + kaolin, latex + kaolin and starch were evaluated using the parameters of greenhouse gas emissions and product costs. After the production of the barrier material, the coating process and the end-of-life handling scenarios were analysed, it emerged that starch had the lowest environmental impact and latex + kaolin had the highest. / Food packaging is required to secure the safety and quality of food, as well as minimize spoilage and simplify handling. Barrier coatings are generally used to meet the demands placed on fibre-based food packages, as these have the ability to regulate the amount of gases that can enter them. Some gases are detrimental to food quality: oxygen, for example, initiates lipid oxidation in fatty foods. This thesis focuses on the mass transport of oxygen in order to gain deeper knowledge of, and thereby optimise, the performance of barrier coatings. This experimental study, together with computer modelling, characterized the structure of barrier materials with respect to the mass transport process. The performance of the barriers was evaluated based on the parameters of environmental impact and product costs. As the long-term aim is to use non-petroleum-based barrier coatings for packaging, these should be evaluated by assessing the properties of the material in question, its functionality and its environmental impact to provide more insight into which materials are desirable as well as to develop technology. The results from this study indicate that several parameters (the orientation, concentration and aspect ratio of the clay and the polymer crystallinity) influence the properties of a barrier. Using this knowledge, researchers and food packaging engineers can work toward improving and customising renewable barriers. / VIPP