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  • 1.
    Bolinsson, Hans
    et al.
    Lund University.
    La, Yi
    Lund University.
    Hall, Stephen
    Lund University.
    Nilsson, Lars
    Lund University.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    A novel method for calibration of AF4 channels for hydrodynamic radius determination: the nanoemulsion method (featuring MALS)2018In: Journal of Chromatography A, ISSN 0021-9673, Vol. 1533, p. 155-163Article in journal (Refereed)
    Abstract [en]

    This study suggests a novel method for determination of the channel height in asymmetrical flow field-flow fractionation (AF4), which can be used for calibration of the channel for hydrodynamic radiusdeterminations. The novel method uses an oil-in-water nanoemulsion together with multi angle lightscattering (MALS) and elution theory to determine channel height from an AF4 experiment. The methodis validated using two orthogonal methods; first, by using standard particle elution experiments and, sec-ondly, by imaging an assembled and carrier liquid filled channel by x-ray computed tomography (XCT). It is concluded that the channel height can be determined with approximately the same accuracy aswith the traditional channel height determination technique. However, the nanoemulsion method canbe used under more challenging conditions than standard particles, as the nanoemulsion remains stablein a wider pH range than the previously used standard particles. Moreover, the novel method is also morecost effective.

  • 2. Brinkmann, Philipp
    et al.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen. Kristianstad University, Resrarch environment Food and Meals in Everyday Life (MEAL).
    Būtienė, Indrė
    Kjærsgard, Hanne
    Kofoed Mortensen, Birthe
    Martens, Janet
    Müller-Hansen, Bitte
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen.
    Petrenko, Anton
    The use of networks as a strategic approach of micro-enterprises in the agri-food sector2014In: International Journal of Entrepreneurship and Innovation, ISSN 1465-7503, E-ISSN 2043-6882, Vol. 15, no 3, p. 169-178Article in journal (Refereed)
    Abstract [en]

    Increasing competition and regulatory changes place micro-sized enterprises (MSEs) in the agri-food sector under strong competitive pressure. Smallness may be a substantial barrier to success. Previous research suggests that networks can be used strategically to combat these constraints. However, there is a lack of understanding of the extent to which this finding may be applicable to MSEs and the local agri-food sector. Based on eight in-depth interviews of agri-food MSEs, it is concluded that MSEs apply networks to strengthen their competitive advantage – for example, by forming stronger customer relationships. The MSEs are using their networks to combat their size-related disadvantages, but not by growing; rather, the networks enable them to remain small and independent while further strengthening their position as small producers.

  • 3. De Carvalho, Irene Stuart Torrié
    et al.
    Granfeldt, Yvonne
    Dejmek, Petr
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen.
    From diets to foods: using linear programming to formulate a nutritious, minimum-cost porridge mix for children aged 1 to 2 years2015In: Food and Nutrition Bulletin, ISSN 0379-5721, E-ISSN 1564-8265, Vol. 36, no 1, p. 75-86Article in journal (Refereed)
    Abstract [en]

    Background. Linear programming has been used extensively as a tool for nutritional recommendations. Extending the methodology to food formulation presents new challenges, since not all combinations of nutritious ingredients will produce an acceptable food. Furthermore, it would help in implementation and in ensuring the feasibility of the suggested recommendations.

    Objective. To extend the previously used linear programming methodology from diet optimization to food formulation using consistency constraints. In addition, to exemplify usability using the case of a porridge mix formulation for emergency situations in rural Mozambique.

    Methods. The linear programming method was extended with a consistency constraint based on previously published empirical studies on swelling of starch in soft porridges. The new method was exemplified using the formulation of a nutritious, minimum-cost porridge mix for children aged 1 to 2 years for use as a complete relief food, based primarily on local ingredients, in rural Mozambique.

    Results. A nutritious porridge fulfilling the consistency constraints was found; however, the minimum cost was unfeasible with local ingredients only. This illustrates the challenges in formulating nutritious yet economically feasible foods from local ingredients. The high cost was caused by the high cost of mineral-rich foods. A nutritious, low-cost porridge that fulfills the consistency constraints was obtained by including supplements of zinc and calcium salts as ingredients.

    Conclusions. The optimizations were successful in fulfilling all constraints and provided a feasible porridge, showing that the extended constrained linear programming methodology provides a systematic tool for designing nutritious foods. 

  • 4.
    Gerberich, Johanna
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Olsson, Viktoria
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Humaniora.
    Müller- Hansen, Bitte
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Höijer, Karin
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Wendin, Karin
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Promoting creativity in Food and Meal Science educations at Kristianstad University2016Conference paper (Other academic)
  • 5. Glantz, Maria
    et al.
    Håkansson, Andreas
    Lunds universitet.
    Lindmark Månsson, Helena
    Paulsson, Marie
    Nilsson, Lars
    Revealing the Size, Conformation, and Shape of Casein Micelles and Aggregates with Asymmetrical Flow Field-Flow Fractionation and Multiangle Light Scattering2010In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 15, p. 12585-12591Article in journal (Refereed)
    Abstract [en]

    Casein (CN) micelles are naturally occurring colloidal protein aggregates present in a dispersed state in milk. In this paper we aim to obtain a detailed description of physicochemical properties of CN micelles over the entire size distribution using asymmetrical flow field-flow fractionation (AsFlFFF) connected to multiangle light scattering (MALS) and refractive index (RI) detection. Conclusions are drawn on the colloidal level regarding shape and conformation by comparison with models of colloidal particles. By using AsFlFFF-MALS-RI, it is concluded that the CN micelles are highly polydisperse with an average rms radius and hydrodynamic radius of 177 and 116 nm, respectively. The results show that the majority of CN micelles have a spherical shape, whereas a low concentration exists of larger and elongated aggregates. By comparison with models of aggregates of colloidal particles, the aggregates are shown to be anisotropic, e.g., aggregating linearly (threadlike) or in a sheet, rather than forming randomly spherical clusters. The results show that the characterization of colloidal dispersions with AsFlFFF-MALS-RI and the comparison with theoretical models are of a general character and, thus, of fundamental importance for colloidal dispersions.

  • 6.
    Hakansson, Andreas
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap.
    Askaner, Måns
    Kristianstad University.
    Innings, Fredrik
    Tetra Pak, Lund.
    Extent and mechanism of coalescence in rotor-stator mixer food-emulsion emulsification2016In: Journal of Food Engineering, ISSN 0260-8774, E-ISSN 1873-5770, Vol. 175, p. 127-135Article in journal (Refereed)
    Abstract [en]

    Food-emulsions often have high volume fractions of dispersed phase and are thus expected to show coalescence during emulsification, however, food-emulsion coalescence is difficult to measure in homogenizer equipment. This study experimentally estimates the rates of fragmentation and coalescence in a high viscosity and high volume fraction model emulsion subjected to pilot-scale rotor-stator mixing in order to quantify the relative effect of coalescence and discuss the mechanism of coalescence during batch processing of high-fat emulsion foods. Rate constants of both processes are estimated using a previously suggested method relying on parameter fitting from the dynamic evolution of the total number of emulsion drops (Hounslow and Ni, 2004). The results show substantial coalescence taking place. Scaling of rates with respect to rotor tip speed suggests coalescence and fragmentation controlled by a turbulent viscous mechanism. (C) 2015 Elsevier Ltd. All rights reserved.

  • 7.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    An experimental investigation of the probability distribution of turbulent fragmenting stresses in a high-pressure homogenizer2018In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 177, p. 139-150Article in journal (Refereed)
    Abstract [en]

    The high-pressure homogenizer (HPH) is, together with the rotor–stator mixer (RSM), the standard equipment for emulsification in many fields of chemical processing. Both give rise to intense turbulence which, in turn, gives rise to drop breakup. Previous investigations focus on average turbulent disruptive stress. However, turbulence is a stochastic phenomenon and drop breakup will be characterized by instantaneous stresses, or more specifically by the probability distribution of instantaneous turbulent stresses.

    This study uses high-resolution particle image velocimetry (PIV) data to measure the probability distribution of turbulent stresses in the HPH. It is concluded that stress distributions approximately follow a lognormal model and that the skewness of the distributions decreases with increasing distance from the gap exit until a constant distribution shape is obtained at the position where the turbulence is fully developed. This converged stress distribution is similar to that obtained for RSMs in previous studies, suggesting that stress distribution shape is a general property. Moreover, large differences are observed when comparing these experimental stress distributions to the most widely used expression for describing this stochastic effect in fragmentation rate models. This indicates that the traditionally used fragmentation rate models can be fundamentally flawed, at least in relation to RSM and HPH emulsification.

  • 8.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Are food advertisements promoting more unhealthy foods and beverages over time?: evidence from three Swedish food magazines, 1995-20142017In: Ecology of Food and Nutrition, ISSN 0367-0244, E-ISSN 1543-5237, Vol. 56, no 1, p. 45-61Article in journal (Refereed)
    Abstract [en]

    Unhealthy food in advertising has been suggested as a mediator for the increase in diet-related illness. This study quantitatively investigates changes in food advertising between 1995 and 2014 in terms of food categories promoted, macronutrient content, and percentage of foods classified as heathy or unhealthy from a sample of 7,199 ads from three Swedish food magazines. With the exception of increased alcoholic beverage and decreased carbohydrate-rich-food promotion, no monotonic trends of increasingly unhealthy food advertisement are found. From these findings, it is argued that food magazine advertising is not a mediator of the adverse dietary trend.

  • 9.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap.
    Assessing and evolving the progress plan in quantitative thinking for the bachelor program in culinary arts and food science2014In: Lärarlärdom: högskolepedagogisk konferens 2014 / [ed] Christina Hansson, Karlskrona: Blekinge Tekniska Högskola, 2014, p. 113-133Conference paper (Other academic)
    Abstract [en]

    The objectives of the study were, first, to assess the progression in quantitative thinking between first-, second-, and third-year students enrolled in the Bachelor in Culinary Arts and Food Science program and, second, to use the insight to suggest necessary changes to the curriculum to ensure better progression.

    A standardized quantitative test was used to measure progression in functional knowledge divided in four categories: (i) calculation skills and basic mathematics, (ii) application and interpretation of descriptive statistics, (iii) interpretation of analytical statistics, and (iv) communication through graphs and charts.

    The results show significant progression in skills and confidence across study years. Broken down into the four categories, progression is stronger in statistics (categories ii–iii). The most problematic category is basic calculations, where the average score is low and progress across study years is poor.

    A suggestion is presented for how to reform the curriculum in order to improve progression in basic calculation by emulating the methods used for teaching statistics, where progression is better. 

  • 10.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, Faculty of Natural Science, Avdelningen för mat- och måltidsvetenskap.
    Det ängsliga matsamhället2018Book (Other academic)
    Abstract [sv]

    Allt mer av det vi stoppar i oss har vid något tillfälle befunnit sig i fabrikernas rostfria ståltankar, transporterats på löpande band, behandlats med kemiskt framtagna tillsatser och förpackats i färgglada förpackningar. Istället för gladlynta kockar eller känsliga mathantverkare är det idag kemister, ingenjörer och industriarbetare som designar, tillverkar och monterar vår mat.

    Men många som köper den industriellt producerade maten är samtidigt oroliga och känner dåligt samvete. Och många högröstade kritiker menar att industrimaten är näringsfattig, miljöfarlig, bedräglig – eller rentav giftig. Finns det fog för denna kritik?

    Det ängsliga matsamhället tittar närmare på den industriella matproduktionen och drar slutsatsen att industrimat inte alls är så farlig som många tror. Kritiken bygger snarare på att den storskaliga industriella matproduktionen har hamnat på kollisionskurs med en samling vanliga värderingar, som exempelvis uppfattningen att det som producerats utan mänsklig inblandning alltid är bättre (biofili) eller att den traditionella maten automatiskt är bättre bara i egenskap av sin historia (mat-konservatism). Att kritisera färdigmat och pulversås har dessutom blivit ett sätt att markera sin egen moraliska förträfflighet och klasstillhörighet. Vi ser också att motståndet har blivit en kraftfull och samlande symbol för sådant många debattörer vänder sig emot – d­et är egentligen inte ett motstånd mot en viss sorts mat så mycket som mot teknokrati, liberalism, marknadsekonomi och rationalism.

  • 11.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen.
    Droplet breakup in high-pressure homogenizers2015In: Engineering aspects of food emulsification and homogenization / [ed] Marilyn Rayner and Petr Dejmek, Boca Raton: Taylor & Francis Group, 2015, p. 125-148Chapter in book (Other academic)
    Abstract [en]

    In this chapter, a detailed review of the current understanding of the physical processes of droplet breakup in a high-pressure homogenizer (HPH) is presented, covering breakup mechanisms by laminar shear in the gap inlet and its boundary layers, by local turbulence in the gap exit jet, and by cavitation. Experimental evidence of the effetcts of homogenization pressure, Thoma number, dispersed and continuous phase viscosity, and dispersed phase volume fraction in relation to implications on dominant mechanisms of droplet breakup is also discussed.

  • 12.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Experimental methods for measuring coalescence during emulsification: a critical review2016In: Journal of Food Engineering, ISSN 0260-8774, E-ISSN 1873-5770, Vol. 178, p. 47-59Article, review/survey (Refereed)
    Abstract [en]

    Emulsification is a common process in the production in many non-solid foods. These food-emulsions often have high disperse phase volume fractions and slow emulsifier dynamics, giving rise to substantial coalescence during emulsification. Optimal design and operation of food-emulsification requires experimental methods to study how emulsification in general and coalescence in particular progresses under different conditions. Methods for coalescence quantification during emulsification has been suggested in literature but they are rarely used in food-emulsification research. This contribution offers a critical review of the different methods that have been suggested with special emphasis on their applicability to technical food-emulsification. The methods are critically compared in terms of design limitations, degree of quantification and applicability. A state-of-the-art in the form of two methods is identified and guidelines for their application are suggested. (C) 2016 Elsevier Ltd. All rights reserved.

  • 13.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, Faculty of Natural Science, Avdelningen för mat- och måltidsvetenskap.
    Fabrication of nanoemulsions by high-pressure valve homogenization2018In: Nanoemulsions: formulation, applications, and characterization / [ed] Seid Mahdi Jafari and David Julian McClements, Elsevier, 2018, p. 175-206Chapter in book (Other academic)
    Abstract [en]

    High-pressure valve homogenization is a standard technique for nanoemulsion formation in low-viscosity formulations. It is applied extensively in industrial applications and in academic research. This chapter summarizes the scientific-based knowledge in terms of principal mechanisms of operation and practical applicability of the methodology. It is concluded that high-pressure valve homogenization has many advantages in producing nanoemulsions; the technique is mature and allows for continuous production and for production in various scales. However, the technique also has limitations. The thermodynamic efficiency is low, giving rise to high energy cost, and a substantial temperature rises in the product. The high pressures required for nanoemulsion formation have also been reported to cause overprocessing, which results in an additional limitation.

  • 14.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen.
    Has it become increasingly expensive to follow a nutritious diet?: Insights from a new price index for nutritious diets in Sweden 1980-20122015In: Food & Nutrition Research, ISSN 1654-6628, E-ISSN 1654-661X, Vol. 59, article id 26932Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Health-related illnesses such as obesity and diabetes continue to increase, particularly in groups of low socioeconomic status. The increasing cost of nutritious food has been suggested as an explanation.

    OBJECTIVE: To construct a price index describing the cost of a diet adhering to nutritional recommendations for a rational and knowledgeable consumer and, furthermore, to investigate which nutrients have become more expensive to obtain over time.

    METHODS: Linear programming and goal programming were used to calculate two optimal and nutritious diets for each year in the interval under different assumptions. The first model describes the rational choice of a cost-minimizing consumer; the second, the choice of a consumer trying to deviate as little as possible from average consumption. Shadow price analysis was used to investigate how nutrients contribute to the diet cost.

    RESULTS: The cost of a diet adhering to nutritional recommendations has not increased more than general food prices in Sweden between 1980 and 2012. However, following nutrient recommendations increases the diet cost even for a rational consumer, particularly for vitamin D, iron, and selenium. The cost of adhering to the vitamin D recommendation has increased faster than the general food prices.

    CONCLUSIONS: Not adhering to recommendations (especially those for vitamin D) offers an opportunity for consumers to lower the diet cost. However, the cost of nutritious diets has not increased more than the cost of food in general between 1980 and 2012 in Sweden.

  • 15.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Indoctrination or education?: intention of unqualified teachers to transfer consumption norms in home economics teaching2015In: International Journal of Consumer Studies, ISSN 1470-6423, E-ISSN 1470-6431, Vol. 39, no 6, p. 682-691Article in journal (Refereed)
    Abstract [en]

    Almost two thirds of home economics teachers in Sweden are formally unqualified. Historically, home economics has focused more on fostering and prescribing the “right” choices whereas the modern (2011-) curriculum focuses on teaching consequences of choices and giving students tools for assessing alternatives. Restraining from prescribing norms requires a high degree of professionalism. The objective of this study was to empirically investigate the prevalence of intentions of formally unqualified teachers to prescribe consumption norms not supported by the curriculum. Furthermore, to investigate to what extent these intentions are correlated with years of experience as a teacher, personal preferences, or personal consumption. The intention to transfer norms were measured using the concept of intentional misalignment applied to a survey distributed to a sample of formally unqualified teachers attending complementary teacher education. A two part survey was used. The first part consisted of multiple choice questions asking the teachers how important they saw it to transfer different consumption norms to their students (e.g. to consume local or organic food). These responses were evaluated quantitatively (Spearman rank correlation, Wilcoxon rank sum test and Kruskal-Wallis analysis of variance). The second part consisted of an open-ended question asking teachers to describe what they saw as the most important take-home message for students in home economics. The answers were compared to the national curriculum to identify intentions to transfer unsupported norms. The study indicates that more than a third of the formally unqualified home economics teachers in Sweden express the intention to prescribe specific types of consumption or to transfer consumption norms that are not supported by the curriculum. The prevalence is correlated to personal preferences and thus indicates difficulties with keeping a professional perspective. These teachers must be given collegial support and opportunities for continued education – to ensure high-quality home economics education for future generations.

  • 16.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Intentions of formally qualified and unqualified teachers to transfer norms and values in home economics teaching2016In: International Journal of Consumer Studies, ISSN 1470-6423, E-ISSN 1470-6431, Vol. 40, no 3, p. 268-275Article in journal (Refereed)
    Abstract [en]

    Historically, home economics in general, and the consumer education sections in particular, have been criticized for transferring norms and values of conservative elites to the masses. This is in stark contrast to contemporary theoretical views of a modern home economics aimed at educating emancipated and critical citizens, and also to modern curricula that emphasize the consequences of consumption rather than dogma. A previous study has indicated that formally unqualified teachers see the transfer of consumption norms and values without support in the curriculum as an important objective of home economics teaching, a practice that is questionable from a democratic perspective. This follow-up study investigates to what extent formally qualified home economics teachers show intentions to transfer consumption norms and values without support in the curriculum to students, by using content analysis of 201 survey responses from Swedish qualified home economics teachers and comparing to data from a previously published study on formally unqualified teachers. It is concluded that the qualified teachers demonstrate intentions to transfer unsupported norms and values, though, to a lower degree than unqualified teachers. The results are interpreted by adopting a values education perspective on home economics. This indicates that the observed emphasis on norms and values could be seen partly as a lack of a proficient professional metalanguage among the teachers, and partly as a consequence of the focus on developing a pre-defined moral of consumption in home economics literature. The implications on how to develop home economics teacher education to reduce norm and value transfer intentions are discussed based on the empirical findings and the theoretical framework. This article is protected by copyright. All rights reserved.

  • 17.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap.
    Local food and industrial large scale production2015In: Interdisciplinary perspectives on local and regional food in the South Baltic Region / [ed] Anton Petrenko and Bitte Müller-Hansen, Kristianstad: Kristianstad University Press , 2015, p. 157-165Chapter in book (Other academic)
    Abstract [en]

    Many local and regional food consumers state their intention to support local communities as the motivation behind buying local or regional food. This chapter compares this view to an economic perspective of what creates value and prosperity in a community. The economic perspective is generally less optimistic of the benefits of local or small scale production. However, as seen towards the end of the chapter, local and regional food producers still have an important role to play on the food market by adopting suitable strategies.

  • 18.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Professor: därför är skatt på socker fel väg2017In: Svenska dagbladet, ISSN 1101-2412, no 31 januariArticle in journal (Other (popular science, discussion, etc.))
  • 19.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, Faculty of Natural Science, Avdelningen för mat- och måltidsvetenskap. Lund University.
    Rotor-stator mixers: from batch to continuous Mode of Operation—a review2018In: Processes, ISSN 2227-9717, E-ISSN 1099-5862, Vol. 6, no 32Article in journal (Refereed)
    Abstract [en]

    Although continuous production processes are often desired, many processing industriesstill work in batch mode due to technical limitations. Transitioning to continuous production requires an in-depth understanding of how each unit operation is affected by the shift. This contribution reviews the scientific understanding of similarities and differences between emulsification in turbulent rotor-stator mixers (also known as high-speed mixers) operated in batch and continuous mode. Rotor-stator mixers are found in many chemical processing industries, and are considered the standard tool for mixing and emulsification of high viscosity products. Since the same rotor-stator heads are often used in both modes of operation, it is sometimes assumed that transitioning from batch to continuous rotor-stator mixers is straight-forward. However, this is not always the case, as has been shown in comparative experimental studies. This review summarizes and critically compares the current understanding of differences between these two operating modes, focusing on shaft power draw, pumping power, efficiency in producing a narrow region of high intensity turbulence, and implications for product quality differences when transitioning from batch to continuousrotor-stator mixers.

  • 20.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Scale-down failed: dissimilarities between high-pressure-homogenizers of different scales due to failed mechanistic matching2017In: Journal of Food Engineering, ISSN 0260-8774, E-ISSN 1873-5770, Vol. 195, p. 31-39Article in journal (Refereed)
    Abstract [en]

    The high-pressure homogenizer (HPH) is used extensively in the processing of non-solid foods. Food researchers and producers use HPHs of different scales, from laboratory-scale (∼10 L/h) to the largest production-scale machines (∼50 000 L/h). Hence, the process design and interpretation of academic findings regarding industrial condition requires an understanding of differences between scales. This contribution uses theoretical calculations to compare the hydrodynamics of the different scales and interpret differences in the mechanism of drop-breakup.

    Results indicate substantial differences between HPHs of different scales. The laboratory-scale HPH operates in the laminar regime whereas the production-scale is in the fully turbulent regime. The smaller scale machines are also less prone to cavitation and differ in their pressure profiles. This suggest that the HPHs of different scales should be seen as principally different emulsification processes. Conclusions on the effect or functionality of a HPH can therefore not readily be translate between scales.

  • 21.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap.
    Utgör livsmedelspriser en barriär mot en hälsosam kost?2015In: Ekonomisk Debatt, Vol. 43, no 7, p. 22-33Article in journal (Other academic)
  • 22.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Vad ska vi med föreläsningar till?2017In: Högre Utbildning, ISSN 2000-7558, E-ISSN 2000-7558, Vol. 7, no 2, p. 40-50Article in journal (Refereed)
    Abstract [sv]

    Föreläsningen är en märklig undervisningsform. Samtidigt som den är den vanligast förekom-mande metoden, är den också den mest föraktade. Det finns gott om högskolepedagogisk litteratur som förklarar varför föreläsningen är olämplig för att stimulera lärande. Ändå fortsätter vi föreläsa. Det kan tyckas motsägelsefullt. Denna reflektion vänder på frågan och letar efter föreläsningens fördelar. Utifrån tre öppet tillgängliga föreläsningsserier föreslås tre fördelar med föreläsningen som undervisningsform, fördelar som ofta hamnat i skymundan. De föreslagna fördelarna är: föreläsningar kan genom goda nytolkningar och omformuleringar underlätta inlärningen, den kan ge grund och struktur till nya ämnesområden, och den kan introducera studenter till vad som avses med reflektion på en akademisk nivå. Slutsatsen är inte att alla föreläsningar nödvändigtvis alltid är motiverade, utan att vi med rätt kunskap och inställning kan föreläsa bättre. Uppenbarligen är det mycket lätt att föreläsa på ett sådant sätt att lärande inte främjas. Men det innebär inte att undervisningsmetoden som sådan är alltigenom oanvändbar. I ljuset av reflektionens tre exempel diskuteras också vad vi kan göra för att föreläsa bättre och vilka implikationer detta har för lärare involverade i högreutbildning.

  • 23.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen. Kristianstad University, Resrarch environment Food and Meals in Everyday Life (MEAL).
    What is overconsumption?: a step towards a common understanding2014In: International Journal of Consumer Studies, ISSN 1470-6423, E-ISSN 1470-6431, Vol. 38, no 6, p. 692-700Article in journal (Refereed)
    Abstract [en]

    Overconsumption is a widely used term in science, media and among concerned consumers. What do we mean by this term? This study is based on the assumption that both the public debate on consumption and consumer research could benefit from better understanding how this term is used and from clarifying the definition. The primary aim of this study was to describe how the term ‘overconsumption’ is being used in the contemporary scientific debate in fields related to consumer studies. This was done by studying the use of the term in scientific journal papers between 2010 and 2012 using qualitative content analysis. It is concluded that overconsumption is often described as consumption of hedonic goods by individuals with undesirable personality traits, low moral or belonging to minority groups. Furthermore, overconsumption is described as having detrimental effects both on the individual consumer, the society and the environment; however, direct individual effects are more frequently mentioned in the studies. The term is seldom defined explicitly. This might lead to confusion and misunderstanding between research fields and between different stakeholders. A structured framework for generating clear and useful definitions is suggested in this study, based on the reviewed papers and a theoretical framework from moral philosophy.

  • 24.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap.
    What makes local food attractive to consumers?2015In: Interdisciplinary perspectives on local and regional food in the South Baltic Region / [ed] Anton Petrenko and Bitte Müller-Hansen, Kristianstad: Kristianstad University Press , 2015, p. 85-93Chapter in book (Other academic)
    Abstract [en]

    In order to understand the potential of local and regional food, we must first understand what it is about these goods that attract consumers. This chapter summarizes the research on what drives local food consumption, starting from an overview of the motivations of the consumers themselves and different descriptions of what characterizes consumers of local food (“locavore“), and continuing with potential explanations for underlying motives.

  • 25.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen.
    Även utan arbetstidsförkortning fortsätter vår fritid att öka2014In: Ekonomisk Debatt, ISSN 0345-2646, Vol. 42, no 3, p. 83-87Article in journal (Other (popular science, discussion, etc.))
  • 26.
    Håkansson, Andreas
    et al.
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap.
    Andersson, Håkan
    Linnaeus University.
    Granfeldt, Yvonne
    Lund University.
    Diet inequality prevails among consumers interested andknowledgeable in nutrition2015In: Food & Nutrition Research, article id 27601Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Previous studies have demonstrated a correlation between diet cost and adherence to nutritional recommendations among consumers in general. This has adverse effects on diet and health inequality. It could be hypothesized that consumers knowledgeable in nutrition escape this correlation.

    OBJECTIVE:

    Investigate whether the previously observed relationship between diet cost and nutritional quality prevails among consumers with an above-average interest in and knowledge of nutrition.

    DESIGN:

    Full open diet registrations of 330 students taking a basic university-level course in nutrition over a total of 780 days.

    RESULTS:

    The consumers with the highest daily average diet cost differ from the lowest cost quartile: The diets had higher micronutrient density, more fruits and vegetables, and lower energy density. The highest cost daily diet quartile had a significantly higher energy adjusted intake of the micronutrients that were on average consumed below the recommendation (vitamin D, folate, and iron for women). On the other hand, alcohol intake was significantly higher among the high diet cost group. The highest diet cost respondents consumed more fish, meat, coffee, and spreads, whereas the lowest diet cost respondents had a higher consumption of cereals, bread, jam, sausage, and milk.

    CONCLUSIONS:

    Dietary differences prevail even in the above-average interested and knowledgeable group. The respondents did not use their higher level of knowledge to break this commonly observed relationship. This suggests that an increased minimum level of knowledge in nutrition may not by itself eliminate dietary inequality.

  • 27.
    Håkansson, Andreas
    et al.
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Andersson, Ronnie
    Chalmers University.
    Mortensen, Hans-Henrik
    Tetra Pak .
    Innings, Fredrik
    Tetra Pak .
    Experimental investigations of turbulent fragmenting stresses in a rotor-stator mixer. Part 2: probability distributions of instantaneous stresses2017In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 171, p. 638-649Article in journal (Refereed)
    Abstract [en]

    Drop fragmentation in high intensity turbulent emulsification processing equipment-such as rotor-stator mixers (RSMs)-has traditionally been described in terms of a stress balance; between the stabilizing stress of the drop and the time-averaged turbulent stress at the most intense position of the flow. As shown in part 1 of this series, this approach is often a fruitful first approximation. However, the instantaneous local stress experienced by drops differs,from the time-averaged local stress due to hydrodynamics in general and the stochastic nature of a turbulent flow in particular. This study estimates the probability distribution of instantaneous turbulent stresses in an RSM from velocity fields obtained using particle image velocimetry. Results show that regions with low average stress still have a substantial probability of having instantaneously high stresses. This explains why low probability breakup is observed at these positions in visualization experiments. Results also show that the probability distribution of instantaneous stresses is approximately lognormal. The results are compared to two commonly used models for how to take the stochastic variations into account: the exponential decay model, and the multifractal emulsification model. It is concluded that both models predict reasonable distributions shapes but underestimate the width of the stress distribution.

  • 28.
    Håkansson, Andreas
    et al.
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Arlov, Dragana
    Tetra Pak Proc Syst AB.
    Carlsson, Fredrik
    FS Dynam AB.
    Innings, Fredrik
    Tetra Pak Proc Syst AB & Lund University .
    Hydrodynamic difference between inline and batch operation of a rotor-stator mixer head: a CFD approach2017In: Canadian Journal of Chemical Engineering, ISSN 0008-4034, E-ISSN 1939-019X, Vol. 95, no 4, p. 806-816Article in journal (Refereed)
    Abstract [en]

    Rotor-stator mixers (RSMs) can be operated in either batch or inline mode. When operating a rotor-stator geometry in batch mode, it typically experiences an order of magnitude higher volumetric flow through the stator than in inline mode. This is expected to cause differences in the flow and turbulence in the rotor-stator region. This study uses computational fluid dynamics (CFD) to study the hydrodynamic differences in and near the stator hole as a function of volumetric flow rates between those experienced in inline and batch modes of operation. It is concluded that both radial flow profiles and turbulent kinetic energy across a range of rotor speeds and flow rates can be described by a velocity ratio: average tangential fluid velocity in the stator hole divided by the rotor tip speed. Moreover, the position where dissipation of turbulent kinetic energy takes place-and hence the effective region of dispersion or mixing-differs between the two modes of operation. The relative importance of the two regions can be described in terms of the velocity ratio and the transition can be predicted based on the relative power input due to rotational and pumping power of the mixer. This study provides a starting point for understanding differences between emulsification efficiency between inline and batch modes of operation with relevance for both equipment design and process scale-up.

  • 29.
    Håkansson, Andreas
    et al.
    Lunds universitet.
    Fuchs, Laszlo
    Innings, Fredrik
    Revstedt, Johan
    Bergenståhl, Björn
    Trägårdh, Christian
    Visual observations and acoustic measurements of cavitation in an experimental model of a high-pressure homogenizer2010In: Journal of Food Engineering, ISSN 0260-8774, E-ISSN 1873-5770, Vol. 100, no 3, p. 504-513Article in journal (Refereed)
    Abstract [en]

    Cavitation is common in high-pressure homogenizers, and has severe negative effects such as noise and mechanical wear, but may also have a beneficial effect in promoting fragmentation. Greater knowledge concerning cavitation in the homogenizer valve is thus important in optimizing the design and utilization of emulsification equipment. The aim of this study was to locate the region of cavitation and to study its dependence on operating conditions. The cavitation in a model of a high-pressure homogenizer is examined in detail. A visualization technique, based on the scattering of light from cavitation bubbles in the flow, has been developed, tested and compared to acoustical measurements. Intense light scattering was observed in the gap of the valve, indicating cavitation bubble growth as well as collapse inside the gap. The scattering intensity increased with increasing inlet pressure and decreased with increasing back pressure.

  • 30.
    Håkansson, Andreas
    et al.
    Lundsuniversitet.
    Fuchs, Laszlo
    Innings, Fredrik
    Revstedt, Johan
    Trägårdh, Christian
    Bergenståhl, Björn
    Experimental validation of k–e RANS-CFD on a high-pressure homogenizer valve2012In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 71, p. 264-273Article in journal (Refereed)
    Abstract [en]

    Since the emulsification in the High-Pressure Homogenizer (HPH) is controlled by hydrodynamic forces, the turbulent flow field in the valve region is of significant interest. Computational Fluid Dynamics (CFD) simulations have been used for this in many studies. However, there are reasons to question if the utilized turbulence models, with their inherent assumptions and simplifications, could accurately describe the influential aspects of the flow.

    This study compares CFD simulations using the methods from previous studies with experimental measurements in a model HPH valve. The results show that the region upstream of the gap can be described accurately regardless of turbulence model and that the gap region can be captured by using one of the more refined k−ε models. None of the studied turbulence models were able to describe the details of the highly turbulent region downstream of the gap. The obtained results are also discussed in relation to generalizability and limitations in using CFD simulations for understanding the emulsification in the HPH.

  • 31.
    Håkansson, Andreas
    et al.
    Lund University, Department of Food Technology, Engineering and Nutrition.
    Fuchs, Laszlo
    Lund University, Department of Energy Sciences.
    Innings, Fredrik
    Tetra Pak Processing Systems, Lund.
    Revstedt, Johan
    Lund University, Department of Energy Sciences.
    Trägårdh, Christian
    Lund University, Department of Food Technology, Engineering and Nutrition.
    Bergenståhl, Björn
    Lund University, Department of Food Technology, Engineering and Nutrition.
    High resolution experimental measurement of turbulent flow field in a highpressure homogenizer model and its implications on turbulentdrop fragmentation2011In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 66, no 8, p. 1790-1801Article in journal (Refereed)
    Abstract [en]

    Particle image velocimetry is performed on a model of a high pressure homogenizer, scaled for qualitative similarity of the one phase turbulent flow field in a production scale homogenizer. Flow fields in gap entrance, gap and gap outlet chamber are obtained with high resolution. The measurements show gap flow development and formation of a turbulent wall adherent jet when exiting into the outlet chamber. Turbulent kinetic energy spectra show how the turbulent energy available for fragmentation is transported over distance along the jet centre axis.

    The high resolution images are also used together with a Kolmogorov-Hinze theory framework for discussing drop fragmentation together with a direct evaluation of disruptive stresses from measurements. For the turbulent inertial mechanism large drops experience high fragmenting force close to eight gap heights downstream of the gap exit where as this occurs closer to 20 gap heights for smaller drops. The turbulent viscous mechanism is most efficient at a downstream distance of eight gap heights into the outlet chamber for all drops sizes.

  • 32.
    Håkansson, Andreas
    et al.
    Lund University.
    Fuchs, Laszlo
    Lund University.
    Innings, Fredrik
    Tetra Pak Processing Systems.
    Revstedt, Johan
    Lund University.
    Trägårdh, Christian
    Lund University.
    Bergenståhl, Björn
    Lund University.
    Velocity measurements of turbulent two-phase flow in a high-pressure homogenizer model2013In: Chemical Engineering Communications, ISSN 0098-6445, E-ISSN 1563-5201, Vol. 200, no 1, p. 93-114Article in journal (Refereed)
    Abstract [en]

    The effect of disperse phase volume fraction on the turbulence in a scale model of a high-pressure homogenizer was studied experimentally. Velocity fields of the continuous phase were measured using particle image velocimetry. Refractive index matching combined with digital filtering enabled measurement with disperse phase present. Geometry and physical properties were carefully scaled in order to ensure turbulent flow and disperse phase modulation comparable to that of a technical high-pressure homogenizer. The results show a widening of the jet downstream of the gap and increased Reynolds stresses in the region of high turbulence intensity. This is consistent with previous experiments under similar conditions. Furthermore, the spectra of turbulent kinetic energy were investigated, indicating that the increase in turbulent kinetic energy is mainly due to an increase in energy of eddies of large length scales.

  • 33.
    Håkansson, Andreas
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen.
    Hounslow, Mike
    Simultaneous determination of fragmentation and coalescence rates during pilot-scale high-pressure homogenization2013In: Journal of Food Engineering, ISSN 0260-8774, E-ISSN 1873-5770, Vol. 116, no 1, p. 7-13Article in journal (Refereed)
    Abstract [en]

    The emulsification process is primarily determined by the rate of fragmentation and coalescence of emulsion drops. However, there is presently no fast, reliable method for measuring these rates for pilot and production scale high pressure homogenizers.

    In this paper a method for simultaneous estimating fragmentation and coalescence is developed and tested based on the work of Hounslow and Ni (2004). Kernel type as well as rate extraction is performed based on the development of the total number of drops when recirculation an emulsion through a high-pressure homogenizer. The method has many advantages such as not requiring any specialty chemicals or complex analytical equipment. All measurements are made using laser diffraction equipment that is already standard for analyzing the effect of homogenization.

    Experiments show fragmentation and coalescence rates close to that seen in previous studies and the scaling of coalescence rate and fragmentation with homogenizing pressure is in accordance with theory.

  • 34.
    Håkansson, Andreas
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Innings, Fredrik
    Tetra Pak AB & Lund University.
    The dissipation rate of turbulent kinetic energy and its relation to pumping power in inline rotor-stator mixers2017In: Chemical Engineering and Processing, ISSN 0255-2701, E-ISSN 1873-3204, Vol. 115, p. 46-55Article in journal (Refereed)
    Abstract [en]

    The theoretical understanding of inline rotor-stator mixer (RSM) efficiency, described in terms of the dissipation rate of turbulent kinetic energy as a function of mixer design and operation, is still poor. As opposed to the correlations for shaft power draw, where a substantial amount of experimental support for the suggested correlations exists, the previously suggested correlations for the dissipation rate of turbulent kinetic energy have not been experimentally validated based on primary hydrodynamic measurements. This study uses energy conservation to reformulate the previously suggested dissipation rate correlations in terms of pumping power which allows for empirical testing. The dimensionless pumping power of three investigated geometrically dissimilar inline RSMs were found to be qualitatively similar to that of centrifugal pumps and decrease linearly with the inline RSM flow number. The previously suggested models for turbulent dissipation in inline RSMs are inconsistent with this observation. Using this reformulation approach, the previously suggested correlation for power-draw is extended to a correlation for dissipation. A new model is suggested based on conservation of energy and angular momentum, and the empiric pumping power relationship. The new model compares well to CFD simulations of total dissiaption and show reasonable agreement to emulsification drop size scaling.

  • 35.
    Håkansson, Andreas
    et al.
    Lunds universitet.
    Innings, Fredrik
    Revstedt, Johan
    Trägårdh, Christian
    Bergenståhl, Björn
    Estimation of turbulent fragmenting forces in a high-pressure homogenizer from computational fluid dynamics2012In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 75, p. 309-317Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to find models for turbulent fragmenting forces in the high-pressure homogeniser from data available in Computational Fluid Dynamics (CFD) simulations with Reynolds Averaged Navier Stokes (RANS) turbulence models. In addition to the more common RANS k–ε turbulence models, a Multi-scale k–ε model was tested since experimental investigations of the geometry imply large differences in behaviour between turbulent eddies of different length-scales.

    Empiric models for the driving hydrodynamic factors for turbulent fragmentation using the extra information given by multi-scale simulations were developed. These models are shown to give a more reasonable approximation of local fragmentation than models based on the previously used RANS k–ε models when comparing to hydrodynamic measurements in an experimental model.

  • 36.
    Håkansson, Andreas
    et al.
    Lund University.
    Innings, Fredrik
    Tetra Pak Processing Systems.
    Trägårdh, Christian
    Lund University.
    Bergenståhl, Björn
    Lund University.
    A high-pressure homogenization emulsification model: improved emulsifier transport and hydrodynamic coupling2013In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 91, p. 44-53Article in journal (Refereed)
    Abstract [en]

    The high-pressure homogenizer emulsification modelling framework by Håkansson et al. (2009a, Chemical Engineering Science 64, 2915–2925; 2009b. Food Hydrocolloids 23, 1177–1183), is further developed in this study. The model, including the simultaneous fragmentation of drops, coalescence of drops and kinetic adsorption of macromolecular emulsifiers, is improved with regard to two points. First, the transport of adsorbed emulsifier between drops of different sizes due to the fragmentation and coalescence of drops, is included using bivariate population balances. Second, the coupling of hydrodynamics to the emulsification model is improved using information from recent hydrodynamic investigations. The proposed framework is exemplified using a set of physically reasonable kernels and a production scale high-pressure homogenizer geometry, showing realistic emulsification results.

  • 37.
    Håkansson, Andreas
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen. Lunds universitet.
    Magnusson, Emma
    Bergenståhl, Björn
    Nilsson, Lars
    Hydrodynamic radius determination with asymmetrical flow field-flow fractionation using decaying cross-flows: Part I. A theoretical approach2012In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1253, p. 120-126Article in journal (Refereed)
    Abstract [en]

    Direct determination of hydrodynamic radius from retention time is an advantage of the field-flow fractionation techniques. However, this is not always completely straight forward since non-idealities exist and assumptions have been made in deriving the retention equations. In this study we investigate the effect on accuracy from two factors: (1) level of sophistication of the equations used to determine channel height from a calibration experiment and (2) the influence of secondary relaxation on the accuracy of hydrodynamic radius determination. A new improved technique for estimating the channel height from calibration experiments is suggested. It is concluded that severe systematic error can arise if the most common channel height equations are used and an alternative more rigorous approach is described. For secondary relaxation it is concluded that this effect increases with the cross-flow decay rate. The secondary relaxation effect is quantified for different conditions. This is part one of two. In the second part the determination of hydrodynamic radius are evaluated experimentally under similar conditions.

  • 38.
    Håkansson, Andreas
    et al.
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Mortensen, Hans Henrik
    Tetra Pak.
    Andersson, Ronnie
    Chalmers University.
    Innings, Fredrik
    Tetra Pak & Lund University.
    Experimental investigations of turbulent fragmenting stresses in a rotor stator mixer. Part 1.: estimation of turbulent stresses and comparison to breakup visualizations2017In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 171, p. 625-637Article in journal (Refereed)
    Abstract [en]

    Despite large industrial relevance, the relation between rotor-stator geometry, hydrodynamics and drop breakup is poorly understood, partly since no methods for measuring the fragmenting stresses acting on drops have been established. This study attempts to bridge this gap by developing, applying and evaluating two approaches for estimating local turbulent stresses based on particle image velocimetry data: namely one traditional but indirect approach based on the dissipation rate of turbulent kinetic energy, and another more direct approach based on the spatial turbulent spectrum that has proven useful in other high-intensity emulsification processing. The approaches are evaluated in terms of validity of underlying assumptions, how they compare to breakup visualizations in the same geometry and with regard to the reliability of primary measurables. Results show three consistent regions of high stress in the rotor-stator region: in a plume extending into the stator-hole from the trailing edge, in the shear layers of the jet exiting the hole and in the macroscopic flow structure formed after the rotor blocks a stator hole. Following, a drop travelling along an average velocity flow field, the measurement predict disrupting stresses exceeding the stabilizing stress at the stator hole exit, at approximately the same position where drop breakup is observed in breakup visualizations. Both methods are therefore able to predict the most likely breakup positions. It is also concluded that both methods have limitations, and that average stress alone cannot describe all aspects of the fragmentation process in rotor-stator mixers. (C) 2017 Elsevier Ltd. All rights reserved.

  • 39.
    Håkansson, Andreas
    et al.
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, Faculty of Natural Science, Avdelningen för mat- och måltidsvetenskap.
    Rayner, Marilyn
    Lunds universitet.
    General principles of nanoemulsion formation by high-energy mechanical methods2018In: Nanoemulsions: formulation, applications, and characterization / [ed] Seid Mahdi Jafari and David Julian McClements, Elsevier, 2018, p. 103-139Chapter in book (Other academic)
    Abstract [en]

    Emulsion formation is a challenging task. Breaking a large drop into smaller fragments gives rise to an increase in the total interfacial area and, consequently, in the interfacial energy. External energy must, therefore, be supplied to form an emulsion. Nanoemulsion formation is even more challenging since small drops require even higher interfacial energy.

    The high-energy methods are designed to supply the energy required for emulsification by subjecting it to a disruptive hydrodynamic stress, that is, laminar or turbulent shear or cavitation. This chapter provides an overview of the current understanding of the mechanical principles of the high-energy methods. It discusses how they give rise to emulsification, both in terms of the traditional stress-balance description and of dynamic theories of emulsification. Special emphasis is placed on the difference between forming micrometer range emulsions and nanoemulsions.

  • 40.
    Håkansson, Andreas
    et al.
    Lund University.
    Trägårdh, Christian
    Lund University.
    Bergenståhl, Björn
    Lund University.
    A method for estimating effective coalescence rates during emulsification from oil transfer experiments2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 374, no 1, p. 25-33Article in journal (Refereed)
    Abstract [en]

    The Oil Transfer Technique (OTT) was developed by Taisne et al. [1] to measure coalescence during emulsification and has been applied since in several studies. One of the main drawbacks of this technique is that it only gives a qualitative measure of coalescence. This paper proposes a new evaluation method of OTT experimental results for estimating qualitative coalescence rates, e.g. for investigating the scaling of coalescence with emulsification parameters (such as homogenizing pressure, and emulsifier concentration).

    The method is based on comparison with simulated OTT experiments using bivariate Population Balance Equation models. Simulations have been performed under a wide variety of conditions in order to investigate the influence of assumptions on coalescence and fragmentation kernels. These investigations show that the scaling of coalescence rates could be determined accurately when the scaling of efficient residence time of drops in the active region of homogenization is known. The proposed evaluation method is also exemplified by analyzing OTT data from two previously published studies.

  • 41.
    Håkansson, Andreas
    et al.
    Lunds universitet.
    Trägårdh, Christian
    Bergenståhl, Björn
    Dynamic simulation of emulsion formation in a high pressure homogenizer2009In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 64, no 12, p. 2915-2925Article in journal (Refereed)
    Abstract [en]

    A simulation model for emulsification in high pressure homogenization (HPH), based on a population balance approach, is developed assuming it to be controlled by three simultaneous processes; fragmentation, coalescence and adsorption of a macromolecular emulsifier. The aim is to investigate the implications of adding a set of models together; studying the effects of dynamics, size effects and process interactions.

    For fragmentation, turbulent inertial and turbulent viscous forces are included using a dynamic model based on the Weber and Capillary number. It was extended to include a deformation time scale.

    The rate of adsorption and coalescence is assumed to be controlled by the collision rate of macromolecular stabilizer and bare interface, modeled using convective and diffusive transport in turbulent flow.

    By comparing simulation results to general trends found in the literature, it can be concluded that the models can reproduce the general HPH process well. By dividing the active region of emulsification in the homogenizing valve into discrete steps, the dynamic process could also be examined, indicating the homogenization process being composed of three stages with coalescence predominantly found in the last one.

  • 42.
    Håkansson, Andreas
    et al.
    Lunds universitet.
    Trägårdh, Christian
    Bergenståhl, Björn
    Studying the effects of adsorption, recoalescence and fragmentation in a high pressure homogenizer using a dynamic simulation model2009In: Food Hydrocolloids, ISSN 0268-005X, E-ISSN 1873-7137, Vol. 23, p. 1177-1183Article in journal (Refereed)
    Abstract [en]

    The emulsification in a high pressure homogenizer was studied using a dynamic simulation model based on the population balance equation. The model includes fragmentation, recoalescence and adsorption of macromolecular emulsifier and uses a simple flow model in order to link the hydrodynamics in the homogenizer to the three physical processes mentioned above.

    A computer model offers an interesting opportunity to study the effect of model assumptions on the overall outcome of the process. The computer model is also an interesting complement to experiments in this case since internal measurements in the active region of homogenization are very hard to carry out, due to small scales and high forces, and information on the spatial position of the different processes is of great importance in design.

    Based on a set of assumptions, mainly that the turbulent jet responsible for break-up can be described by a one dimensional model and that the macromolecular emulsifiers hindrance of recoalescence can be described by a wall like repulsion, it is shown that the active region of homogenization can be divided into two zones; a narrow zone with fast fragmentation and nearly no recoalescence in the most intense part of the region followed by a recoalescence zone as drop–drop interactions starts to dominate with decreasing turbulence intensity. The effect of operating parameters is seen to be close to the ones found from experiment.

    The results are discussed in relation to a flow field obtained by a simplistic CFD and assumptions made about hydrodynamics and emulsifier behavior.

  • 43.
    Håkansson, Andreas
    et al.
    Department of Food Technology, Engineering and Nutrition, Faculty of Engineering LTH, Lund University.
    Ulmius, Matilda
    Biomedical Nutrition, Pure and Applied Biochemistry, Faculty of Engineering LTH, Lund University.
    Nilsson, Lars
    Department of Food Technology, Engineering and Nutrition, Faculty of Engineering LTH, Lund University.
    Asymmetrical flow field-flow fractionation enables the characterization of molecular and supramolecular properties of cereal beta-glucan dispersions2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 87, no 1, p. 518-523Article in journal (Refereed)
    Abstract [en]

    In this paper we study the properties of molecular and supra molecular species in cereal beta-glucan solutions/dispersions by the utilization of asymmetrical flow field-flow fractionation coupled to multi-angle light scattering and refractive index (AsFIFFF-MALS-RI) detectors. The samples were purified barley and oat beta-glucans which were dissolved in aqueous solution using either mild conditions or more harsh treatments with alkali. Dissolution in 0.5 M NaOH was not sufficient to eliminate aggregated structures in barley beta-glucan. The results in this paper show how distinction can possibly be made between molecular and supra molecular species using scaling approaches and conformational parameters obtained from AsFIFFF-MALS-RI over the entire size distribution. Small species in the barley beta-glucan samples display properties ranging from elongated conformation to random coil conformation. Aggregates have low apparent densities and a swollen micro gel structure. Oat beta-glucan displays no properties that can be attributed to a molecularly dissolved beta-glucan showing that dissolution was incomplete. The aggregate properties analyzed were similar between oat and barley beta-glucan.

  • 44.
    Håkansson, Andreas
    et al.
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Zishan, Chaudhry
    Tetra Pak Processing Systems AB.
    Fredrik, Innings
    Tetra Pak Processing Systems AB.
    Model emulsions to study the mechanism of industrial mayonnaise emulsification2016In: Food and Bioproducts Processing, ISSN 0960-3085, E-ISSN 1744-3571, Vol. 98, p. 189-195Article in journal (Refereed)
    Abstract [en]

    Mechanistic understanding of industrial food-emulsification is necessary for optimal operation and design. Industrial mayonnaise production is yet poorly understood, partly due to a lack of experimental data and partly due to the complexity of the product.

    This study suggests a systematic method for building mechanistic insight, by investigating successively more complex model emulsions in industrial rotor–stator mixers, comparing to idealized theories identifying points of departure. As a first step, a high volume fraction (>50%) and high viscosity (>100 mPa s) model emulsion with a non-ionic surfactant acting as emulsifier is investigated in two industrial-scale mixers (one batch and one continuous inline mixer) at varying rotor tip-speeds.

    The resulting drop diameter to rotor tip-speed scaling suggest turbulent viscous fragmentation of the model emulsion in both mixers despite the high volume fraction of disperse phase which could be expected to lead to significant non-idealities such as extensive coalescence and concentration effect-dominated fragmentation. If the other non-idealities (e.g. egg yolk emulsifying system and non-Newtonian rheology) would not influence the emulsification, this suggests the same mechanism for mayonnaise emulsification. An outline for continued work on successively more complex model-emulsions is discussed in order to further enhance understanding.

  • 45. Magnusson, Emma
    et al.
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Praktisk-estetiska ämnen.
    Janiak, John
    Bergenståhl, Björn
    Nilsson, Lars
    Hydrodynamic radius determination with asymmetrical flow field-flow fractionation using decaying cross-flows: Part II. Experimental evaluation2012In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1253, p. 127-133Article in journal (Refereed)
    Abstract [en]

    In this study we investigate the effect of programmed cross-flows on the error in the hydrodynamic radii (rh) determination with asymmetrical flow field-flow fractionation (AsFlFFF). Three different standard polystyrene particles (nominal radii of 30 and 40 and 50 nm) are fractionated with exponentially and linearly decaying cross-flows with different decay rates. Hydrodynamic radii are calculated according to retention theory including steric effects. Rapid decay is expected to give rise to systematic deviations in rh determination. The error in rh was found to be small when decay rates with half-lives longer than 6 min were used, whereas steeper decays could give rise to errors as high as 16% of the particle size. The error is often explained in terms of secondary relaxation. However, comparisons show that experimental errors are significantly larger than what would be expected due to secondary relaxation, suggesting that other factors also have to be considered in order to fully understand deviations for rapidly decaying cross-flow.

  • 46.
    Mortensen, Hans Henrik
    et al.
    Tetra Pak Processing Systems.
    Arlöv, Dragana
    Tetra Pak Processing Systems.
    Innings, Fredrik
    Tetra Pak Processing Systems & Lund University.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    A validation of commonly used CFD methods applied to rotor stator mixers using PIV measurements of fluid velocity and turbulence2018In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 177, p. 340-353Article in journal (Refereed)
    Abstract [sv]

    Computational fluid dynamics (CFD) has been applied extensively for studying rotor-stator mixers (RSM) in the past, both as a design-tool and in modelling mixing and emulsification. Modelling is always a balance between accuracy and computational cost. The theoretically soundest methods (i.e. fully resolved transient simulations) have often been deemed unfeasible, and the majority of previously published studies use severe simplifications (i.e. k-ε models for turbulence and multiple reference frame for rotation). High quality experimental validation is in great need, but are rare, due to the lack of local fluid velocity measurement.

    Experimental validations of CFD on RSMs have previously been provided using laser Doppler aneometry. This study provides the first validation using particle image velocimetry, allowing for substantially higher spatial resolution than with the previously used techniques. The objective of this study is to map the possibilities and limitations of these commonly used CFD modelling approaches for RSMs. Special emphasis is put on validating the dissiaption rate of turbulent kinetic energy (TKE). Despite being the parameter used for linking CFD to mixing or dispersion models, this has not been the subject of experimental validation in previous studies.

    Based on the validations, a list of best practice recommendations are given (in terms of turbulence model, mesh resolution and rotation formulation). When adhering to these, the CFD model accurately captures power draw, flow number, and the detailed velocity field inside the region where mixing and dispersion takes place. The dissipation rate of TKE is captured qualitatively but underestimate experimental values. Implications in terms of limitations are discussed in detail, including estimations of accuracy implications for emulsification and mixing modelling.

  • 47.
    Mortensen, Hans Henrik
    et al.
    Tetra Pak Processing Systems.
    Innings, Fredrik
    Tetra Pak Processing Systems & Lund University.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Local levels of dissipation rate of turbulent kinetic energy in a rotor-stator mixer with different stator slot widths: an experimental investigation2018In: Chemical Engineering Research and Design, ISSN 0263-8762, Vol. 130, p. 52-62Article in journal (Refereed)
    Abstract [en]

    Rotor-stator mixers (RSMs) are widely used for emulsification and mixing. However, relatively little is known about the relationship between RSM design, hydrodynamics and performance. Previous studies have investigated shaft power draw as a function of design. However, power draw alone is not sufficient to predict efficiency. In order to understand the effect on performance it is important to investigate how the local turbulent stress is influenced by design parameters.

    This study investigates the effect of stator slot width on the local dissipation rate of turbulent kinetic energy using particle image velocimetry coupled with a sub-resolution modeling approach suggested in previous studies. Results are compared to traditional shaft power draw measurements and a set of emulsification experiments.

    It is concluded that wider slots, although requiring less total shaft power, provide a higher maximal (time-averaged) dissipation rate of TKE, which explains why they give rise to more efficient drop breakup. Apparently, more of the power input is transformed into pumping for the narrower slots which leaves less energy for turbulent dissipation.

    The study illustrates the need for supplementing traditional power draw measurements with local flow characterization in order to better understand the relationship between RSM hydrodynamics and dispersion performance.

  • 48.
    Mortensen, Hans Henrik
    et al.
    Tetra Pak Processing Systems AB.
    Innings, Fredrik
    Tetra Pak Processing Systems AB & Lund University.
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    The effect of stator design on flowrate and velocity fields in a rotor-stator mixer: an experimental investigation2017In: Chemical engineering research & design, ISSN 0263-8762, E-ISSN 1744-3563, Vol. 121, p. 245-254Article in journal (Refereed)
    Abstract [en]

    Rotor-stator mixers (RSMs) are available in different designs, e.g. with different number of stator slots and slot dimensions. However, the relationship between stator design and the RSM hydrodynamics is not well understood. Consequently, manufacturers still base design and stator screen recommendations on trial-and-error.

    This study reports experimental measurements of how the flowrate through the stator slots, and velocity profiles in the region of relevance for mixing and breakup, is influenced by the stator slot width, using particle image velocimetry. It is concluded that the flowrate can be described by a design dependent flow number for all investigated geometries and that the flow number decreases with increasing slot width. Moreover, by studying the velocity profiles at different rotor speeds and designs, it is concluded that the velocity profile, its skewness and the proportion of back-flow (fluid re-entering the slot) scales with the flow number of the design. This suggests that the flow number, in addition to rotor speed, is a highly relevant parameter for describing the effect of design on batch RSM hydrodynamics.

  • 49. Muharemovic, Kanita
    et al.
    Taboul, Nicole
    Håkansson, Andreas
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Humanvetenskap.
    Home cooking trends and dietary illness: nutritional compliance ofrecipes in a Swedish food magazine 1970–20102016In: Scandinavian Journal of Public Health, ISSN 1403-4948, E-ISSN 1651-1905, Vol. 44, no 2, p. 195-201Article in journal (Refereed)
    Abstract [en]

    Aims: To investigate the trends in nutritional compliance of recipes from a Swedish food magazine to offer a perspective on the effects of home cooking on public health. Methods: The nutritional content of 654 recipes from magazine issues published in 1970, 1980, 2000, and 2010 were collected. The recipes were analyzed for macronutrient energy contribution, sodium content, and composition. Results: The recipes were in poor agreement with nutritional recommendations (excessive fat, protein, and sodium and insufficient carbohydrate and fiber content). Significant changes between 1970 and 2010 were the increased calorific contribution of fat (from 38 to 46%) and the reduced contribution of proteins (from 27 to 21%). The calorific contribution from spreads, cheese, bread, and fruit and vegetables have increased significantly, whereas the contribution from meat has decreased significantly. Conclusions: The poor nutritional compliance identified in this work indicates that consumers using the recipes as norms for home cooking risk following an unhealthy diet. This might have adverse effects on public health. However, the recipes have not become less compliant over time and therefore the data do not show an adverse trend in these norms.

  • 50.
    Nyberg, Maria
    et al.
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Bryntorp, Anna
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Håkansson, Andreas
    Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap. Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL).
    Höijer, Karin
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Olsson, Viktoria
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Rothenberg, Elisabet
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Sepp, Hanna
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Wendin, Karin
    Kristianstad University, Research Environment Food and Meals in Everyday Life (MEAL). Kristianstad University, School of Education and Environment, Avdelningen för Mat- och måltidsvetenskap.
    Exploring the meal concept: an interdisciplinary literature overview2015Conference paper (Refereed)
    Abstract [en]

    The meal concept is used in varying contexts, and within several scientific fields, however often without a clear definition of what it includes. The meal has been identified as a subject in multiple research areas such as nutrition, medicine, sensory science, history, design product development, food service, biology, physiology, anthropology, sociology, psychology, marketing and so forth 1. A meal may be defined and identified by the time of the day, by its energy content and how the food is combined as well as by its social interactions, implying that it may be understood in relation to the food itself as well as to the social and cultural context 2. The meal has also been discussed in relation to the concept of “snacks”, where a meal has been defined as a “structured food event”, while “snacks” represent “unstructured food events”3 . Some attempts have been made in order to define the meal and also to present a more holistic model of what it includes. One way of defining the meal is by using certain cues related to food as well as the environment 4. Another example is the Five Aspects Meal Model (FAMM) which was developed as a model in the early 2000s 5, with the ambition to capture an entirety of the meal by including the room, the meeting, the product, the logistics and the atmosphere in defining and understanding a meal. Although there have been many attempts trying to find a general and precise definition, the complexity makes it difficult, and maybe impossible, to capture the meal concept in a single definition 6. Different disciplines focus on various aspects, which may complicate a common understanding 7,8,9.

    It has been stated that meals are only one form of eating 10, and that the meal alone does not capture the diversity of todays’ eating. Still, it is recurrently used as a point of reference and as a norm for discussions concerning food and eating. The meal concept is however in constant change and must be understood in relation to societal patterns and norms, how we organize our eating and what role food plays as a social and cultural glue 2, but also in relation to our perception of health, sustainability, convenience and so forth. Other concepts, such as “eating episodes” 11,12, “eating occasions” see f ex. 13 and “eating events” 14 have also been used as attempts to illuminate the complexity of food habits. Nonetheless, the meal is still universally used and recurrent in various research works, and therefore it is of importance to investigate how the concept is actually used and understood in the different areas related to food- and meal science, an interdisciplinary field studying food and meals within Food scienceNutrition and health, and Food culture and communication.

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