Starch in Processed Potatoes -Influence of Tuber Structure, Thermal Treatments and Amylose/Amylopectin Ratio

The potato is one of our most important food crops, being sold in its natural state or processed into a wide range of products. Starch, by far the most abundant component in the tuber, is greatly affected by heat processing. Therefore it is logical to study starch thermal properties within the tuber tissue, although most previous studies have focused on starch-water model systems. One of the main purposes of this work was to analyse thermal events such as gelatinisation, retrogradation and annealing in both tissue samples and starch-water systems, and to relate starch thermal effects to the characteristics of potato tubers and processing conditions. The main methods used were differential scanning calorimetry (DSC) and microscopy. The DSC method has been widely used to study starch and is also applicable to the analysis of potato tissue samples. Several microscopic techniques were used to study the potato microstructure at different levels of magnification. Information obtained from micrographs was further used to interpret results from DSC analyses. Several characteristics of the raw material were shown to influence the thermal properties of starch. Potato variety and cultivation year, as well as properties related to dry matter components and their distribution within the tuber, were very important, whereas the tuber size was insignificant. The gelatinisation of starch within tissue is shifted to higher temperatures as compared with starch-water systems, a fact that also influences the effects of annealing. Furthermore, starch from the central parts of the tuber had categorically higher gelatinisation temperatures than starch from other tuber tissue zones. Retrogradation rate, in terms of increased enthalpy of melting recrystallised amylopectin with time, was affected by variety whereas melting temperatures were not. However, the differences in gelatinisation and retrogradation between varieties could not be related to cooking type, i.e. mealiness. To understand more about the influence of amylose and amylopectin respectively on different starch characteristics, potatoes with large variations in amylose content were analysed. Amylose content roughly ranged from 1 to 78 %. In high-amylose starch, properties such as granule morphology, gelatinisation, and retrogradation were severely altered compared with normal starch. In starch with 99 % amylopectin differences were less extensive. When subjecting some of these starches to different temperature treatments, it was shown that important nutritional features such as resistant starch content and starch hydrolysis rate are mainly affected by amylose content. A synergistic effect between retrograded amylopectin and amylose may have an additional effect on these properties

Is a literary canon necessary? : A comparative study based on seven senior high school teachers´ different approaches towards the place of canon in the education of Swedish

English title: Is a literary canon necessary? A comparative study based on seven senior high school teachers´ different approaches towards the place of canon in the education of Swedish.   The purpose of this study is to describe and analyze how seven senior high school teachers relate to a literary canon in Swedish while teaching literature in senior high school, identifying similarities and differences among the teachers’ view and opinions about an outspoken formal literary canon and a silent, informal canon. The earlier research opens the door slightly to the American debate and gives insight about the complexity of the concept of canon. The study continues with exploring possible relations to postcolonial theory and didactics.     The study reveals that the majority of the concerns against canon are that too much centrally governed education may decrease the motivation and commitment of the teacher. In addition, the dominant canon passivizes a certain variety of literature, thus various points of views. On the other hand, views on the equalizing effect of canon on the level of education and its benefits in increased knowledge of the history of the literature are salient.

Occupational therapists´ experiences of using outdoor activities as intervention

Syfte: Syftet med studien var att undersöka vilka erfarenheter arbetsterapeuter har gällande friluftsaktivitet som intervention för vuxna med psykisk ohälsa samt att identifiera möjligheter och hinder att använda friluftsaktivitet som intervention.Metod: Författarna valde en kvalitativ ansats och utförde studien med semistrukturerade intervjuer och analyserade dessa med kvalitativ innehållsanalys.Resultat: Resultatet visar att arbetsterapeuter anser att naturen främjar välmående och att friluftsaktiviteter skapar möjligheter för gemenskap, delaktighet och social interaktion. Möjligheter eller hinder för arbetsterapeuter att använda friluftsaktiviteter som intervention var beroende av ett flertal faktorer varav några var uppdragets omfattning, resurser, samarbeten samt närhet till naturen och tillgång till material. Slutsats: Det framkommer att naturen ökar välmående och att många arbetsterapeuter är positiva till att använda friluftsaktiviteter som intervention. Arbetsterapeuterna ser hinder men också lösningar, dock är det ofta helt beroende på arbetsterapeuten själv att starta ett projekt. En nationell handlingsplan behövs, men även fler studier. Författarna föreslår en studie där klienters välmående mäts före och efter en intervention kopplad till friluftsaktivitet. Studien genomfördes under pandemin covid-19 (2021) och författarna ser en möjlighet att friluftsaktiviteter som intervention skulle underlätta fysisk distansering men ändå uppfylla behoven hos klienter med psykisk ohälsa. Aim: The purpose of this study was to examine the experience of occupational therapists in using outdoor activity as an intervention in adults with mental illness and identify possibilities for and obstacles against using outdoor activity as an intervention. Method: the authors chose a qualitative approach using semi-structured interviews and analyzed the data using qualitative content analysis.Result: The results show that occupational therapists deem nature as beneficial for wellbeing and that outdoor activity creates opportunities for connection, participation and social interaction. Possibilities and obstacles for the occupational therapist to use outdoor activities as an intervention were dependent on many different factors including the scope of assignment, resources, closeness to nature and access to equipment and materials.Conclusion: It emerges as fact that nature increases wellbeing and that many occupational therapists are positive to try outdoor activity as an intervention. The occupational therapists see both opportunities and obstacles, though it is often dependent on the individual therapist to kickstart a new project. A national action plan is needed, as well as further studies. The authors suggest a study where wellbeing in clients is measured before and after an intervention connected to outdoor activity. This study was conducted during the COVID-19 pandemic (2021) and the authors see an opportunity for outdoor activities to make physical distancing easier and still meet the needs of clients with mental illness.

Effects of time/temperature treatments on potato (Solanum tuberosum) starch: a comparison of isolated starch and starch in situ.

Previously, time/temperature treatments of starch have been performed mainly on starch/water systems. In this study the same time/temperature treatments were applied to starch/water systems and to potato starch in situ. Two potato varieties (Solanum tuberosum cultivars Asterix and Bintje) were used. The effect of time/temperature treatments on gelatinisation behaviour was evaluated using differential scanning calorimetry (DSC). A blanching process was simulated by heating samples to 74 °C and then cooling them to 6 °C. A DSC scan showed that starch was completely gelatinised after this treatment. Retrogradation of amylopectin increased during storage at 6 °C from 0 to 24 h after blanching. Annealing of starch, with the aim of altering cooking properties, was performed by heating samples to temperatures below the gelatinisation onset temperature. Treating samples at 50 °C for 24 h caused a shift in gelatinisation onset temperature of 11-12 °C for isolated starch and 7-11 °C for in situ samples. The extent of the annealing effect depended on the difference between onset and annealing temperatures, and prolonged treatment time increased the effect. Starch/water systems and tissue samples behaved similarly when exposed to time/temperature treatments. The most apparent difference was the shift of gelatinisation to higher temperatures in tissue samples

Occupational therapists´ experiences of using outdoor activities as intervention

Syfte: Syftet med studien var att undersöka vilka erfarenheter arbetsterapeuter har gällande friluftsaktivitet som intervention för vuxna med psykisk ohälsa samt att identifiera möjligheter och hinder att använda friluftsaktivitet som intervention.Metod: Författarna valde en kvalitativ ansats och utförde studien med semistrukturerade intervjuer och analyserade dessa med kvalitativ innehållsanalys.Resultat: Resultatet visar att arbetsterapeuter anser att naturen främjar välmående och att friluftsaktiviteter skapar möjligheter för gemenskap, delaktighet och social interaktion. Möjligheter eller hinder för arbetsterapeuter att använda friluftsaktiviteter som intervention var beroende av ett flertal faktorer varav några var uppdragets omfattning, resurser, samarbeten samt närhet till naturen och tillgång till material. Slutsats: Det framkommer att naturen ökar välmående och att många arbetsterapeuter är positiva till att använda friluftsaktiviteter som intervention. Arbetsterapeuterna ser hinder men också lösningar, dock är det ofta helt beroende på arbetsterapeuten själv att starta ett projekt. En nationell handlingsplan behövs, men även fler studier. Författarna föreslår en studie där klienters välmående mäts före och efter en intervention kopplad till friluftsaktivitet. Studien genomfördes under pandemin covid-19 (2021) och författarna ser en möjlighet att friluftsaktiviteter som intervention skulle underlätta fysisk distansering men ändå uppfylla behoven hos klienter med psykisk ohälsa. Aim: The purpose of this study was to examine the experience of occupational therapists in using outdoor activity as an intervention in adults with mental illness and identify possibilities for and obstacles against using outdoor activity as an intervention. Method: the authors chose a qualitative approach using semi-structured interviews and analyzed the data using qualitative content analysis.Result: The results show that occupational therapists deem nature as beneficial for wellbeing and that outdoor activity creates opportunities for connection, participation and social interaction. Possibilities and obstacles for the occupational therapist to use outdoor activities as an intervention were dependent on many different factors including the scope of assignment, resources, closeness to nature and access to equipment and materials.Conclusion: It emerges as fact that nature increases wellbeing and that many occupational therapists are positive to try outdoor activity as an intervention. The occupational therapists see both opportunities and obstacles, though it is often dependent on the individual therapist to kickstart a new project. A national action plan is needed, as well as further studies. The authors suggest a study where wellbeing in clients is measured before and after an intervention connected to outdoor activity. This study was conducted during the COVID-19 pandemic (2021) and the authors see an opportunity for outdoor activities to make physical distancing easier and still meet the needs of clients with mental illness.

Gelatinization and retrogradation of potato (Solanum tuberosum) starch in situ as assessed by differential scanning calorimetry (DSC).

The thermal behavior of potato starch in situ has been studied and compared to properties of isolated starch. Gelatinization and retrogradation properties were studied by differential scanning calorimetry. One early and three late varieties with different degree of mealiness were examined. The early variety (Solanum tuberosum var. Rocket) had lower dry matter content and lower starch gelatinization temperature than the later varieties (var. Asterix, Bintje and King Edward). Samples from distinct parts of the potato tuber were analysed to compare the tissue zones. The starch in the water-rich pith appeared to gelatinize at a higher temperature than in samples from the outer parts of the tuber. This was seen for isolated starch as well as for starch in situ; however, the differences were more pronounced in situ. To investigate the influence of tuber size, samples were taken from stem end storage parenchyma. No influence of tuber size on the starch gelatinization properties was detected by the method used. Retrogradation properties were also studied for stem end storage parenchyma. Melting temperatures of recrystallized amylopectin did not differ between varieties, though there were small differences in rate of recrystallization as measured by changes in melting transition enthalpy with time

Particle-stabilized emulsions

This chapter describes particle-stabilized emulsions, the so-called Pickering emulsions. The principles behind particle stabilization of emulsions are described. The key properties of particle-stabilized emulsions such as stability, rheology, and the influences of other ingredients on the system, as well as some additional functional properties imparted by the stabilized particles in food emulsion formulations, are highlighted

Starch affecting anti-staling agents and their function in freestanding and pan-baked bread

Anti-staling agents with different mechanisms were added to a normal white wheat bread to investigate the relation between bread staling, amylopectin retrogradation and water-related properties (i.e. water content and distribution between crumb and crust). Bread was baked both as pan-baked and freestanding loaves. The anti-staling agents maltogenic alpha-amylase, distilled monoglyceride and lipase had a direct influence on starch retrogradation, whereas gluten and waxy wheat flour diluted the amylopectin content or changed the ratio between amylose and amylopectin. The degree of staling was measured as the firmness and springiness, together with two new methods, crumbliness and cutability. In addition, the degrees of amylopectin retrogradation and amylose-lipid complex formation were analyzed by differential scanning calorimetry, and the water content, water loss and water migration were measured. The addition of alpha-amylase improved most staling parameters, although the changes were not as large as expected. Furthermore, monoglyceride and lipase increased the formation of amylose-lipid complexes, but only lipase gave better results regarding the specific volume and firmness. Increased amylose-lipid complex formation was seen to increase water migration from crumb to crust. Adding 10% waxy wheat flour appeared to lead to a slight overall improvement i.e. lower water migration and better cutability. Adding gluten or 3% waxy wheat flour only improved the specific volume. The method of baking the loaves, i.e. freestanding or pan-baked, had a greater influence than the anti-staling agents, which shows that bread quality is not always improved by starch affecting anti-staling agents without process changes. (C) 2011 Elsevier Ltd. All rights reserved

Staling Effects When Adding Low Amounts of Normal and Heat-Treated Barley Flour to a Wheat Bread

The properties of a white wheat bread could be changed by adding normal or heat-treated barley flour in small amounts (2 and 4%) to a white wheat bread recipe. Differences regarding gelatinisation as well as retrogradation properties were found when analysing the two flours in model systems. The heat-treated flour was fully gelatinised due to a prior time-, temperature- and pressure-treatment and could therefore absorb larger amounts of water than the other flours. In gelatinised model systems with 40% flour (dry weight basis), the heat-treated barley flour was found to contain less retrograded amylopectin as compared to normal barley flour after storage for up to 14 days, whereas no differences were found at 20%. However, stored breads showed an increased retrogradation of amylopectin (as measured by differential scanning calorimetry, DSC) when 2% pre-treated barley flour was added as compared to an addition of 2% normal barley flour. On the other hand, there were no significant differences at the 4% level. Addition of either of the barley flours resulted in less firm breads during storage as compared to the control breads. An increased water absorption in barley flour and thereby an increased water content in the breads and/or different water binding capacities of the flour blends could explain these results. The present study indicated that water had a stronger influence on the bread firmness than the retrogradation of amylopectin. This conclusion was based on breads with pre-treated barley flour being less firm than breads with normal barley flour, although the retrogradation, as determined by DSC, was higher