| 1. |
- Ahrné, Lilia, et al.
(författare)
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Improvement of texture by modifying processing conditions
- 2003
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Ingår i: Acta Hortic.. - : International Society for Horticultural Science. - 9789066059764 ; 604, s. 277-277
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Konferensbidrag (refereegranskat)abstract
- Fruit and vegetable processors, faced with the challenge of gaining and maintaining a healthy position in the competitive fruit and vegetable sector, are optimising traditional processes towards product quality. Using frozen potatoes as a case study, the aim of this study was to evaluate the potential of improving the texture of potatoes by modifying the processing conditions. The texture of processed frozen potatoes is the result of the integral effect of the unit operations applied through the production chain. Production of frozen potatoes includes a blanching, a freezing, thawing/cooking step before being served. In this study, blanching temperatures from 70 to 97 °C up to 10 minutes were tested and combined with freezing by two freezing methods, impingement and air-blast freezing. The texture was measured after cooking of frozen potatoes in boiling water. Besides texture, water holding capacity, microstructural evaluation and pectinmethylesterase (PME) activity were determined. Blanching of potatoes prior to freezing can both improve water holding capacity and texture of potatoes, but this effect depends on the freezing rate and blanching temperature. Potatoes frozen with fastest freezing method are firmer and hold more water than the ones frozen by air-blast freezing. Blanching at 70 °C can lead to potatoes that after cooking retain a firmer texture, compared with blanching at 90 °C. The duration of the blanching treatment has also an important effect on texture changes. The studies of PME activity showed a good correlation between texture and PME for blanching at 90 °C, but for blanching at 70°C and longer times, the development of texture does not seem to be solely related to PME activity. Microstructural studies showed that the differences in texture are due to differences in the degree of starch gelatinisation and integrity of the cellular structure.
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| 2. |
- Lopez-Sanchez, Patricia, et al.
(författare)
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Nanostructure and poroviscoelasticity in cell wall materials from onion, carrot and apple : Roles of pectin
- 2020
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Ingår i: Food Hydrocolloids. - : Elsevier B.V.. - 0268-005X .- 1873-7137. ; 98
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Tidskriftsartikel (refereegranskat)abstract
- The hierarchical organisation of polysaccharides in primary plant cell walls is responsible for their unique mechanical properties, and in turn for the textural and rheological properties of plant-based foods and ingredients. It is expected that at the nano scale, the mechanical properties of cell wall materials arise from a combination of structural deformation of the polysaccharide networks and hydraulic properties of the continuous water phase, as has been shown for other cellulose-based composites. Pectin plays a key role in the load bearing properties of (bacterial) cellulose-pectin composites due to its contribution to both hydration structure and the dynamics of water movement. To investigate whether these features are also important in plant cell wall materials we have used a set of advanced characterisation techniques to elucidate cell wall structural features at different length scales (X-ray diffraction and small angle X-ray and neutron scattering) in cell walls from two dicotyledons (apple and carrot) and a non-commelinid monocotyledon (onion). The strength of isolated cell walls was measured under compression and fitted to a poroviscoelastic mechanical model, demonstrating that the mechanical properties of the isolated cell wall materials are directly linked to both polysaccharide networks and fluid flow through the networks. Our results show how pectin polysaccharides influence the viscoelastic behaviour of these materials and contribute to the texture of plant-derived food systems.
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| 3. |
- Van Den Berg, F. D., et al.
(författare)
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Product uniformity control - A research collaboration of european steel industries to non-destructive evaluation of microstructure and mechanical properties
- 2018
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Ingår i: Stud. Appl. Electromagn. Mech.. - : IOS Press. - 9781614998358 ; 43, s. 120-129
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Konferensbidrag (refereegranskat)abstract
- In steel manufacturing, the conventional method to determine the mechanical properties and microstructure is by offline, destructive (lab-)characterisation of sample material that is typically taken from the head or the tail of the coil. Since coils can be up to 7 km long, the samples are not always representative for the main coil body. Also, the time delay (typically a few days) between the actual production and the availability of the characterisation results implies that these results cannot be exploited for real-time adaptation of the process settings. Information about the microstructure and material properties can also be obtained from electromagnetic (EM) and ultrasonic (US) parameters, which can be measured in real-time, non-destructively, and over the full length of the steel strip product. With the aim to improve the consistency in product quality by use of inline EM and US measurements, a European project called "Product Uniformity Control" (PUC) has been set up as a broad collaboration between 4 major European Steel Manufacturers and 10 Universities / Research institutes. Using both numerical simulations and experimental characterisations, we study the inline measured EM and US parameters in regard of the microstructural and mechanical properties. In this way, we aim to establish an improved understanding of their mutual relationships, and to apply this knowledge in existing and new nondestructive evaluation techniques. In this paper, the concerted approach of modelling and experimental validation will be addressed, and results of this work will be shown in combination with inline measured data.
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| 4. |
- Brooke, Robert, 1989-, et al.
(författare)
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Nanocellulose based carbon ink and its application in electrochromic displays and supercapacitors
- 2021
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Ingår i: Flexible and Printed Electronics. - : IOP Publishing Ltd. - 2058-8585. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Conventional electronics have been highlighted as a very unsustainable technology; hazardous wastes are produced both during their manufacturing but also, due to their limited recyclability, during their end of life cycle (e.g. disposal in landfill). In recent years additive manufacturing processes (i.e. screen printing) have attracted significant interest as a more sustainable approach to electronic manufacturing (printed electronics). Despite the field of printed electronics addressing some of the issues related to the manufacturing of electronics, many components and inks are still considered hazardous to the environment and are difficult to recycle. Here we present the development of a low environmental impact carbon ink based on a non-hazardous solvent and a cellulosic matrix (nanocellulose) and its implementation in electrochromic displays (ECDs) and supercapacitors. As part of the reported work, a different protocol for mixing carbon and cellulose nanofibrils (rotation mixing and high shear force mixing), nanocellulose of different grades and different carbon: nanocellulose ratios were investigated and optimized. The rheology profiles of the different inks showed good shear thinning properties, demonstrating their suitability for screen-printing technology. The printability of the developed inks was excellent and in line with those of reference commercial carbon inks. Despite the lower electrical conductivity (400 S m-1 for the developed carbon ink compared to 1000 S m-1 for the commercial inks), which may be explained by their difference in composition (carbon content, density and carbon derived nature) compared to the commercial carbon, the developed ink functioned adequately as the counter electrode in all screen-printed ECDs and even allowed for improved supercapacitors compared to those utilizing commercial carbon inks. In this sense, the supercapacitors incorporating the developed carbon ink in the current collector layer had an average capacitance = 97.4 mF cm-2 compared to the commercial carbon ink average capacitance = 61.6 mF cm-2. The ink development reported herein provides a step towards more sustainable printed green electronics. © 2021 The Author(s).
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| 5. |
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| 6. |
- Fernandez-Anez, Nieves, et al.
(författare)
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Current Wildland Fire Patterns and Challenges in Europe : A Synthesis of National Perspectives
- 2021
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Ingår i: Air, Soil and Water Research. - : SAGE Publications. - 1178-6221. ; 14, s. 1-19
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Forskningsöversikt (refereegranskat)abstract
- Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence.
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| 7. |
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| 8. |
- Heredia-Martinez, A., et al.
(författare)
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Plasma Nitrate and Nitrite Kinetics after Single Intake of Beetroot Juice in Adult Patients on Chronic Hemodialysis and in Healthy Volunteers : A Randomized, Single-Blind, Placebo-Controlled, Crossover Study
- 2022
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Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 14:12
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Tidskriftsartikel (refereegranskat)abstract
- Nitric oxide (NO) contributes to maintaining normal cardiovascular and renal function. NO is generally formed enzymatically by NO synthase in the vascular endothelium. NO bioactivity can also be attributed to dietary intake of inorganic nitrate, which is abundant in our diet, especially in green leafy vegetables and beets. Ingested nitrate is reduced to nitrite by oral commensal bacteria and further to NO systemically. Previous studies have shown that dialysis, by means of removing nitrate and nitrite from the body, can reduce NO bioactivity. Hence, dietary intervention approaches aimed to boost the nitrate–nitrite–NO pathway may be of benefit in dialysis patients. The purpose of this study was to examine the kinetics of plasma nitrate and nitrite after a single intake of nitrate-rich concentrated beetroot juice (BJ) in adult hemodialysis (HD) patients and in healthy volunteers (HV). Eight HD patients and seven HV participated in this single center, randomized, single-blind, placebo-controlled, crossover study. Each participant received a sequential single administration of active BJ (70 mL 400 mg nitrate) and placebo BJ (70 mL 0 mg nitrate) in a random order separated by a washout period of seven days. For the kinetic analysis, blood samples were collected at different time-points before and up to 44 h after BJ intake. Compared with placebo, active BJ significantly increased plasma nitrate and nitrite levels both in HD patients and HV. The area under the curve and the maximal concentration of plasma nitrate, but not of nitrite, were significantly higher in HD patients as compared with HV. In both groups, active BJ ingestion did not affect blood pressure or plasma potassium levels. Both BJs were well tolerated in all participants with no adverse events reported. Our data provide useful information in planning dietary nitrate supplementation efficacy studies in patients with reduced NO bioactivity. © 2022 by the authors.
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| 9. |
- Lucisano, Marco F. C., et al.
(författare)
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On the characterization of the delamination process during impulse pressing
- 2001
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 16:4, s. 362-368
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Tidskriftsartikel (refereegranskat)abstract
- This investigation evaluates the changes in web structure of impulse pressed paper webs. 60 g/m2 wet paper webs made from two stock types (SBK and a 60:40 mixture of SBK with HT-CTMP) were pressed either on laboratory scale or on a research paper machine. The pressing temperature was increased stepwise from 40°C to 290°C. The sampled wet paper webs were either dried in restraint in an oven, freeze-dried, or stored in sealed plastic bags at 4°C. Paper samples were obtained both before and after the pressing event, and the evolution of the cross-sectional solidity profile and transverse permeability was measured as a function of pressing temperature. Delamination was first observed at a pressing temperature of approximately 230°C. For non-delaminated paper webs, the cross-sectional solidity profiles translated uniformly towards higher solidities with increasing pressing temperature. We found no evidence of stratification. For delaminated sheets, however, large fractures were evident, with the damage plane located approximately 1/3 of the way in the total basis weight of the sheet, measured away from the hot surface. The permeability of unloaded samples decreased monotonically with increasing pressing temperature reflecting the fact that the paper samples densified by reduction of the external pore size. The permeability of mechanically compressed, never-dried samples was found to be essentially constant for non-delaminated sheets and to increase significantly for samples which were delaminated. We propose that this phenomenon could be a result of cell wall damage incurred during the delamination process.
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| 10. |
- Lucisano, Marco F. C., et al.
(författare)
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On the mechanism of steam forming during impulse pressing of wet paper webs
- 2001
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 16:4, s. 355-361
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Tidskriftsartikel (refereegranskat)abstract
- Steam forming processes in wet paper webs under-going impulse pressing are characterized here in two different, yet complementary studies. In the first study, we measured the transient temperature profiles of wet paper webs undergoing compression at a constant rate in a heated platen press. Eight micro-thermocouples were embedded into 500 g/m2 SBK wet paper webs at different elevations. The experimental conditions were such that the length of the pressure pulse was varied from 100 ms to 15 s, the initial temperature of the platen press was set from 150°C to 300°C, and the initial dryness of the paper webs were held constant at approximately 30%; approximately 600 experiments were conducted. In the second study, we visualized the flashing event using a novel experimental device. In this part of the work, a 10 cm bed of SBK fibres, with an initial dryness of 40%, was pressurized to approximately 5 bar and heated to 170°C. The hydraulic pressure was then released rapidly causing the water to flash inside the fibre network. The flashing event was recorded by high-speed video and the temperature profile was measured dynamically using fast response thermocouples. The results indicate that steam was formed during the compression phase of the pressure pulse only with long compression times, i.e. t>1 s. In this regime, we found evidence of a heat pipe. Indeed, we found no evidence of a heat pipe with shorter compression times, i.e. t<500 ms. We also observed a sudden increase in temperature in the middle of the paper sample at the end of the pressure pulse and attributed this to flashing. We speculated that the expanding steam displaced the unbound water and allowed heat to be convectively transferred from the top of the sheet to its lower portions. This mechanism was confirmed in the subsequent study in the flashing apparatus.
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