| 1. |
- Andersson, Thorbjörn, et al.
(författare)
-
The effects of selected aldehydes, ketones and carboxylic acids on off-flavours in water
- 2005
-
Ingår i: International journal of food science & technology. - : Wiley InterScience. - 0950-5423 .- 1365-2621. ; 40:9, s. 993-1004
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of selected aldehydes, ketones and carboxylic acids on the development of off-flavours in water were studied. Combinations of hexanal, octanal, 2-octanone, 5-nonanone, hexanoic acid and nonanoic acid were rated by the off-flavour intensities they created in water at concentrations just at or below the threshold value of each analyte. Two different sensory panels evaluated the off-flavours induced by different combinations of the analytes. The observations of the two panels agreed well. From these studies, it could be concluded that aldehydes play an important role in the development of off-flavours intensities in water. There were synergistic effects between aldehydes and ketones, as well as between aldehydes and carboxylic acids. Small amounts of aldehydes and carboxylic acids – well below their respective threshold values – caused an increase in the off-flavour intensity. No synergism between ketones and carboxylic acids could be observed
|
|
| 2. |
- Brandén, Gunnar, 1985-, et al.
(författare)
-
39 000 anställningar till och med 2020 : en studie av rekryteringsbehovet i Västerbottens län
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sverige och Västerbotten befinner sig i en återhämtningsperiod sett till den ekonomiska och sysselsättningsmässiga utvecklingen. På medellång och lång sikt står Västerbotten, i likhet med flertalet andra län i Sverige, inför relativt stora utmaningar när det gäller matchningen mellan efterfrågan på och utbudet av arbetskraft. Mer specifikt kan detta beskrivas som en kompetensmatchningsutmaning, som i Västerbotten bland annat beror på en åldrande befolkning och en förändrad efterfrågan på arbetskraft med specifika kompetenser. Situationen innebär en påtaglig risk att vissa yrken, givet att utvecklingen fortsätter i den riktning som den gjort det senaste decenniet, kommer att uppleva kraftiga utbudsbrister eller omvänt en risk för överskott. Dessa scenarion reser ett antal viktiga frågor: Hur många inom olika yrken kommer att gå i pension? Vilka kompetenser kommer att behövas? Vilka branscher växer och vilka minskar? Hur klarar utbildningssystemet att svara mot arbetsmarknadens behov av kompetens? Kort sagt, hur kan kompetensförsörjningen förbättras så att regionen står väl rustad inför den framtida utvecklingen? Dessa och liknande frågor ska diskuteras och åtminstone delvis besvaras inom ramen för de regionala kompetensplattformar som på regeringens uppdrag etableras i respektive län. I Västerbottens län ansvarar Region Västerbotten för uppbyggnaden av den regionala kompetensplattformen.Syftet med de regionala kompetensplattformarna är att åstadkomma en ökad samverkan kring kompetensförsörjning och utbildningsplanering på kort och lång sikt. Arbetet ska leda till ökad kunskap, översikt och samordning inom kompetensförsörjnings- och utbildningsområdet. Uppdraget består av att dels utarbeta kunskapsunderlag och dels av att kommunicera dessa med arbetslivets företrädare och med utbildningsanordnare. Den föreliggande rapporten är en del i arbetet att skapa ett kvantitativt kunskapsbidrag kring framtida rekryteringsbehov i Västerbottens län.Rapportens tidshorisont sträcker sig till 2020 med ett nedslag 2015, där rekryteringsbehovet på medellång sikt beskrivs. Syftet med föreliggande rapport inbegriper att dels på ett mer generellt sätt beskriva Västerbottens arbetsmarknads- och branschstruktur, och dels belysa rekryteringsbehoven för respektive yrkesgrupp och bransch i länet. Särskilt fokus läggs vid branscher och yrken som härrör till turism, tillverkning och utvinning, företagstjänster, samt vård och omsorg. Rapporten skapar också ett underlag för att spegla näringslivets och arbetsmarknadens inneboende dynamik och förändring över tid.Sysselsättningsframskrivningarna utgår från den grundläggande frågeställningen kring regionalt utbud och efterfrågan på arbetskraft. Utbudet på arbetskraft bottnar i en individs beslut om arbetskraftsutbud, om individen skall arbeta och i sådant fall hur mycket. Detta beslut bestäms i stor utsträckning av individens syn på lönsamheten i att arbeta i termer av nytta. Deltagandet på den regionala arbetsmarknaden påverkas i sin tur av regionens efterfrågan på arbete. Värt att notera är att arbetskraftsutbudet inte alltid är den enskilde individens beslut, utan många gånger ett gemensamt val för hushållet.Efterfrågan på arbetskraft bestäms på kort sikt av arbetsgivarens beslut om hur många individer som ska anställas samt vilken kompetens som behövs utifrån ett lönsamhetsperspektiv. På lång sikt förklaras emellertid efterfrågan på arbetskraft i stor utsträckning av teknisk utveckling och internationell konkurrens. Den tekniska utvecklingen påverkar produktivitets- och produktutveckling, vilket på sikt förändrar branschers relativa positioner och efterfrågan på olika typer av arbetskraft. Intåget av datorer i produktion och organisation är ett tydligt exempel som förändrat både produktion och produkt samt vilken typ och kvantitet av arbetskraft som efterfrågas. I sammanhanget kan detta också ses som en del av den pågående strukturförändringen i den svenska ekonomin.Strukturella förändringar innebär en förskjutning av ekonomisk verksamhet mellan och inom ekonomins olika sektorer och påverkar vilken typ av arbetskraft som efterfrågas. Från 1970-talet pågår i Sverige en utveckling som innebär att tjänstesektorns relativa storlek ökar och industrisektorn minskar. Också inom respektive sektor pågår en påtaglig utveckling, där exempelvis innehållet i en tjänst eller produkt för 5-10 år sedan i många fall inte alls är jämförbart med dagens innehåll. Tredimensionella biografvisningar och mobiltelefonapplikationer utgör tydliga exempel på detta. Samtidigt utvecklas industrisektorn mot en allt mer högproduktiv produktion som innefattar ett allt större kunskapsinnehåll. Strukturomvandling och förskjutningar inom näringslivet tydliggör det faktum att den kompetens som efterfrågas av arbetsmarknaden ständigt förändras och understryker därför behovet av en kontinuerlig matchningsprocess.
|
|
| 3. |
- Forsgren, Gunnar, 1963-, et al.
(författare)
-
Analysis of volatile compounds of aqueous thyme solutions by headspace gas chromatography, gas sensor arrays ("electronic nose") and a sensory odour panel
- 2010
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The ability of a commercial emission analysis system to evaluate a sensory related attribute was investigated. Since food applications are very complex, a simplified model system consisting of aqueous thyme solutions was evaluated. Sensory odour assessments were made as well as instrumental analysis applying the emission analyser, based on gas sensor arrays, (a so called electronic nose) and headspace gas chromatography. The operation of the emission analyser was found critical and could be optimised thanks to the detailed chemical information obtained by the chromatography. This information also guided a proper evaluation of the emission analyser raw data and predictions of the relative thyme concentrations of the solutions. In that way the emission analyser separated the thyme solutions even better than the assessors applying sensory odour analysis. Since the results seem encouraging the strategy developed and knowledge gained may well be used for investigating more complex systems closer to real applications.
|
|
| 4. |
- Forsgren, Gunnar, 1963-
(författare)
-
Evaluation of volatile organic compounds related to board based packaging by use of instrumental and sensory analysis
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main topic of the thesis is characterisation and evaluation of volatile organic compounds emitted by packaging materials based on paperboard products. The properties and concentration of these compounds are critical to how well these materials perform when applied as a main component of food packaging. Specifically there is an interest for finding out whether the materials are neutral enough from a flavour and odour perspective. This means that the odour and flavour of the packed foodstuff must not be influenced in a nonacceptable way by the packaging.The studies may be seen as divided into two main parts complemented with an additional study. In the first part ”Electronic noses”, based on quite a number of gas sensors of different sensitivity profiles, conventional gas chromatography and to some extent also sensory analysis were applied for evaluating the volatile organic compounds emitted from paperboard products. The results obtained from the ”electronic nose” measurements were evaluated in the light of the detailed chemical information provided by the gas chromatography. First a large number of paperboard products were analysed followed by analysis of some thirty sequential jumbo reels of two different board products. The obtained results clarified what could be achieved when applying the gas sensor based analytical system to this type of materials. Furthermore the experiences gained by the experiments pointed out the importance of managing sample handling, headspace generation and gas flow distribution in a good way. These findings were useful for managing a third experimental series in which a commercial gas sensor based system was applied for differentiating aqueous thyme solutions regarding the thyme concentrations.The multivariate data analysis methodology used for evaluating the gas sensor responses was successfully applied also to the obtained gas chromatography data. The chosen approach was to treat the chromatograms as having been generated by a large number of sensors. The sensory analysis was applied for investigating whether the found differences were relevant from a taint perspective which was invaluable since the ”electronic nose” system and our human chemical senses work according to different principles. It was therefore especially interesting to find out that the “electronic nose” and off-flavour differentiation between sequential jumbo reels of one product agreed well. Furthermore it was clearly not just a matter of different humidity of the materials.In the second part the sensory analysis was the mainly applied evaluation technique. Gas chromatography was very valuable for supporting the experimental work and contributing to the understanding of the results whereas no gas sensor related evaluations were performed. In the first part a need for investigating a number of issues more carefully was pointed out. Topics such as sensory sensitivity, perception of mixtures in relation to the mixture components and calibration of sensory analysis were consequently investigated. For managing it was necessary to restrict the studies to simplified model systems that were arranged based on results and experiences obtained from studies of real packaging systems. The results pointed out the complexity of sensory related packaging issues and help in improving these type of sensory analysis e.g. by suggesting calibration procedures. The additional study is related to active packaging which means that the intention with the packaging is to influence the packed foodstuff in a way that is favourable and desired. In this study odorants were added to dispersion coatings that well could be used in the paperboard products. Headspace gas chromatography was successively applied for measuring the amounts and coating retention of the odorants upon drying. Furthermore multivariate data analysis was useful for overviewing the results and finding relations and structures that otherwise were hard to see.
|
|
| 5. |
- Forsgren, Gunnar, 1963-, et al.
(författare)
-
Flavour interactions in aqueous solutions of an aldehyde, a ketone and a carboxylic acid
- 2009
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Flavour impressions of aqueous solutions of nonanoic acid, octan-2-one and octanal were investigated. In a pre-study, the psychophysical functions of single component solutions were estimated and good agreements to Fechner’s law were obtained. The findings guided the choice of concentrations used in the main flavour interaction study. In this study, binary mixture interactions of nonanoic acid – octanal and octan-2-one – octanal were investigated in terms of perceived intensity and quality. Ten assessors judged the mixture solutions for flavour intensity by applying a free magnitude estimation procedure and describing their perceived quality impressions. The five assessors who were able to describe the perceived qualities in a consistent and logic way considered both mixtures being heterogeneous. Only three assessors scored intensities of the included single component solutions well in agreement with Fechner’s law. These three assessors’ intensity scorings of the mixtures did not deviate from those of a hypothetic additive model in a clear way. The intensity scorings of most of the other assessors were strongly dominated by one of the two components whereas some assessor did not score systematic at all.
|
|
| 6. |
- Forsgren, Gunnar, 1963-, et al.
(författare)
-
Identification of carton board qualities using gas chromatography or gas sensitive sensors in combination with multivariate data analysis
- 1997
-
Ingår i: Nordic Pulp and Paper Research Journal. - Stockholm. - 0283-2631. ; 12:4, s. 276-281
-
Tidskriftsartikel (refereegranskat)abstract
- Headspace gas chromatograms of 40 different food packaging board and paper qualities, containing in total 8167 detected peaks, were processed with principal component analysis. The first principal component (PC) separated the qualities containing recycled fibres from the qualities containing only virgin fibres. The second PC was strongly influenced by peaks representing volatile compounds from coating and the third PC was influemced by the type of pulp used as raw material.The same 40 board and paper samples were also analysed with also called electronic nose which essentially consists of a selection of gas sensitive sensors and a software based on multivariate data analysis. The electronic nose showed to have a potential to distinguish between qualities from different mills although the experimental condition were not fully developed.The capability of the two techniques to recognise "fingerprints" of compounds emitted from board and paper suggests that the techniques can be developedfurther to partly replace human sensory panels in the quality control of paper and board intended for food packaging materials.
|
|
| 7. |
|
|
| 8. |
- Forsgren, Gunnar, 1963-, et al.
(författare)
-
Towards Improved Comparability of Off-flavour Measurements of Packaging Materials
- 2009
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Since one task of packaging in direct contact with food is to preserve flavour, it is important to determine to what extent packaging materials can evoke off-flavours in packed foodstuffs. The generated results may be expressed in terms of intensity, using quantitative measures, and quality, using qualitative descriptors. A maximum off-flavour impact is not seldom specified for paperboard packaging materials. Such specifications would make little sense unless they were comparable to those of other products. For this reason, it is important to develop calibration procedures and to identify critical points for the applied analytical methods. A procedure based on matching the off-flavour intensities of real packaging materials with those of simplified calibration samples has been developed. Defining the concentrations of calibration samples that correspond to actual intensity numbers makes more uniform and comparable quantification possible. The present study examines the difference between real paperboard products and such calibration samples. It also demonstrates that sensory detection ability depends on food simulant characteristics by determining the flavour-detection thresholds of one odorant present in either of two food simulants. The sorption capacities and retention abilities of the food simulants for this odorant were investigated using headspace gas chromatography. The threshold determination identified calibration sample concentrations corresponding to just noticeable off-flavours and verified that a sufficiently large number of trained assessors is needed to conduct such sensory analysis. The sensitivity of different food simulants to off-flavour contamination was also examined.
|
|
| 9. |
- Forsgren, Lilian, 1990, et al.
(författare)
-
Composites with surface-grafted cellulose nanocrystals (CNC)
- 2019
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 54:4, s. 3009-3022
-
Tidskriftsartikel (refereegranskat)abstract
- Hydroxyazetidinium salts were used to surface-modify cellulose nanocrystals (CNC) by grafting the salts onto the sulphate ester groups on the CNC surfaces. The grafting was confirmed by ζ-potential measurements and by the thermal degradation behaviour of the modified CNC. The thermal stability (onset of degradation) of the CNC was improved by the surface modification (almost 100 °C). Composites containing surface-modified or unmodified CNC (0.1, 1.0 and 10 wt%) with an ethylene-based copolymer as matrix were produced by compression moulding. The thermal stability of the composites was not, however, markedly improved by the surface grafting onto the CNC. It is suggested that this is due to a degrafting mechanism, associated with the alkaline character of the system, taking place at high temperatures. Model experiments indicated, however, that this did not occur at the conditions under which the composites were produced. Furthermore, in the case of a reference based on pH-neutralised polymeric system and modified CNC, an upward shift in the onset of thermal degradation of the composite was observed. The addition of the CNC to the polymer matrix had a strong influence of the mechanical performance. For example, the tensile modulus increased approximately three times for some systems when adding 10 wt% CNC. The surface grafting of the hydroxyazetidinium salts appeared mainly to affect, in a positive sense, the yield behaviour and ductility of the composites. The results of the mechanical testing are discussed in terms of interactions between the grafted units and the matrix material and between the grafted groups.
|
|
| 10. |
- Forsgren, Lilian, 1990, et al.
(författare)
-
Water-assisted extrusion and injection moulding of composites with surface-grafted cellulose nanocrystals – An upscaling study
- 2021
-
Ingår i: Composites Part B: Engineering. - : Elsevier BV. - 1359-8368. ; 208
-
Tidskriftsartikel (refereegranskat)abstract
- The large-scale surface modification of cellulose nanocrystals (CNC) was carried out to produce CNC-containing composites, in a scale of 3 kg, using industrial-scale melt processing techniques such as twin-screw extrusion and injection moulding. Two different polymer matrices, ethylene-acrylic acid copolymer (EAA) and low-density polyethylene (LDPE), were reinforced with 10 wt% unmodified cellulose nanocrystals (CNC) or surface-treated CNC, where a 2-hydroxyproyl-N-diallyl group had been grafted onto the sulphate half-ester groups on the CNC surfaces. This was achieved by mixing an aqueous CNC dispersion and the polymer pellets directly in the twin-screw extruder followed by a second dry compounding step prior to shaping by injection moulding. The injection-moulded materials were characterized with respect to their mechanical properties and thermal stability. The addition of 10 wt % CNC resulted in all cases in an increase in the yield strength and stiffness by 50–100%, most significantly for the EAA based composites. There were indications of the presence of a stable interphase and a percolating network in the EAA-based materials, according to dynamic-mechanical measurements. A reduction in thermal stability was observed for the melt-processed samples containing diallyl-modified CNC and discoloration in the EAA based samples.
|
|
