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Undersøkelse av raffinose oligosakkariders potensial til bruk i mat gjennom bioraffinering, fermentering og enzymatisk modifisering
Full text linkInterest in pulses has increased in recent years. The focus is predominantly on the proteins and their functionality in food products while the carbohydrate fraction has received less attention. Part of this fraction are raffinose family oligosaccharides (RFOs), which are present up to 6 % of the dry weight in pulses. Humans are however unable to digest RFOs and they therefore pass through the small intestine to the lower digestive tract, where they are readily fermented by bacteria. This classifies them as fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) as they cause symptoms such as bloating, nausea or diarrhoea in many consumers. For people with gastrointestinal conditions, such as irritable bowel syndrome (IBS), it is therefore often recommended to omit these carbohydrates from their diet. In healthy consumers on the other hand, RFOs can also stimulate growth of beneficial bacteria, i.e. they can have prebiotic effects. This thesis argues that RFOs can be exploited for value-added use through modern biorefining, fermentation and enzyme technologies.
Therefore, in Paper 1 an industrially feasible biorefining process was developed to isolate RFOs from pulse protein concentrates available on the Scandinavian market. It could be shown that by using scalable process equipment, water and moderately acidic pH, the production of 1 kg carbohydrate-enriched extract per 10 kg of concentrate from faba beans or peas can be achieved. RFO content in the extract varied between faba beans and peas (30-50 % RFO), yet protein fractions were RFO-reduced by 70-90 % and increased in protein content (+5-6 %). This process therefore creates a more valuable protein extract (more protein, fewer FODMAPs) and a carbohydrate stream that can serve as a resource for further food production or beyond.
To test this, Paper 2 investigated fermentations, specifically the potential to selectively stimulate growth of desired microorganisms in food products and the influence on sensory properties. A total of 14 lactic acid bacteria were screened for growth with RFO extract from Paper I in media and in beer with stressors presents (alcohol, α-acids). From this screening, three bacteria (Lactobacillus sp., Lactococcus sp.) were selected to brew sour beers in co-culture with yeast (Brettanomyces sp.) and RFOs. Via chromatography, it was shown that the selected bacteria consumed RFOs, and both acids and other metabolites increased in concentration within only three weeks. A trained sensory panel compared the sour beers made with RFO extract with a traditional Belgian sour beer and negative controls (no RFOs) and found that many sensory attributes were affected by RFO addition. Several parameters of RFO beers were comparable to the commercial product, for which the production process typically takes years. Beany taste, which is commonly associated with peas, did however not increase through RFO addition and was even lower than in the Belgian beer (made without pulses).
In Paper 3 enzymatic modifications were investigated as a second biotechnological approach to utilize RFOs. Lactose and sucrose are commonly used in the enzymatic production of prebiotic oligosaccharides. For raffinose, this potential is however underexplored. Therefore, we combined RFOs with lactose and the established transglycosylating enzyme BgaD-D from Niallia circulans. This generated new-to-nature oligosaccharides, that were hypothesized to be fermentable by fewer microorganisms, which could reduce FODMAP-associated gastrointestinal symptoms in consumers. Reactions showed RFOs as suitable acceptors and reaction characteristics were comparable to lactose alone. Through nuclear magnetic resonance (NMR) spectroscopy analysis, structures were identified, majorly being galactosyl-(β1-4)-RFOs. These reaction products were then subjected to a fermentability screening with 12 bacteria relevant to food and gut. Results indicated reduced fermentability by some of the selected strains, whilst the commensal gut bacteria Bacteroides sp. seemingly grew unaffected. This showed the potential of RFOs as substrate for enzymatic synthesis and indicated that this has the potential to mitigate some of the undesired effects of RFOs in the human diet.
Overall, this research demonstrated that notable amounts of RFOs can be extracted from readily available feedstocks and that they can serve as a starting point for utilization towards food products and ingredients. This reduces side streams from food production, could expand the groups of consumers otherwise refraining from pulses and moreover creates new possibilities for companies already producing pulse derived ingredients.Interessen for belgvekster har økt i de siste årene og forskning og utvikling har fokusert mye på proteiner og deres funksjon i mat produkter. Karbohydratene i belgvekster har samtidig fått mindre oppmerksomhet. En av karbohydrattypene i belgvekster er raffinose oligosakkarider (RFOs), som utgjør opp mot 6 % av frøet. Mennesker er ikke i stand til å bryte ned disse oligosakkaridene selv og derfor havner de i tykktarmen hvor mikroorganismer nyttiggjør seg av dem. Dette er grunnlaget for at RFOs kategoriseres som FODMAPs (fermenterbare oligo-, di- og monosakkarider og sukkeralkoholer) og at de ved inntak kan forårsake negative symptomer hos mennesker som oppblåsthet, kvalme og diaré. Mennesker med fordøyelsessykdom som IBS (irritabel tarm syndrom) er ofte anbefalt å unngå disse i kostholdet sitt. For sunne mennesker kan slike oligosakkarider derimot stimulere til vekst av gunstige tarmbakterier som gir positive helseeffekter, og disse karbohydratforbindelsene kan da klassifiseres som prebiotika. Hypotesen i denne avhandlingen er at det er mulig å utnytte RFOs bedre enn det gjøres i dag og at dette kan gjøres ved å bruke moderne bioraffinerings-, fermenterings- og enzymteknologier.
I det første arbeidet (manuskript 1) ble det utviklet en industrianvendelig bioraffinerings prosess for å isolere RFOs fra protein konsentrater fra nordiske belgvekster. Studien viste, at ved å bruke skalerbart utstyr og vann med noe redusert pH, kan man produsere 1 kg med RFO-ekstrakt per 10 kg proteinkonsentrat. RFO innholdet i ekstraktet varierte mellom åkerbønner og erter (30-50% RFOs), men den opprinnelige protein fraksjonen fikk likevel redusert RFO inneholdet med 70-90 % og fikk samtidig et noe høyere protein innehold (+5-6 %) enn ved startpunktet. Prosessen skaper dermed en mer verdifull proteinfraksjon (mer protein, mindre FODMAPs), samtidig som karbohydratene som fjernes kan brukes videre til å lage andre mat produkter, prebiotika og ingredienser.
For å teste mulige anvendelser ble det i manuskriptet 2 undersøkt om hvordan RFO ekstraktene kan stimulere vekst av ønskede melkesyrebakterier i fermenterte mat produkter og samtidig hvordan sensoriske egenskaper blir påvirket. 14 bakteriestammer ble testet for vekst på RFOs isolert fra arbeidet med manuskript 1 i både generelle vekstkultur media og øl hvor veksthemmende substanser (etanol, humle) er til stede. Etter screeningen ble tre stammer (to Lactobacillus og en Lactococcus) valgt for å produsere to typer surøl med RFOs og gjær (Brettanomyces) i co-kulturer. Kromatografisk analyse av produktene viste at bakteriene omsatte RFOs og at konsentrasjon av syrer og andre metabolitter økte innen tre uker. I tillegg sammenlignet et trent smakspanel de RFObaserte surølene med et tradisjonelt belgisk surøl, samt kontroll-øl uten RFOs. Panelet fant at RFO tilsetning økte flere smakskarakteristikker og at noen av dem er sammenlignbare med belgisk øl som trenger flere år å produseres. Spennende nok, økte RFO tilsetning ikke smak av bønner, ofte et problem med ingredienser fra belgvekst, og det belgisk ølet smakte ifølge den sensoriske testen mest av bønner.
I manuskript 3 ble en annen bioteknologisk bruk av RFOs undersøkt: Enzymatisk modifisering. Bruk av laktose og sukrose er vanlig for å produsere prebiotiske oligosakkarider gjennom enzymatisk transglykosylering. Her er potensiale til RFOs mindre utforska. Derfor brukte studien RFOs sammen med laktose og det velkjente enzymet BgaD-D fra Niallia circulans til å produsere nye typer oligsakkarider med flere ulike typer glykosidbindinger. Hypotesen er at disse er mindre fermenterbare av tarm bakteriene og dermed vil redusere de typiske symptomer av FODMAPs. Reaksjoner viste at RFOs fungerer som akseptor i transglykolyseringen og at viktige reaksjonsparameter ligner på de reaksjonene med laktose alene. Med NMR (kjernemagnetisk resonansspektroskopi) kunne produktene identifiseres og det ble vist at produktene hovedsakelig er av typen galactosyl-(β1-4)-RFO. Disse produktene ble deretter fermentert med 12 bakteriestammer som er relevante for mat og fordøyelse. Resultatene indikerer redusert fermenterbarhet av noen stammer, mens vekst av noen typiske tarmbakterier som er tilpasset vekst på komplekse glykaner (Bacteroides sp.) er tilnærmet upåvirket. Denne studien viste dermed potensiale for enzymatisk modifisering av RFOs til å redusere FODMAP symptomer. Oppsummert viser avhandlingen at betydelige mengder RFOs kan ekstraheres fra kommersielle råstoffer og at de kan fungere som utgangspunkt for å lage mat og ingredienser. Dette reduserer sidestrømmer fra matproduksjonen, kan bidra til forbedring av belgvekstprodukter til de av konsumentene som reagerer på RFOs og også utvide produksjonsmulighetene for industrien som produserer ingredienser som er basert på belgvekster
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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