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Ohran ja kauran folaatit ja folaatin luontainen lisääminen ohraa ja kauraa prosessoimalla
Full text linkFolate, one of the B vitamins, has a well-established role in preventing neural tube defects (NTDs) in the developing foetus and megaloblastic anaemia. Folate intake is below recommended levels, especially in countries where mandatory folic acid fortification is not practiced. In these countries, interest to innovate ways for the natural enhancement of folate is high. Wholegrain cereals provide a high proportion of natural folate. Oats and barley have once again attracted attention as cereals with health potential due to their high beta-glucan contents. However, knowledge on the folate content in oats and barley and their milling fractions is limited. In turn, several microbes are potential folate producers in aqueous processes. Folate content in cereal-based products could be further improved by utilising folate-rich milling fractions or by using the ability of microbes to synthesise folate.
In this thesis, oats and barley were studied as sources of folate. The total folate was determined in five oat and barley cultivars over three years with a microbiological method. Different fractions were produced from oats by oat processing and from barley by scarification and industrial milling. The folate vitamer distribution in fractions was examined with the ultra-high performance liquid chromatography (UHPLC) method. Furthermore, bacteria isolated from cereal products, food-grade yeasts and lactic acid bacteria (LAB) were studied for their folate-production in rich medium and in aqueous processes of oat and barley bran and flour. In addition, the profile of the produced folate vitamers was studied in rich medium and in oat flour and barley bran matrices. The validated UHPLC method proved to be fast and sensitive for determining seven folate vitamers in cereal and microbe samples. New data was obtained on the folate content and its variation in oat and barley cultivars. The total folate content in barley grains was slightly higher at 770 ng/g dm, than the folate content in oats (690 ng/g dm) when determined shortly after harvest. These contents were higher than had been previously found in wheat. In addition, the variation among the cultivars in each year was moderate. This study also showed that oat and barley grains might lose folate during storage. Dry-fractionation of oats and barley yielded fractions with high folate content. Among the oat fractions, the highest folate content was found in its by-products. The folate content in the residual flour from oat flaking was 2.5-fold that of native oat grain. In barley grain 40 60% of the folate was lost during industrial dehulling and pearling processes. The total folate content in oat and barley fractions demonstrated that folate was localised in the outer layers and germ. The main folate vitamers in the oat and barley fractions were 5-methyltetrahydrofolate, 5-formyltetrahydrofolate and 5,10-methenyltetrahydrofolate.
A few endogenous bacteria isolated from oat bran produced folate in rich medium more than Saccharomyces cerevisiae, which is known as a good folate producer. In cereal matrices, several food-grade yeasts produced a significant amount of folate with glucose addition, but folate production by LAB was low. Folate content in the oat flour matrix fermented with Pseudomonas sp. for 24 h and stored for 2 weeks in the cold was 9-fold that of the control sample. Bacteria and yeasts accumulated the most 5-methyltetrahydrofolate followed by tetrahydrofolate and 5,10-methenyltetrahydrofolate. The results in this thesis show that oats and barley are good sources of folate. Introducing folate-rich milling fractions into cereal products would increase the folate intake of consumers. Further, food-grade yeasts and bacteria have potential for folate enhancement in aqueous cereal processing. Particularly, the folate production by some cereal-based endogenous bacteria offers possibilities for natural folate enrichment in beta-glucan-rich oat and barley matrices.Folaatit ovat vesiliukoisia B-vitamiiniyhdisteitä, joita tarvitaan yhden hiiliyksikön siirtoreaktioissa DNA:n ja RNA:n synteesissä sekä aminohappoaineenvaihdunnassa. Folaatti esiintyy luonnossa monina eri muotoina. Foolihappo on synteettisesti valmistettu, biologisesti aktiivinen folaattimuoto, jota käytetään farmaseuttisissa valmisteissa ja elintarvikkeiden rikastamisessa. Riittämätön folaatin saanti aiheuttaa megaloblastista anemiaa sekä raskauden varhaisvaiheessa sikiön hermostoputken sulkeutumishäiriöitä. Lisäksi vähäisellä folaatin saannilla on todettu olevan yhteys lisääntyneeseen riskiin sairastua tiettyihin syöpätyyppeihin, sydän- ja verisuonitauteihin ja muistisairauksiin. Folaatin saanti jää alle suositusten Suomessa ja useissa muissakin Euroopan maissa, joissa lainsäädäntö ei velvoita lisäämään foolihappoa vehnäjauhoihin.
Suomessa noin lähes kolmasosa folaatista saadaan vilja- ja leipomotuotteista, mutta niiden folaattipitoisuuksia voitaisiin kuitenkin yhä lisätä. Ohran ja kauran elintarvikekäyttöä kannattaisi suosia niiden sisältämien bioaktiivisten yhdisteiden ja osittain liukoisen kuidun, beeta-glukaanin takia. Aikaisemmin on todettu, että vehnän ja rukiin jyvän uloimmat kerrokset, ns. lesekerrokset, sisältävät paljon bioaktiivisia yhdisteitä. Ohran ja kauran folaateista on kuitenkin erittäin vähän tutkimustietoa. Luontaisen folaatin tuottamiseen voitaisiin käyttää myös mikrobeja, sillä tietyt bakteerit ja hiivat syntetisoivat folaattia sopivissa kasvatusolosuhteissa.
Tämän väitöskirjatutkimuksen tavoitteena oli tutkia ohraa ja kauraa folaatin lähteinä sekä selvittää, miten ohra- ja kauratuotteiden folaattipitoisuuksia voitaisiin lisätä luontaisesti. Aluksi erittäin suuren erotuskyvyn nestekromatografinen erotusmenetelmä (UHPLC) optimoitiin soveltuvaksi viljamateriaalin eri folaattimuotojen tutkimiseen. Tämän jälkeen määritettiin kaura- ja ohralajikkeiden folaattipitoisuudet kolmelta eri satokaudelta. Lisäksi selvitettiin, mihin jauhatusjakeisiin folaatit ovat rikastuneet ohran ja kauran jyvissä. Tutkimuksen toisessa osassa tutkittiin viljassa luontaisesti esiintyvien bakteereiden ja muualta eristettyjen hiivojen ja bakteereiden folaatin tuottoa synteettisessä kasvatusalustassa. Lopuksi ohran ja kauran vesiseoksia, puuroja, fermentoitiin folaattia tuottavilla mikrobeilla, joilla ei ollut todettu beeta-glukaanin rakennetta hajottavaa entsyymiaktiivisuutta.
UHPLC-menetelmä määritti nopeasti ja luotettavasti eri folaattimuodot viljamateriaalista. Sillä saatujen tulosten vastaavuus mikrobiologisen menetelmän tuloksiin oli parempi kuin aikaisemmissa tutkimuksissa. Ohra ja kaura osoittautuivat hyviksi folaatin lähteiksi. Keskimäärin tuore, kuorimaton kokojyväohra sisälsi hieman enemmän folaattia (770 ng/g kuiva-ainetta kohden) kuin kuorimaton kokojyväkaura (690 ng/g) mutta sekä ohrassa että kaurassa folaattia oli hieman enemmän kuin vehnässä. Kun eri ohra- ja kauralajikkeiden folaattipitoisuuksia verrattiin satokausittain toisiinsa, voitiin tunnistaa lajikkeita, joiden folaattipitoisuus oli joka vuosi suurin tai pienin verrattuna muihin lajikkeisiin. Lisäksi todettiin, että normaalin, 2 3 vuoden varastoinnin aikana jyvät menettävät osan folaatistaan. Ohran ja kauran jyvien myllytys tuotti folaattirikkaita jakeita. Folaatti on ohran ja kauran jyvissä rikastuneena jyvän uloimpiin kerroksiin ja alkioon. Tietyt ohran jauhatusjakeet sisälsivät 5 kertaa enemmän folaattia kuin kuluttajille tarjottava ohrajauho. Lisäksi osoitettiin, että ohran teollisessa kuorikerrosten hionnassa menetetään 40 60 % hiomattoman kokojyväohran folaateista. Erityisen paljon folaattia oli myös kauran hiutaloinnissa syntyvässä jäännösjauhossa. Ohran ja kauran folaatti oli pääasiassa 5- metyylitetrahydro-, 5-formyylitetrahydro- ja 5,10-metenyylitetrahydrofolaattina.
Hiivat tuottivat folaattia huomattavia määriä ohra- ja kaurapuuroissa, joihin oli lisätty glukoosia. Muutamat viljatuotteista eristetyt bakteerit osoittautuivat kuitenkin tehokkaammiksi folaatintuottajiksi kuin hyväksi tuottajaksi todettu leivinhiiva. Kaurakuidusta eristetty Pseudomonas sp. tuotti folaattia kaurapuurossa niin, että puuron folaattipitoisuus fermentoinnin ja kylmäsäilytyksen jälkeen oli yhdeksänkertainen verrattuna käsittelemättömään näytteeseen. Sen sijaan maitohappobakteereiden folaatin tuotto puuroissa oli vähäistä. Bakteerit ja hiivat tuottivat pääasiassa 5-metyylitetrahydro- ja tetrahydrofolaattia.
Tämän väitöskirjatyön tulokset osoittavat, että ohra ja kaura ovat hyviä folaatin lähteitä. Niiden folaattirikkaita jauhatusjakeita voitaisiin lisätä leivontaominaisuuksien sallimissa rajoissa viljatuotteisiin, jolloin kuluttajien päivittäinen folaatin saanti paranisi. Lisäksi tutkimus selvitti, että tietyt elintarvikkeista eristetyt hiivat ja viljaperäiset bakteerit ovat erityisen hyviä folaatin tuottajia. Niitä voitaisiin hyödyntää viljapohjaisten, nestemäisten elintarvikkeiden tuotekehityksessä, kun halutaan yhdistää folaatin ja beeta-glukaanin terveyttä edistävät vaikutukset.ei saavutettav
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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
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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
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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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