Browsing by Subject "kaura"

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  • Lassi, Juho (Helsingin yliopisto, 2020)
    Oat (Avena Sativa L.) has been second most cultivated crop in Finland. Oat has been Finland’s most exported grain for several years and its use for human consumption has increased because of dietary benefits. Oat is well suited for northern growing conditions and there has been long tradition for oat breeding in Finland. High yield has been important breeding goal but because the new use purposes, also other quality parameters have more attention in breeding. According to statistics, the average oat yield was 3293 kg/ha in years 2002-2016. The average yields have not changed in past 15 years in farm level. Yield and quality formation of four Finnish oat varieties (Iiris, Meeri, Niklas ja Steinar) and two Central-European oat varieties (Canyon and Harmony) was studied during growing season 2016. The field experiment was carried out at Elimäki in southern Finland. Different characteristics were measured and calculated during the growing season. Dry matter accumulation, growing rhythm, lodging and plant height were determined. Also yield, harvest index, grain filling rate, grading, thousand kernel weight and other quality parameters were determined. Suitability for milling use were studied from the oat varieties. Study was conducted in field as a completely randomized plot experiment with three replicants. Number of growing days correlated positively with yield. The last maturated varieties, Canyon, Harmony and Iiris, produced highest yield and best quality. These highest yielding varieties did not thoug have the highest harvest index. Length of grain filling period correlated positively with thousand kernel weight and grading result which all are also important quality features for oat milling industry. A correlation between grain size and hectoliter weight was not observed in this study.
  • Lipping, Sanna (Helsingin yliopisto, 2021)
    Kaivannaisfosfori on merkittävin fosfaattilannoitteiden lähde maailman maataloudessa. Fosforia on kuitenkin rajallinen määrä maapallolla ja kaivannaisfosforin varannot uhkaavat ehtyä 50-500 vuoden aikana. Maailman maatalous joutuu sopeutumaan tulevaisuudessa kaivannaisfosforin vähenemiseen, jolloin fosforin talteen saaminen erilaisin kierrätysmenetelmin tulee olemaan merkittävä kiertotalouden osa. Kierrätyslannoitteiden mahdollisuuksia on yleisesti tutkittu viime aikoina paljon, mutta niiden vaikutusta kauran fosforin ottoon on tutkittu melko vähän. Tämän tutkimuksen tarkastelun kohteena oli kauran (Avena sativa. L Obelix) fosforin otto vuosina 2017 ja 2018 Uudellamaalla sijaitsevalla koelohkolla. Tutkittavina kierrätyslannoitteina olivat lihaluujauho, matokomposti, mädätejäännös ja ammoniumsulfaatti. Kontrollina tutkimuksessa olivat väkilannoiteruutu sekä lannoittamaton ruutu. Koepellon lannoitushistoria oli suomalaisittain tyypillinen ja pellon fosforitaso oli tutkimuksen alkuvaiheessa luokiteltu hyväksi tai korkeaksi. Vuoden 2017 kasvukausi oli pitkäaikaiseen keskiarvoon (1981-2010) nähden kylmä ja sateinen, kun taas vuosi 2018 oli erityisen lämmin ja kuiva. Tämän tutkimuksen perusteella näillä kierrätyslannoitteilla ei ollut merkitsevää eroa kauran fosforin ottoon kumpanakaan vuonna verrattuna väkilannoitteeseen tai lannoittamattomaan käsittelyyn. Merkitsevä ero näkyi kuitenkin vuoden 2017 fosforin otossa lihaluujauhon ja mädätejäännöksen välillä (p=0,0159 vertailussa lannoittamattoman käsittelyn ja p=0,0206 vertailussa väkilannoitekäsittelyn kanssa). Maaperän fosforitaseissa ei havaittu merkitseviä eroja käsittelyiden välillä. Kierrätyslannoitekäsittelyiden välillä havaittiin merkitsevä ero niiden vaikutuksessa maaperän pH-arvoon (p=0,045 vertailussa lannoittamattoman ruudun ja p=0,036 vertailussa väkilannoitekäsittelyn kanssa) vuonna 2018. Tukeyn HSD-testissä ei kuitenkaan tapahtunut jakaantumista eri alajoukkoihin. Koepellon ennestään hyvä ravinnetilanne on voinut vaikuttaa kokeessa tasaamalla eroja eri käsittelyiden välillä.
  • Hämäläinen, Katariina (Helsingin yliopisto, 2018)
    Biohiili on hiilipitoinen maanparannusaine, joka on valmistettu eloperäisestä aineesta pyrolyysimenetelmällä. Biohiilen sisältämä hiili on erittäin pysyvässä muodossa, mikä mahdollistaa hiilen sitomisen maaperään pitkäksi ajaksi. Joidenkin biohiilten on osoitettu parantavan maaperän rakennetta sekä veden ja ravinteiden saatavuutta tietyissä olosuhteissa, erityisesti tropiikin vähähiilipitoisilla ja happamilla mailla. Tässä tutkimuksessa selvitettiin kuusipohjaisen biohiilen vaikutuksia maaperän veden ja ravinteiden saatavuuteen sekä niiden vaikutuksia kauran (Avena sativa L.) satokomponentteihin viisi vuotta biohiililisäyksen jälkeen. Tutkimuksessa oli mukana biohiilen lisäksi lannoituskäsittelyiden vaikutus ja näiden kahden yhdysvaikutus. Biohiiltä oli lisätty koeruuduille vuonna 2011 tasoilla 0, 5, 10, 20 ja 30 t ha-1. Lannoituskäsittelyinä toimivat lannoittamaton kontrolli, mineraalilannoitus ja lihaluujauholannoitus. Biohiili vaikutti korkeimmalla lisäystasolla maaperän hiilen määrään tilastollisesti merkitsevästi. Biohiili ei vaikuttanut merkitsevästi maaperän kosteus- ja ravinneolosuhteisiin tai kauran satokomponentteihin. Lannoituskäsittelyllä oli merkitsevä vaikutus maaperän kosteuteen, ravinnepitoisuuksiin, johtolukuun, pH-arvoon, kasvuston lehtialaindeksiin, hiili/typpisuhteeseen, biomassaan sekä tuhannen jyvän painoon. Biohiili- ja lannoituskäsittelyillä ei havaittu olevan merkitseviä yhdysvaikutuksia mitattujen parametrien osalta. Tulokset voivat johtua maaperän lähtökohtaisesta korkeasta hiilipitoisuudesta, ja viisi vuotta sitten lisätyn biohiilen siirtymästä syvemmälle maahan, jolloin sen vaikutukset maaperän ominaisuuksiin ja kauran sadontuotantokykyyn ovat pienet. Lisäksi alkukevään 2016 runsaan tuomikirvaesiintymän levittämä kääpiökasvuviroosi heikensi kauran kasvua, minkä vuoksi mitattava sato jäi vähäiseksi. Biohiilen edut tulevat parhaiten esille kuivilla, ravinneköyhillä, huonorakenteisilla ja alhaisen luontaisen hiilipitoisuuden vaivaamilla mailla. Biohiilellä ei todettu olevan negatiivisia vaikutuksia maaperän kosteusolosuhteisiin, ravinnemääriin tai kauran sadon määrään tässä tutkimuksessa. Biohiilen pitkäaikaisten vaikutusten tutkimusta maaperään ja viljelykasvien satokomponentteihin on tärkeää jatkaa edelleen.
  • Jaakkola, Jenni (Helsingfors universitet, 2015)
    The aim of this master’s thesis was to study the effects of flaking conditions on the quality properties of oat flakes and to simulate the flaking process in laboratory conditions. The review of literature deals with oat processing focusing on oat flaking and oat flake quality properties. The flaking process includes groats steaming and tempering, which plasticizes the groats when moisture is absorbed. Then the groats are flattened by a flaking roller mill. Increasing tempering temperature and time results in higher water absorption. Increasing tempering time also increases the amount of fines. Flake breakage in the process reduces the flake yield resulting in more costs. There are no published studies that evaluate the impact of steaming on flake quality properties. The aim of the experimental part of this thesis was to study the effects of flaking moisture on flake strength and quality. Kilned and unkilned groats were flaked in a laboratory-scale flaking machine. Laboratory-scale flaking was carried out with a standardized flake thickness 0,7-0,8 mm. In addition, the properties of five commercial oat flakes were analyzed. There was significant variation between the different commercial oat flakes in their both water hydration capacities and amount of fines. The results implied that flaking conditions have an effect to these flake quality properties. Oat flakes were significantly thicker with higher flaking moisture. The roll gap was tightened to produce the same flake thickness. Both the bulk density and the amount of fines decreased with higher flaking moistures. There were no significant changes in the pasting properties of flakes made of kilned groats compared to kilned groats. Increasing flaking moisture reduces the amount of fines. In addition, water absorption increased with high flaking moistures. Even a three-percent increase in flaking moisture improved the quality of oat flakes. Increasing flaking moisture in between 12-20 % had a beneficial effect on quality properties of oat flakes.
  • Blankenstein, Hanna (Helsingfors universitet, 2016)
    Tutkielman kirjallisuuskatsauksessa perehdyttiin kauraan ja härkäpapuun raaka-aineena. Lisäksi tutustuttiin intialaiseen riisistä ja mustasta linssistä fermentoinnin avulla valmistettuun idli-höyryleipään ja sen valmistusprosessiin. Tutkielman kokeellisen osan tavoitteena oli selvittää soveltuvatko kotimaiset kaura ja härkäpapu idlin valmistusprosessiin. Idlin raaka-aineet korvattiin osittain tai kokonaan kauralla ja härkäpavulla. Lisäksi tutkittiin heräteviljelmän käyttöä taikinan ja valmiin höyryleivän ominaisuuksien kannalta. Osa taikinoista fermentoitiin idlin valmistusprosessin mukaan spontaanisti ja osaan lisättiin startteriksi leivinhiivaa tai viiliä. Taikinoiden viskositeetit mitattiin ennen fermentointia. Fermentoitumista mitattiin taikinan tilavuuden muutoksen, pH:n ja happoluvun avulla. Höyryleivistä määritettiin paistohäviö, korkeus ja sisuksen kovuus heti sekä seitsemän vuorokauden säilytyksen jälkeen. Valmiiden höyryleipien ravintosisältö ja välttämättömien aminohappojen koostumus laskettiin perustuen kirjallisuusarvoihin. Härkäpapu-riisi- ja härkäpapu-kaura -taikinat fermentoituivat spontaanisti. Härkäpapu-riisi -taikina fermentoitui härkäpapu-kaura -taikinaa tehokkaammin. Härkäpapupitoisuus nosti molempien taikinoiden happolukua fermentoinnissa. Taikinaan lisättävällä viilillä tai leivinhiivalla voitiin säädellä taikinan tilavuutta, ja sitä kautta vaikuttaa höyryleivän tilavuuteen, huokoisuuteen ja kovuuteen. Härkäpavusta ja riisistä oli mahdollista valmistaa rakenteeltaan hyvä höyryleipä. Härkäpapu ja kaura tuottivat ominaisuuksiltaan erilaisen, rakenteeltaan ei-huokoisen ja tiiviin höyryleivän. Kauraa sisältävät höyryleivät säilyivät pehmeämpänä kuin riisiä sisältävät. Raaka-aineiden suhdetta muuttamalla saatiin aikaan erilaisia höyryleivän rakenteita höyryleivän proteiinilaatua heikentämättä. Lähes kaikki höyryleivät ylittivät FAO:n asettamat vertailuarvot välttämättömien aminohappojen määrissä. Idli-prosessilla fermentoidut kaura ja härkäpapu soveltuvat höyryleivän lisäksi myös muiden ravintoarvoiltaan laadukkaiden ruokavalmisteiden pohjaksi.
  • Alasmaa, Terhi (Helsingin yliopisto, 2017)
    Food trends and the prevalence of gluten-free diet have increased the use of oats in pastry in recent years. However, wheat has not been replaced by oats alone, substitutes are often mixtures containing buckwheat and potato starch, among others. The flour used for sponge cakes is weak wheat flour. Next to flour, the main raw materials for sponge cake are egg and sugar. Eggs produce an aerated structure of the cakes. The purpose of this study was to use as much oat as possible in sponge cake without losing the characteristic structure of the product. In the preliminary experiments, it was found that it was possible to replace wheat flour fully by oat endosperm. When the oat flour contained bran, the characteristics of the sponge cake changed significantly. Other preliminary tests were per-formed with the use of full oat flours with different particle size. Endosperm oat and whole oat flours were selected for a maturing time test to examine the effect of flour disintegra-tion on the finished product. Texture- and moisture measurements were performed. Prod-ucts of the same oat flour were also manufactured in production scale. Texture- and hu-midity measurements, as well as the changes over time were captured. In addition, a con-sumer test and a descriptive analysis of the products were carried out by a trained taste panel. The study showed that wheat flour can be replaced by oat endosperm or full oat flour with a particle size of about 390 μm. The results of the preliminary investigation showed that it is possible to produce a sponge cake with full oat flour with almost the same characteristics as the product has when made with wheat flour, only the oat product was perceived a little dryer. The sensory profile on full oat flour sponge cakes showed more brittleness, the addition of bran made the biscuits even more brittle. Longer maturing time improved the properties of the product in every flour type tested. The best way to replace wheat flour by oat is using only oat endosperm.
  • Aalto, Kaisa (Helsingin yliopisto, 2019)
    Kauran käyttö leivonnassa on kasvattanut suosiotaan viime vuosien aikana. Gluteenittomuuden takia 100 % kauraleivonta on kuitenkin haasteellista, sillä taikinan käsiteltävyys vaikeutuu sitkon puuttuessa. Oikeanlaisen taikinan konsistenssin saavuttamiseksi ja onnistuneen leivonnan kannalta on tärkeää tunnistaa kauran vedensidontakykyyn vaikuttavat tekijät. Tutkimuksessa tarkasteltiin eri kauralajikkeiden beetaglukaanipitoisuuden yhteyttä vedensidontaan. Tavoitteena oli myös vertailla eri kauralajikkeista tehtyjen taikinoiden konsistenssia ja valmiiden leipien rakenteellisia ja aistinvaraisia ominaisuuksia. Kokeellisessa osiossa tutkittiin viidestä eri kauralajikkeesta valmistettujen jauhojen ja hiutaleiden vedensidontaa ja siihen vaikuttavia tekijöitä. Taikinan konsistenssimittauksia ja leivontakokeita varten näytteistä valmistettiin kaksi erilaista taikinaa, joissa toisessa käytettiin pelkästään kaurajauhoja ja toisessa puolet kaurajauhoista korvattiin saman lajikkeen kaurahiutaleilla. Leivonnan onnistumiseksi taikinoissa käytettiin apuna psylliumia. Kaurajauhoista sekä kaurajauhoista ja -hiutaleista valmistettujen taikinoiden konsistenssia tutkittiin aineenkoestuslaitteella (Texture Analyzer) käänteisen ekstruusion avulla. Leivontakokeissa leivottiin palaleipiä, joiden rakenteellisten ominaisuuksien muutoksia seurattiin myös aineenkoestuslaitteen avulla (Texture Profile Analysis). Tulosten perusteella lajikkeen vaikutus kauran vedensidontakykyyn, konsistenssiin ja leivontatuloksiin oli suuri. Beetaglukaanipitoisuuden yhteys kaurajauhojen vedensidontakykyyn ei ollut selkeä, mutta kaurahiutaleiden vedensidonta suureni beetaglukaanipitoisuuden suuretessa. Kauralajikenäytteiden konsistenssi riippui monesta eri tekijästä. Suuri beetaglukaani- ja proteiinipitoisuus näkyi suurena taikinoiden konsistenssina. Kaurahiutaleita sisältävien taikinoiden konsistenssi oli suurempi kuin vain kaurajauhoja sisältävien taikinoiden. Suuri taikinan konsistenssi helpotti taikinan käsittelyä ja muokkaamista. Konsistenssin suuruudella ei ollut suoraa yhteyttä valmiiden leipien rakenteellisiin ominaisuuksiin. Muutokset leipien rakenteessa tapahtuivat kypsymisen aikana ja johtuivat todennäköisesti lajikkeiden erilaisista liisteröitymislämpötiloista ja tärkkelyksen käyttäytymisestä paiston aikana. Liisteröityneen kauran lisääminen taikinan joukkoon paransi leipien rakenteellisia ominaisuuksia ja säilymistä.
  • Lepistö, Liisa (Helsingfors universitet, 2015)
    The fast staling rate of different oat breads is a significant problem in the baking industry. The aim of this work was to examine whether native oat flours would form better bread crumb structure than heat-treated and flaked oat flours, and decrease the staling rate, including increase of firmness and crumbliness. The literature review considers oat composition and milling process (heat treatment), baking, oat baking and bread staling. In the experimental work, baking properties of native, heat treated and flaked oat flour (51 % of flour) with wheat flour (49 % of flour) were measured at the laboratory scale. Bread pieces with acceptable crumb structure were baked and staling features, according to bread firmness, crumbliness and sensory properties, were measured after storage. Different physical and chemical properties concerning staling were examined, including water-holding capacity, gelatinization, gelation, foaming and particle size of flours, molecule size of water-extracted proteins, and constitution of starch granules. Results showed that the staling rate, bread firmness, crumbliness and sensory properties, of native oat breads deteriorated more rapidly than those of heat-treated and flaked oat breads. The consistency of native oat dough decreased during mixing and the specific volume of native oat breads was the smallest. The moisture content of flaked oat breads was the highest, their firmness and crumbliness increased the least, and their sensory properties remained the best. Flaking increased the water-holding capacity of oat flours and viscosity of the water-extracts, but the good foaming properties of native oats were lost. Heat treatment and flaking increased the peak viscosity of oat flour after gelatinization. Heat treatment and especially flaking of oat improved the baking properties, such as dough handling and specific volume of bread, and reduced the staling rate of oat breads.
  • Kangas, Sauli (Helsingin yliopisto, 2020)
    Modern agriculture is based on intensive farming practices where plant production farms rely on external mineral fertilizers and carbon stocks of the soils are decreasing. At the same time, regional clusters of animal production farms are struggling with excessive manure that increases the risk of nutrient leaching from their fields. To overcome problems related to nutrient loss, eu-trophication of watersheds and greenhouse gas emissions from food production, several national projects aim to promote farmers to use recycled fertilizers. The latter are fertilizers or soil condi-tioners which can be processed from side products such as animal manure, green manure, mu-nicipal biowaste, by-products from food industry or sludges from wood industry. The aim of this study was to determine how different recycled fertilizer products affect grain yield and yield quality of oat as well as how the products perform in relation to nitrogen input. The field experiment was founded in southern Finland where oat was cultivated for three successive years in a five-year rotation. Liquid ammonium sulfate, meat and bone meal pellets and biogas sludge were compared with commercial mineral fertilizer. The control treatments were unfertilized plots and mineral fertilization treatments with three different nitrogen levels between 44–161 kg/ha. There were no statistically significant differences between treatments in terms of grain yield, except for favorable growing season 2017 when unfertilized plots produced the lowest yield. Nor were there differences in protein, starch, fiber or ash content of grains among recycled and min-eral fertilizers over the three years. The grain yield was positively correlated with the amount of soluble and total nitrogen. Having the lowest application level, meat and bone meal produced the highest yield per nitrogen input among fertilizer treatments. The yield results show that ammonium sulfate, meat and bone meal and biogas slurry can be as effective as mineral fertilizers in oat production, if they have the same amount of soluble nitro-gen. Good fertility of the research plot and drought stress during the two following years mitigat-ed differences among treatments so that nitrogen fertilization proved itself useful only in the grow-ing season 2017. To gather enough data and determine the long-term effect of recycled fertiliz-ers, further research should be distributed into several pilot farms. Moreover, the current Finnish fertilizer recommendations should be updated towards experimental nutrient balance models. This could encourage farmers to gather information of the yield-limiting factors and prevent over fertili-zation in poorly responsive soils.
  • Mykrä, Emmi (Helsingfors universitet, 2013)
    Oat (Avena sativa L.) is a crop grown for feed and for food industry. It is the most used fodder plant after barley in Finland and is also exported. In 2011, oat was grown on 308 200 hectares in Finland and the average yield per hectare was 3390 kg. Several fungal and virus diseases cause remarkable crop losses in oats. Especially in the temperate zone, the most common disease is the head blight caused by Fusarium species. These fungi overwinter as mycelium or spores and produce mycotoxins. In Finland, F. culmorum is a common DON toxin producer and F. langsethiae is a T-2/HT-2 toxin producer in oats. Toxins affect the quality of oat yield and can make it unsuitable for use. Therefore, the amounts of mycotoxin allowed in cereals are stipulated by food safety authorities. This thesis was a part of MTT Agrifood Research Finland’s Hyötygeeni project. The aim of the research was to study resistance of eight oat cultivars to F. culmorum and F. langsethiae. Indicators of resistance were germination of the infested seeds, the proportion of infected seeds and the amounts of mycotoxins. The trials were made in greenhouse with artificial inoculations. The results indicated that four cultivars expressed similar levels of resistance to both Fusarium species. Three cultivars had better resistance to F. langsethiae than F. culmorum and only one cultivar had better resistance to F. culmorum than F. langsethiae. In future research, the results can be utilized in resistance breeding. Global warming will increase the risk of plant diseases. On that account importance of breeding will be emphasized.
  • Lehtilä, Lauri (Helsingin yliopisto, 2019)
    Oats is a major crop in Finland, in one of the most remarkable exporter countries of oats. Oat based value-added products have increased their favor both as healthy domestic foodstuff and as valuable export products. Fusarium head blight infections and mycotoxins accumulated to the oat crops because of the head blight infection pose a serious challenge to the oat production. The head blight infections are predicted to become more common in the future due to the climate change, which increases the need for breeding of new resistant cultivars against the head blight infection. Plant breeding needs more effective and reliable methods to face the challenge. Automatic imaging based high-throughput phenotyping methods can be considered as one possibility to intensify plant breeding. Aim of this master`s thesis was to develop methods for phenotyping oats and head blight infected oat spikelets using RGB- and chlorophyll fluorescence imaging sensors of national plant phenotyping infrastructure in Viikki greenhouses of University of Helsinki. Thesis was carried out as a part of FusNaPPI-project of University of Helsinki and Natural Resources Institute Finland (Luke). Resistant oat genotypes against head blight infection were distinguished, growth and morphology of the oats and progression of the head blight infection were monitored by the developed methods. To reach the goals seven oat genotypes different in head blight resistance were grown and imaged using RGB-sensors during their growth and development. Spikelets were collected from the plants in their flowering phase and were put onto the different in vitro –assays. Spikelets were then inoculated putting the inoculum based on conidia of the F. graminearum inside the spikelets and imaged using chlorophyll fluorescence imaging sensors to detect changes in their photosynthesis in different genotypes and in vitro –assays. Different stages of the head blight infection were seen from the fluorescence data. Decreasing of photosynthetic activity of the spikelet tissues was faster in susceptible genotypes than in resistant ones. Oat genotypes that were different in their morphology in different developmental stages were distinguished in the RGB data. In the experiments, progression of the head blight infection was successfully monitored and the known differences in the disease resistance between oat genotypes were confirmed on the basis of the disease propagation speed. Methods of automatic high-throughput phenotyping as a tools for plant breeding were developed and suitability of these methods for plant`s disease resistance screening were successfully tested.
  • Siitonen, Aino (Helsingin yliopisto, 2021)
    Oat has a high content of lipids compared to many other grains. Oat contains lipid hydrolysing enzyme, lipase, and unsaturated fatty acids, which are prone to oxidation. Hydrolytic reactions and oxidation of lipids may cause major quality changes in oats. Oat contains also phenolic antioxidants - tocols, avenanthramides and phenolic acids - that may inhibit lipid oxidation. The aim of this research was to examine how tocols, avenanthramides and phenolic acids act as antioxidants in oat during lipid oxidation. The purpose was to study concentration changes of these compounds in six oat samples in storage. The storage experiment was performed for 12 weeks at 40 °C. Tocols, avenanthramides, phenolic acids and neutral lipids were analysed by liquid chromatography methods after 0, 2, 4, 8 and 12 weeks of storage. Volatile compounds were measured by a solid phase microextraction gas chromatography method. During the storage, volatile compounds, such as hexanal and 2-pentylfuran, were formed especially in groats. Free fatty acids were hydrolysed from triacylglycerols only in groats, because lipase was active in these samples. The α-tocol concentrations of oat samples decreased significantly, 45-77%, in storage. The β-tocotrienol concentrations decreased 34-53%. At the beginning of the storage avenanthramide concentrations showed 20-45% reduction. After that, the concentrations were either stable or increased 10-30%. The phenolic acid concentrations either decreased, increased or were stable during storage. The most significant change was found in unheated groats where the concentration of free caffeic acid increased even 2.6-fold during eight weeks of storage. The loss of α-tocols imply that these compounds are effective antioxidants in oat. This study did not indicate antioxidant activity of avenanthramides and phenolic acids in oat because the changes of these compounds varied in storage. However, the variation of avenanthramide and phenolic acid concentrations may have been caused by their antioxidant activity and release of bound compounds. Thus, further research is needed in order to study the effect of avenanthramides and phenolic acids in oat during lipid oxidation.
  • Väre, Taija (Helsingin yliopisto, 2020)
    Beetaglukaanilla on kyky tuoda viskositeettia ja rakennetta nestemäisiin elintarvikkeisiin. Kyseiset reologiset ominaisuudet ovat tärkeitä elintarviketeollisuudessa, fysikaaliset ominaisuudet ovat syynä beetaglukaanin terveysvaikutuksiin. Beetaglukaanin rakenne ei ole kuitenkaan pysyvä. Rakenteen hajoamista tapahtuu prosessoinnin ja säilytyksen aikana. Elintarvikkeiden muilla makromolekyyleillä ja niiden hapettumisherkkyydellä on merkittävä vaikutus beetaglukaanin pysyvyyteen. Aihetta koskevissa tutkimuksissa on todettu, että hapettuneiden makromolekyylien kuten lipidien lisäksi beetaglukaanin mukana kulkeutuvat yhdisteet, kuten mm. fytaatti, voivat vaikuttaa beetaglukaanin hapettumisstabiilisuuteen ja siten vaikuttaa beetaglukaanin teknologiseen ja fysiologiseen toiminnallisuuteen. Työn tavoitteena oli selvittää kauran ja ohran viljauutteiden koostumus eri makro- ja mikrokomponenttien osalta eli määrittää valittujen yhdisteiden pitoisuus näyteliuoksissa analyyttisin menetelmin. Viljauutteiden sisällön analyysistä toivottiin löydettävän selittäviä syy-seuraussuhteita jo aiemmin osittain vastaavista näyteliuoksista tehdyille löydöksille (viskositeetin menetys), koska beetaglukaanin hajoaminen nestemäisissä matriiseissa voi heikentää elintarvikkeiden laatuominaisuuksia. Tämän tutkimuksen näytteistä kaurauutteiden puskuriuutteissa oli eniten fenolisia yhdisteitä, myös lipidejä määritettiin suurimmat pitoisuudet kaurauutteista. Beetaglukaanipitoisuudet vastasivat aikaisempia määrityksiä vastaavista näytemateriaaleista. Raudan osalta tulokset eivät olleet täysin yhteneväisiä, kun ajatellaan yhteyttä aikaisemmin vastaavista näytemateriaaleista tehtyihin analyyseihin koskien viskositeetin menetystä ja radikaalien muodostumista.
  • Kulin, Elisa (Helsingin yliopisto, 2020)
    In this thesis snack production and oats as a raw material for snacks were reviewed. Oat lipid oxidation and the shelf life of snack products made of oats was also considered. The aim of experimental studies was to find out if it is possible to puff baked snacks in the oven with high temperature without using yeast as a leavener. The test was conducted with two different baking temperatures and with and without added yeast. The shelf life of oat-based snacks with spice extract were also studied for 12 months by sensory evaluation. Lipid oxidation was also measured, and the product quality was determined by microbiological tests. Also, two consumer tests (number of panelists n = 30 and n = 118) were made with the snacks. Statistically there were no difference between two baking temperatures in doughs with yeast, but the higher temperature decreased the average error of snack samples heights. Yeast in the dough was significant. Sensory evaluation panel recognised the hidden, freshly baked reference sample from the actual samples at 6 months’ time. The results from the measurements of lipid oxidation on the effect of spice extract on snacks shelf life wasn’t clear and needs further investigation. The products microbiological quality stayed good the whole time monitored.
  • Alhonoja, Katja (Helsingin yliopisto, 2015)
    Phosphorus (P) plays a major role in cereal production. Total P content is high in Finnish soils but only a fraction of it is available to plants. This phenomena led to generous P fertilization since 1940 increasing the P concentration in fields as well as P balances. Reduced P fertilization since 1970 has decreased soil P concentration, resulting in negative P balances almost in entire Finland. Accumulation of P in the top soil is a result of chemical reactions occurring in the soil. Reactions of P in soils and the ability of the plants to take up P from soil affects the efficiency of P fertilization. P fertilization is most effective when the application rate replaces P removed from the soil in harvested yield. In this theses, results of the long-term fertilization trial (1973-2013) are compiled. The trial included spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and oat (Avena sativa L.). The data gathered was analyzed to investigate crop yield, P concentration of soluble P in soil and the effect of plant species on the concentration of soluble P in soil within 40 years. Rate of P fertilization and plant species affected soluble P concentration in soil. The higher the P fertilization rate was, the higher the soluble P concentration in soil was. The concentration of soluble P did not decrease during the years when the P fertilization rate was reduced. Among all cereals studied, the P balance decreased during the years following the decrease in P fertilization rates. Changes in P balance does not explain chances in soluble P concentration in soil.
  • Hietarinta, Elina (Helsingin yliopisto, 2015)
    Oats is one of the most cultivated grains in the world. Oat contains 5 to 8 % of lipids, which is a lot compared to many other cereals. Most of the oat lipids are triacylglycerols and about 80 % of its fatty acids are nutritionally significant unsaturated fatty acids. Due to high fat content and high amount of unsaturated fatty acids both the processing of oats and the development of new oat products are challenging. Oat lipids and their reactions during the processing and storage are a significant reason for the changes in oat quality and the unpleasant flavour. It is possible to either decrease or increase the stability of lipids with different processing methods. The objective of this study was to examine oat lipid reactions and stability during the storage. Ravintoraisio Oy gave all the samples for the research. There were seven oat products, which all were differently processed. Samples of different ages of these products were analysed. Short-term storage test was made for four samples, over 16 weeks at 40 °C. At first, all the oat samples were milled to small particles and then total lipids of these products were extracted by accelerated-solvent-extraction. Neutral lipid classes, volatile compounds and tocols were measured from the samples. Neutral lipid classes were analysed by the high performance liquid chromatography method with evaporative light scattering detector. Volatile compounds were measured by a solid phase microextraction method with GC-MS. Tocols were measured by the high performance liquid chromatography method with fluorescence detector. All the oat samples contained about 5 % of lipids. Most of the lipids were still triacylglycerols after a long-term storage. Free fatty acids were detected only from non-heat-treated samples. Content of tocols decreased significantly in oat samples during storage. Tocol content decreased when degree of processing rose. The content of oxidation products of oat lipids, like hexanal, also rose during the storage. Hexanal and 2-pentylfuran were the most abundant volatiles in the samples. The highest amount of oxidation products were found in extrudates which were stored for 16 weeks at 40 °C. Based on the results, storing oat products for 16 weeks at 40°C, corresponds with over one year storage at natural storage temperature. The effects of extrusion and heat treatment have strong influence on reactions of oat lipids and storage stability. The lipids of unprocessed oat grains were the most stable. More information is required to identify the exact reason for off-odors and off-flavours.
  • Vikgren, Päivi (Helsingfors universitet, 2017)
    Kauran ja ohran (1→3)(1→4)-β-D-beetaglukaanit muodostavat viskooseja liuoksia ja kykenevät muodostamaan geelejä. Geeliytymisominaisuuksiin vaikuttavat molekyylin rakenne (kuten sellotriosyyli- ja sellotetrasyyli yksiköiden–suhde), koko, beetaglukaanin pitoisuus liuoksessa ja varastointiaika. Kirjallisuuskatsauksessa käytiin läpi beetaglukaanin viskositeetin ja geeliytymisen merkitystä elintarviketeollisuuden tarpeille sekä terveysvaikutuksille. Lisäksi käytiin läpi tekijöitä, jotka vaikuttavat viskositeettiin ja geeliytymiseen. Työn tavoitteena oli selvittää, miten liukenemislämpötila ohjaa ohran ja kauran beetaglukaanin viskositeettia ja geeliytymistä, kun pitoisuus on pieni (ohra 1 % ja kaura 1,5 %). Lisäksi tarkasteltiin, miten liuoksen hapettaminen vaikutti geeliytymiseen. Beetaglukaania liuotettiin 37, 57 ja 85 ºC:een lämpötiloissa ja sen jälkeen puolet näytteistä hapetettiin 70 mM vetyperoksidilla. Näytteiden viskositeettia ja geeliytymistä mitattiin päivinä 1, 4 ja 7 näytteen valmistamisen jälkeen reometrillä ja lisäksi näytteiden sameutta tutkittiin spektrofotometrillä samoina päivinä. Geeliytymislämpötilan optimoimiseksi kauran betaglukaanille tehtiin vielä lisätestejä 35, 37, 40, 45 ja 50 ºC:ssa. Beetaglukaani liukeni 85 ºC:ssa veteen lähes täysin muodostaen jonkin verran viskooseja liuoksia. Hapettuneiden näytteiden viskositeetit laskivat varastoinnin aikana. Nämä liuokset eivät geeliytyneet varastoinnin aikana. Ohran beetaglukaaneista 57 ºC:ssa liuotettu oli viskoosein, ja kauran beetaglukaaneista 37 ºC:ssa liuotettu oli viskoosein. Ohran beetaglukaani kykeni muodostamaan geeliä ainoastaan, kun se oli liuotettu 57 ºC:ssa, kun taas kauran beetaglukaanilla oli laajempi liuotuslämpötila alue. 37 – 50 ºC:ssa liuenneet kauran beetaglukaanit muodostivat geelin. Hapettamattomien näytteiden muodostamat geelit olivat vahvempia kuin hapetettujen. Tulosten perusteella liuotuslämpötilalla oli suuri vaikutus sekä kauran että ohran beetaglukaanin viskositeettiin ja geeliytymiseen. Optimaalinen liuotuslämpötila viskositeetin ja geeliytymisen kannalta ohran beetaglukaanille oli 57 ºC ja kauran beetaglukaanille 37 – 45 º.
  • Niemelä, Sini (Helsingin yliopisto, 2021)
    Kauraa on leivonnan sijaan perinteisesti käytetty puuroissa ja aamiaismuroissa. Syitä tähän ovat muun muassa gluteenin puuttuminen ja korkea beetaglukaanipitoisuus, jotka tekevät kaurasta hyvin haasteellisen leivottavan. Kauramaltaiden käyttöä voitaisiin lisätä kauraleivonnassa, sillä kemialliset muutokset itäneiden jyvien kuivaamisen aikana parantavat kauran suotuisten aistinvaraisten ominaisuuksien voimakkuutta. Eksopolysakkaridien on todettu parantavan vehnätaikinan ja -leivän laatua hidastamalla tärkkelyksen kiteytymistä ja leivän vanhenemista. Eksopolysakkaridin käytöstä kauraleivonnassa ei kuitenkaan ole tutkimustuloksia. Tämän työn kokeellisen osuuden tarkoituksena oli selvittää, parantavatko kauramallasjauho, kauramallasuute ja eksopolysakkaridia sisältävä ruismallausuute kauraleivän laatua. Esikokeissa selvitettiin parantavatko kauramallasuute, eksopolysakkaridia sisältävä ruismallasuute ja kauramallasjauho kaurajauhoseosten vedensidontakykyä (sentrifugointimenetelmä) ja liisteröitymiskäyttäytymistä (RVA ja Mixolab). Taikinoiden konsistenssit tutkittiin aineenkoestuslaitteella (Texture Analyser) käänteisellä ekstruusiolla ja hiilidioksidin muodostus Risografilla. Leivistä tutkittiin ominaistilavuus (VolScan Profiler), vanheneminen (TPA), väri (Minolta CR 400) ja mikrobiologinen säilyvyys. Maltaiden vaikutusta aistittaviin ominaisuuksiin tutkittiin asiantuntijaraadin avulla kuvailevalla menetelmällä. Entsymaattisesti inaktivoidut mallasuutteet paransivat kauraleivontaa ja kauraleipien laatua. Ainoastaan entsyymiaktiivinen kauramallasjauho heikensi kauraleipien rakennetta. Sen sijaan mallasuutteet paransivat rakennetta, väriä ja aistittavia ominaisuuksia. Lisäksi mallasuutteet paransivat taikinoiden hiilidioksidituotantoa ja sitä kautta kauraleipien tilavuutta.
  • Sneck, Anna-Maria (Helsingin yliopisto, 2020)
    The aims of the thesis included firstly to develop a process to prepare an oat-based milk substitute (OBMS) model in laboratory conditions representing industrial scale processing. After that, the quality of the oat-based milk substitutes prepared using the developed model was assessed and related with differences in the compositions of oats. The hypothesis was that the oat samples differ in terms of their behaviour during milk substitute manufacturing as well as final quality characteristics of the milk substitute. The OBMS process included mixing of oat flour with water, homogenisation and enzymatic hydrolysis of starch with α-amylase followed by enzyme inactivation, salt addition, pH-adjustment and removal of insoluble particles. Calcium phosphate and oil were added to the liquid milk phase after which a second homogenisation step and a final heat treatment were performed. The final OBMS was characterised in terms of mass yield, protein and dry matter contents, reducing sugars, particle size, viscosity, colloidal stability and colour. A functional OBMS process was developed and predictably, the oat samples behaved differently in the OBMS process. Mass yield of the OBMS increased as the starch content of the oat groat increased. High ash content of the oat groat correlated well a high protein content in the final OBMS. Viscosity and redness of the final product predicted well the milk yield and furthermore, it was noted that the higher the viscosity of the OBMS was, the slower it sedimented. This work provides relevant information on the oat composition that is suitable for oat-based milk substitutes.
  • Koivisto, Aino (Helsingfors universitet, 2016)
    Fusarium species lower the germination of oat (Avena sativa) seeds and cause losses in yields. Fungicidal seed treatments prevent fungal diseases from spreading through seeds and soil. This study was conducted to determine how different fungicidal seed treatments affect the germination of oat seeds and the Fusarium species present in laboratory conditions applying official ISTA germination test methods on filter paper and sand. Aim was also to detect the damages fungi cause to oat seedlings as well as the effectiveness of different seed treatments and the resistance of oat cultivars to Fusarium. The germination percentages and damages were detected in two studies. In the first study, oat seeds were germinated on both filter paper and sand and treated with fungicidal seed treatments (Baytan Universal, Celest Trio and Zardex G). In the second study, oat seeds were inoculated with Fusarium culmorum and germinated on filter paper. Additionally, the effect of mould fungi on germination in several different geographical areas, years and cultivars was investigated based on the official germination tests conducted by Evira, who used samples analysed for certifying. Differences were detected between cultivars in their germination and damages caused by fungi in different geographical areas and years. In general, there were more damages in the seed lots with lower germination. The fungicidal seed treatments decreased damages clearly but increased germination only slightly. Only slight differences were observed between the researched seed treatments in their abilities to increase the germination of oat but there were greater differences in their abilities to decrease the amount of Fusarium and the damages they caused to oat seeds. The seed treatment with fludioxonil, difenoconazole and tebuconazole as active ingredients was the most effective against the damages caused by Fusarium in laboratory conditions. Additionally, the germination of oat was better with the sand germination method than on filter paper. However, there were more damages on oat seedlings germinated on sand than on filter paper.