Browsing by Subject "kaura"

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.

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.

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.

Plant-based meat substitutes produced by high-moisture extrusion are a viable option for meeting the increasing demand for protein and reducing meat consumption. Extrudates produced by high-moisture extrusion resemble meat in structure, mouthfeel and appearance. Combining oats (Avena sativa), which contain unsaturated fats and fibers with protein-rich faba beans (Vicia faba) can result in nutritious meat substitutes. The aim of the Master's thesis was to compare the behavior of three different oat products and faba beans under varying process conditions in high-moisture extrusion. The study focused on the effect of the selected raw materials and process parameters on the structure of extrudates and the formation of fibrous structures. The experimental setup investigated the effect of two independent variables water content (50, 52.5 and 55%) and screw speed (400, 600 and 800rpm) on the response variables. Response variables during extrusion included specific mechanical energy, torque, melt temperature and nozzle pressure. Response variables determined from the meat substitutes were hardness, chewiness, gumminess, springiness, perpendicular and longitudinal cutting strength, water content, water and oil absorption capacities and color (L*, a* and b*). All extrudates produced exhibited some fibrous structures. The study found that high specific mechanical energy, torque, nozzle pressure and melt temperature were favorable for fiber formation. High water content lowered these values during extrusion. Higher screw speed was found to improve the formation of fibrous structure in the extrusion of high-fat oat food ingredients. For protein-rich and low-fat oat fiber concentrate, the best fibrous structures were formed at low screw speed. Additionally, the fibrous structure developed optimally for all blends when the water content in extrusion was lowest. The study found that screw speed had a statistically significant effect on extrusion process variables, while the water content had a more significant impact on variables related to the meat substitutes. The study also found that increase in water content decreased the hardness, chewiness, gumminess, and springiness of samples, while screw speed had the opposite effect. Besides extrusion conditions, differences in the composition of the oat products explained the variations in the samples. For instance, high protein content produced in hard, tough and dense samples. According to research results, oats and faba beans are a potential raw materials for environmentally-friendly and health-conscious meat substitutes. However, high fat content created challenges in the production of fibrous meat analogues. With appropriate process conditions, it was also possible to produce fibrous structures for these samples.

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.

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.

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.

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.

Oats and peas have good nutritional composition and they could make up a favourable raw material combination for extruded food products. However, there are only few studies on their suitability for dry extrusion, especially for textured vegetable protein products (TVP). Based on protein content, dry extrudates can be divided into TVP products having fibrous structure (> 30% protein) and snack products having puffed structure (< 30 % protein). Differences in the structures of extrudates are formed as a result of the raw materials and extrusion parameters. The structure is formed in the extruder chamber, where different unit operations (for example mixing, ripening and shaping) cause many physicochemical changes in the raw materials, such as gelation of starch, denaturation and rearrangement of proteins in flow direction. The aim of the study was to find out how different extrusion parameters, oat raw materials and them concentration affect the properties of TVP products. Oat-based TVP products were targeted to have fibrous structure and resistance for soaking. In the first step, four oat raw materials in three different concentrations (25 %, 30 % and 35 %) were extruded with pea protein isolate. Moisture content, expansion, bulk density, water binding capacity, hardness and chewiness were determined from the products and a soup test simulating cooking was performed. The nutritional contents were calculated based on information received from raw material manufacturers. Based on the analysis results, the best of the oat raw materials (oat protein flour) was chosen for the second stage of the experiments. In the second stage, oat protein flour concentrations of 40%, 50% and 60% of the dry matter were tested. The extrudates were subjected to the same analyses as before. The oat raw material and its concentration were found to have statistically significant effects on many product properties, such as expansion and hardness. The best oat raw material was oat protein flour, from which the extruded products formed a fibrous and soaking-resistant structure. Increasing the oat content of the pulp in the case of oat protein flour resulted in a harder product and the expansion and water binding capacity decreased. Increasing the screw rotation speed was found to increase as well as expansion and water binding capacity. Based on the analyses and sensory observations, it was not possible to decide on the best extrudate, because the evaluation was most influenced by the evaluator's preference questions about for example meat structure. Based on this research, by combining oats and peas it is possible to obtain well-structured TVP products with a concentration of up to 60 % oat protein flour. It may be possible to increase the oat content of the extrudates by combining many oats raw materials, but at the same time it is necessary to ensure that the other properties of the extrudates are preserved.

Raskitus on vanha leivän leivontamenetelmä, jossa vesi-jauho-seosta fermentoidaan mik-robien avulla. Sillä on monia hyötyjä, kuten leivän vanhenemisen hidastuminen, kiven-näisaineiden biosaatavuuden parantuminen ja intensiivisempi maku. Raskituksella voi-daan myös parantaa leivän teknologisia ominaisuuksia, kuten vähentää sisuksen kovuutta ja suurentaa ominaistilavuutta. Raskitusta käytetään yleisesti ruisleivän leivonnassa, sillä rukiin α-amylaasin pitoisuus on korkea, ja raskittamisen aiheuttama pH:n lasku estää sen liiallista toimintaa leivonnan aikana. Kauraleivonta taas on kasvattanut suosiotaan vii-meisten vuosien aikana, mutta raskitus ei ole kauraleivonnassa vielä yleistä. Tämän tut-kielman tavoitteena oli tutkia, miten raskitus vaikuttaa ruis- ja kauraleipien teknologisiin ominaisuuksiin. Tutkimus toteutettiin leipomalla ruis- ja kauraleipiä erilaisten raskien avulla ja analysoi-malla niiden teknologisia ominaisuuksia. Ruisraskit valmistettiin kolmella erilaisella mikrobikombinaatiolla: SPC, C1 ja C2. Kauraraskien valmistukseen käytettiin yhtä mik-robikombinaatiota (C1), mutta raskin aktiivisena ainesosana toimi joko kauramaltaat tai idätetyt kauranjyvät. Tutkituista ominaisuuksista tärkeimmiksi lukeutuivat sisuksen ko-vuus ja leivän ominaistilavuus, sillä ne kertovat leivän laadusta. Sisuksen kovuutta tutkit-tiin rakenneprofiilianalyysillä ja ominaistilavuutta VolScan-laitteella. Näiden ominai-suuksien lisäksi selvitettiin myös leivän happamuus, kosteuspitoisuus sekä laskettiin pais-tohäviöt. Rakenneprofiilianalyysillä leivät tutkittiin yhden ja neljän päivän jälkeen lei-vonnasta, jotta voitiin tutkia raskin vaikutuksia leivän vanhenemiseen. Raskituksen huomattiin parantavan leipien teknologisia ominaisuuksia, koska leivän si-suksen kovuus väheni ja ominaistilavuus suureni. Leivän vanheneminen hidastui raskin käytön myötä. Ominaisuuksien parantuminen oli riippuvainen käytetyistä mikrobeista sekä raskin raaka-aineista. Nämä raaka-aineet olivat ruisleipien kohdalla jauhojen tyyppi ja kauraleipien kohdalla maltaat ja idätetyt jyvät. Kauraleivän kohdalla parantavaa vaiku-tusta teknologisiin ominaisuuksiin havaittiin myös prosessin parametrien ja lisätyn veden määrän muuttamisella.