Browsing by master's degree program "Elintarviketieteiden maisteriohjelma"
Now showing items 61-80 of 162
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(2022)Demand for plant-based food is growing and alternative protein sources are explored to replace dairy and meat products. Due to weak functional properties of plant proteins compared to milk protein, it is challenging to create the desirable food structure. The coagulation of milk proteins plays an essential role in structure formation of many fermented milk products, but plant pro-teins may not behave in the same way. It is important to study the use of plant proteins in vari-ous food applications to bring organoleptically and nutritionally better plant-based products to the market. The aim of the work was to study transglutaminase (TG) induced gelling of plant-based proteins and determine whether calcium, pH, or enzyme dosage affects the quality of the gel structure. Pea protein isolate and oat protein concentrate were selected as the main raw materials for the study. Three different levels of calcium, pH and enzyme dosages and their effects on protein content (%), firmness (g) and dry matter content (%) of the samples was measured. Experi-mental plan and predictive models of the results was performed with Minitab software. Protein content of the samples was measured by using nitrogen analyzer, firmness of the samples by us-ing TAXT texture analyzer and dry matter content of the samples with moisture analyzer. Tricalcium phosphate was found to weaken the firmness of the samples when the dosage was 0,3 % or more. The most solid gel sample was found in pH 5,1, with small amount of enzyme and 0,05-0,3 % level of tricalcium phosphate. Dry matter of the samples was noted to increase at low pH level. TG increased the dry matter, especially when tricalcium phosphate was not ap-plied. TG was found to be an effective tool to improve protein gelling by forming a solid struc-ture for the samples. Higher amount of TG increased the protein content. It was shown to be possible to modify food characteristics by the studied process parameters, but the data set used in this study was small to provide reliable models. Further research should be done on the ef-fects and relationships between these factors to confirm results of the study.
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(2022)Kaurajuoman tuotannossa syntyvä kiinteä, kaura-aineksesta ja vedestä koostuva sivuvirta ohjataan teollisuudessa lähinnä energiantuotantoon tai eläinten rehuksi. Tällä sivutuotteella voisi ravintoainepitoisena raaka-aineena olla myös muita hyödyntämismahdollisuuksia esimerkiksi elintarvikekäytössä. Kaurajuoman sivuvirrasta ei ole saatavilla juurikaan aiempaa tutkimustietoa, joten hyödyntämisen tueksi tarvitaan lisää tietoa sen koostumuksesta ja ominaisuuksista. Tämän tutkimuksen tavoitteena oli selvittää kaurajuoman sivuvirran kemiallista ja mikrobiologista laatua ja niiden vaihtelua. Kahden eri kaurajuomatuotteen tuotannossa syntyvien sivuvirtaerien koostumusta analysoitiin. Lisäksi tutkittiin sivuvirtanäytteiden säilyvyyttä kahden vuorokauden ajan. Kaurajuoman sivuvirran kemiallinen koostumus vaihteli melko vähän. Sivuvirran proteiinipitoisuus oli korkea, keskimäärin 52,9 % kuivapainosta. Näytteiden keskimääräinen kuiva-ainepitoisuus oli 32,2 % ja pH 6,44. Gluteenipitoisuudessa oli kahden tuotteen välillä selkeä ero: toisen tuotteen sivuvirran gluteenipitoisuus oli keskimäärin 12,9 mg/kg, kun toisen taas 95,2 mg/kg. Tuotteiden välinen ero johtui siitä, että ne oli valmistettu eri kaurajauhoista. Muut erot kemiallisessa koostumuksessa olivat pieniä sekä tuotteiden välillä että eräkohtaisesti. Mikrobiologinen koostumus sen sijaan vaihteli huomattavasti tuotantoerien välillä. Kahden eri tuotteen välillä mikrobiologisessa laadussa ei kuitenkaan ollut merkitsevää eroa. Säilyvyyskokeen tulokset osoittivat, että kaurajuoman sivuvirta on altis pilaantumaan nopeasti tuotannon jälkeen. Pilaantumisnopeuteen vaikuttivat säilytyslämpötila ja erityisesti mikrobiologisen kontaminaation lähtötilanne. Puhtaimmissakin näytteissä bakteerien pesäkemäärä kuitenkin nousi tasolle 10^8 pmy/g kahden vuorokauden kuluessa. Tutkimuksen perusteella kaurajuoman sivuvirta on melko tasalaatuinen ja proteiinipitoisuudessaan arvokas sivuvirta. Raaka aineen korkea pilaantumisriski on kuitenkin otettava huomioon sen hyödyntämistä suunniteltaessa.
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(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.
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(2021)Traditionally, oat has been a significant animal feed source, but during the past a few years the food consumption of oats has increased. It is important to know the baking quality of different oat cultivars and the factors affecting the quality to obtain the best possible quality oats as a raw material. The aim of this study is to define factors that explain the differences in baking quality between oat cultivars and especially study the role of starch. Samples were flour, flakes and dehulled grains from three oat cultivars. The protein and beta glucan content, water binding capacity and particle size distribution of flours were measured. The water binding capacity and hectoliter weight of flakes and hardness of the groats were measured. The properties of starch were examined by Mixolab-analysis, in which the dough is gelatinized and the mixing resistance is measured during heating-cooling program, and by microscopy of starch granules. In addition, test baking of bread was done using only flour, flour and flakes, and flour and pre-gelatinized flakes. The consistency of the oat dough was measured. The size and form, drying, texture and organoleptic properties of oat breads were examined. There were differences between oat cultivar samples in water binding capacity of flour and flakes. The differences correlated with beta glucan and protein content. The minimal water binding capacity of oat flour led to small consistency. Bread made of soft oat dough spread the most during baking and were softest in texture analysis. No differences in oat starch granule structure were noticed in microscopy. Mixolab results indicated that the pasting properties of one oat cultivar sample differed from the two others. P re-gelatinization of oat flakes increased the dough consistency in baking, resulted in stiffer breads, and reduced baking loss, and eliminated differences in shape, hardness and chewiness between oat cultivar samples.
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(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.
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(2022)Kaurasta saatavat terveyshyödyt perustuvat pitkälti sen sisältämän beetaglukaanin toiminnallisiin ominaisuuksiin. On vielä epäselvää, perustuuko beetaglukaanin kolesterolia laskeva ominaisuus ainoastaan sen muodostamaan viskositeettiin suolistossa vai voisiko myös geeliytyminen olla kyseisen terveyshyödyn taustalla. Aiempien tutkimusten perusteella geeliytymismekanismi perustuu pienillä pitoisuuksilla beetaglukaanin osittaiseen liukenemiseen, jolloin liukenemattomat aggregaatit muodostavat geeliverkoston liitoskohdat. Pienissä pitoisuuksissa beetaglukaanirakenteen pienemmän sellotrioosi- ja sellotetraoosiyksiköiden välisen suhteen (DP3:DP4) ajatellaan olevan edullisempi ominaisuus osittaisen liukenemisen ja siten geeliytymisen kannalta. Tutkielman tavoitteena oli selvittää, eroavatko eri kauralajikkeiden beetaglukaanien rakenteet toisistaan ja vaikuttavatko mahdolliset rakenne-erot beetaglukaanin geeliytymiseen. Lisäksi haluttiin selventää beetaglukaanin geeliytymismekanismia ja siihen vaikuttavia tekijöitä. Tutkimushypoteesina oli, että eri kauralajikkeiden beetaglukaanit eroavat toisistaan rakenteen DP3:DP4:ssa, ja tämä ero vaikuttaa niiden geeliytymiseen. Kauranjyvien kuorimisen, darrauksen, jauhatuksen ja beetaglukaanin eristämisen ja saostamisen jälkeen beetaglukaanien rakennetta tutkittiin määrittämällä DP3:DP4 anioninvaihtokromatografialla ja pulssiamperometrisella detektiolla. Jatkoanalyyseihin valittiin kaksi kauralajiketta sekä kauralesekonsentraatti, joista määritettiin beetaglukaanien moolimassat kokoekskluusiokromatografialla käyttäen refraktometrista detektiota, valonsirontadetektiota ja viskositeettidetektiota, beetaglukaanipitoisuus entsymaattisella määritysmenetelmällä, monosakkaridipitoisuudet kaasukromatografilla ja proteiinipitoisuus Dumas-menetelmällä. Geeliominaisuuksia tutkittiin reometrisilla oskillaatiotesteillä. Kauralajikkeiden beetaglukaanien rakenteiden DP3:DP4:issa havaittiin eroavaisuuksia. Jatkoon valitun pienimmän DP3:DP4:n omaava beetaglukaani geeliytyi heikommin kuin kaksi suuremman DP3:DP4:een omaavaa beetaglukaania, mikä oli oletusten vastainen tulos. On mahdollista, että beetaglukaaniuutteiden sisältämät epäpuhtaudet sekä matala beetaglukaanipitoisuus ovat voineet vaikuttaa geeliytymiseen. Suurempi moolimassa, beetaglukaanipitoisuus sekä pidempi varastointiaika johtivat oletetusti parempaan geeliytymiseen. Päätelmänä oli, että pienissä pitoisuuksissa moolimassalla on suurempi rooli geelivahvuuden kannalta, kun DP3:DP4 on sellaisella alueella, joka mahdollistaa geeliytymisen. Tämän tutkimuksen mukaan geeliytyminen on mahdollista pienessä pitoisuudessa, tietyssä ajassa ja fysiologisessa lämpötilassa, joten geeliytyminen voisi osaltaan olla LDL-kolesterolin laskun taustalla. Kuitenkin tarkempia tutkimuksia geeliytymisen ja LDL-kolesterolin laskun yhteydestä tarvitaan.
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(2022)Plant-based proteins are gaining increasing interest among the scientists and consumers due to accelerating health and environmental awareness. Fermentation is a traditional method for improving the shelf-life, nutritional profile and sensory attributes of food. The aim of the Master’s thesis was to investigate the impact of semi-solid fermentation with Pleurotus ostreatus mycelium on faba bean (Vicia faba) and oat (Avena sativa) protein. 16 amino acids were analyzed by UHPLC-PDA -method, and the nutritional value of protein was estimated by calculating Amino Acid Score (AAS) for essential amino acids. The results indicate that the presence of fungus decreased the total protein content of faba bean from 33 % to 27 % while the protein content of other samples remained stable. Significant changes were observed in the amino acid compositions, but the changes were not consistent. Only the content of alanine and valine increased in all three fermented samples. AAS -method showed an increase in the content of some limiting amino acids. Overall, the fermentation with Pleurotus ostreatus seemed to have a slightly positive or neutral impact on the essential amino acid composition of faba bean and oat protein.
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(2020)Oat (Avena sativa) contains peroxygenase enzyme (POX), which has been suggested to be partly responsible for the formation of the bitter taste in aged oat products. Knowledge concerning heat stability and working range (pH and temperature) of oat POX is currently limited. The aim of the study was to investigate oat ́s POX activity and factors contributing to it. To find out variability of activity, laboratory scale de-hulled, non-heated oat groat samples were analyzed for POX activity. Activities of non-heated groats and oat flour from the milling process with heating were compared to see how well the aforementioned processes inactivated POX enzyme. Inactivation by heat treatment was also carried out in a laboratory scale kilning study. Variables were groat moisture, heating temperature and heating time. Furthermore, effects of pH, temperature and addition of calsium in POX activity were studied. First peroxygenase was extracted from the milled oat. Then the oat extract, substrate (methyloleate) and oxidant (cumene hydroperoxide) were allowed to react in predetermined reaction conditions. Finally, fatty acid methyl ester and its epoxide were analysed by gas chromatography combined with flame ionization detector. All the analyzed oat samples were from OatHow project apart from the commercial reference sample. The non-heat treated oat groats were found to vary in their POX activities. Milling process with heating reduced peroxygenase activity compared to non-heat treated groats but did not exhaust it entirely. According to the study the milling process with heating was not able to inactivate POX activity entirely, but was earlier noted to efficiently inactivate peroxidase and lipase. POX activity was reduced with laboratory scale kilning. According to the study, POX is more heat stable than other lipid degrading enzymes in oat. Further research is required to provide more information on oat POX activity, so more stable and high-quality oat products can be able to be produced in the future.
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(2020)Oat starch differs from other cereal starches in morphology and composition. According to the food industry, the usage of oat in baking is restricted by the rapid staling of oat products, meaning they deteriorate in quality, seen as increased hardness and crumbliness. In baking, starch is only partly gelatinized due to restricted amounts of available water. The gelatinization and aging properties of oat starch in limited water are not yet comprehensively known. The aim of this study was to investigate how the stage of gelatinization and total water content affected the aging of gels prepared from oat flours produced by different treatments. In this study, Mixolab was used to prepare gels from oat flour and water with three different water contents (50, 60 and 70 % water) and in three different stages of gelatinization (under, optimally and over gelatinized). The aging of gels was indicated by the change in their hardness which was measured by a Texture Analyzer 1, 2 and 7 days after preparation. Other analyses from the flour samples included water retention capacity by centrifugation method, particle size distribution by laser diffraction and gelatinization behavior in excess water measured by a viscometer (RVA). Results showed that the further the gelatinization proceeded, the more the samples hardened during storage. The hardness of under gelatinized samples did not increase at all. In optimally gelatinized samples the hardness increased in the samples which had the least water. All the over gelatinized samples hardened during storage. The further the gelatinization process had proceeded, the more there probably was solubilized starch in the sample, causing the gel hardness to increase more. The bigger the water content, the softer was the sample. In the samples with the highest water contents, the hardness did not increase rapidly, probably because the solubilized starch molecules were too far apart to create crystal structures. Only minor increase in hardness was observed in gels made from non-heat treated oat flour. This could be explained by the possible enzyme activity in the flour retarding the aging, since the natural enzymes in oat were not inactivated by heat treatment. The differences between flours were explained by their different particle sizes and starch and beta glucan contents. Beta glucan increased the water retention capacity of flour in room temperature. The highest consistencies during gelatinization and hardest gels during storage were produced by the flour which had the highest starch content. It also had the smallest particle size, thus causing it to have the highest water retention capacity.
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(2020)The chemesthesis perception needs to be researched so that we can better understand how it works in different individuals and affects them. Chemesthesis, smell and taste chemical senses have an important role in individual food choices and health. The primary goal was to study the individual differences in perception of chemesthesis. The data for this study was collected at the University of Turku Functional Food Forum sensory laboratory (ISO 8589). The data includes sensory study results about chemesthetic properties such as astringency, burning and cooling, which are the properties analysed in this study. Study subjects (N=196) evaluated the intensity of these three properties. Every property had five sensory samples presented in different concentrations. Based on the results, the intensity rate was classified into three groups (non-sensitive, semi-sensitive, most sensitive) with Hierarchical clustering. The differences of the formed groups were analysed with the one-way multivariate analysis of variance which gave statistically significant results (F = 10.0; p ≤ 0.001). Mean values of the cluster groups from three different chemesthetic properties were combined into chemesthesis scores. Age didn’t affect the chemesthesis score (F = 0.5; p > 0.05). Female subjects’ chemesthesis scores differ from the male subjects’ scores (F = 5.1; p ≤ 0.01). The correlation between chemesthesis and taste was tested from Puputti et al. (2018) created taste score with data from the same subjects, and chemesthesis score. Chemesthesis score and taste score had a positive correlation (r = +0.561; p ≤ 0.01). The results show that individuals differ in the perception of chemesthesis. The chemesthesis score can classify individuals to different sensitivity groups and chemesthesis appears to correlate with taste. There are many chemesthetic sensations whose properties and mechanisms are unknown. The objectives of the research were achieved. The research is a part of Professor Mari Sandell’s the Academy of Finland funded Food Taste research program and was done during the COVID-19 pandemic.
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(2020)One of the most common packaging materials for food is polymers. The properties offered by plastic packaging are good for food, but there is a general demand to reduce the usage of plastic. The demand for reduction is due to the fact that plastic is often made from fossil raw materials. In the case of foodstuffs, it is not possible to completely remove the plastic packaging material as this would result in faster food spoilage and thus greater food waste. The amount of plastic can be reduced by using it as part of the multilayer material. In multilayer materials, the most common raw material is cardboard, which is generated from renewable raw materials. In addition to plastic packaging made of virgin material, plastic materials made from recycled polymers may also be used in food packaging in future, provided that their safety conditions are met. The aim of the study was to investigate the effect of freezing temperatures and ultraviolet radiation (UV) on the properties and aging of recycled plastic. The research methods were divided into physical, barrier and chemical measurements. Samples were imaged using a scanning electron microscope. The hypothesis in the study was that freezing conditions and UV treatment both age the packaging material. UV radiation is expected to age samples more than freezing conditions. The study will focus on PET (polyethylene terephthalate) and LDPE (low density polyethylene) coated cardboards. The study partially answers to the hypothesis. Frost conditions were had weaker aging effect than UV radiation, as expected. On the other hand, recycled plastics cannot be said to be easier to age than virgin materials. Particularly between the different measurements, the materials did not differ clearly in their aging.
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(2022)Plant-based products with good nutritional and sensory quality are needed to facilitate dietary change towards using less of the unsustainable animal origin foods. Extrusion cooking is a way to produce these products cost effectively. A high quality dry-extruded product has porous structure and suitable hardness. These properties can be affected by adjusting the viscosity of the extruded mass. This master’s thesis discusses the properties of colloidal microcrystalline cellulose (cMCC) that affect the structure of dry-extruded textured protein products made of potato protein and faba bean flour made from germinated beans. The aim was to produce a porous, water binding domestic plant-protein product that can be used as part of healthy diet. The hypothesis was that cMCC increases water absorption capacity and changes the stiffness and expansion of the product by increasing viscosity of the mass. The viscosity of raw materials was first examined from flour mixtures and after this mixture of 70:30 faba bean:potato protein with 0; 1.5 and 3.0 % cMCC was extruded in 24; 27 and 30 % water contents. Moisture content, water absorption capacity, water solubility, sectional expansion index, physical properties of dry and swollen extrudates were examined. Products were photographed both dry and after swelling. The nutritional compositions were calculated based on raw material manufacturers’ information. The swollen products contained 15–22 g protein, 11–17 g carbohydrates and 3,5–47,7 fiber g/100 g moist extrudate (31–42 % dry matter) and could be categorized as source of fiber. cMCC improved flowing capabilities of the flour mixture which was observed as more uniform shape of extrudates. Cleaning the equipment was significantly easier with mixtures containing cMCC. cMCC did not increase water absorption capacity but it did decrease water solubility and increased stiffness. Viscosity measurements revealed that potato proteins did not gel. This information could not be utilized in detail to predict viscosities with extrusion because of different flour ratios.
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(2023)Kertakäyttöisten elintarvikepakkausten kysyntä on kasvanut viimeisten vuosien aikana hektisen elämäntavan, urbanisaation ja kasvaneiden hygieniavaatimusten seurauksena. Perinteisesti tällaiset pakkausratkaisut on valmistettu muovista. Ongelmat muovin kierrättämisessä ovat kuitenkin johtaneet globaaliin muoviongelmaan, jonka keskiössä on liiallinen fossiilisten raaka-aineiden käyttö ja roskaantuminen. Euroopan unioni on pyrkinyt lainsäädännöllä puuttumaan muoviroskaan, sillä se on esimerkiksi kieltänyt tiettyjen kertakäyttömuovituotteiden pääsyn markkinoille ja painottanut siirtymistä kiertotalouteen. Ratkaisuna pakkauksia on alettu valmistamaan ympäristöystävällisemmistä materiaaleista kuten selluloosasta, joka on uusiutuva materiaali, helppo kierrättää ja biohajoava. Tutkimuksen tavoitteena on kehittää kompostoituvia kertakäyttöaterimia, jotka valmistetaan selluloosa-arkeista, trikarboksyylihaposta ja polyolista sekä määrittää tapahtuneiden kemiallisten reaktioiden taso. Aterimien valmistusprosessi on yksinkertainen: selluloosa-arkit upotetaan trikarboksyylihappo-polyoliliuokseen, minkä jälkeen arkit lämpökäsitellään. Lämpökäsittelyn seurauksena muodostuu esterisidosverkostoja, jotka tekevät aterimista kovia, mutta joustavia. Työn tarkoituksena on optimoida trikarboksyylihapon ja polyolin suhteelliset osuudet niin, että esterisidoksista muodostuisi tiivis verkosto, mutta trikarboksyylihappoa ei jäisi reagoimattomana jäljelle. Esterisidosten muodostusta mitattiin FTIR-spektroskopialla. Optimaalinen trikarboksyylihapon ja polyolin suhde oli näytteessä 6. FTIR-spektrissä esterisidoksia kuvastaneen absorptiopiikin aaltoluku oli 1733 cm-1. Kyseisen piikin intensiteetti oli visuaalisesti arvioituna selkeästi suurin. Kaikkien näytteiden aaltoluku asettui hieman odottamattomasti noin 1730 cm-1 läheisyyteen, eikä odotusten vastaisesti sitruunahappoa eniten sisältäneiden näytteiden aaltoluvut juurikaan eronneet muista. Näytteessä 6 kaikki yhdisteet olivat kuitenkin tavoitteiden mukaisesti sitoutuneet toisiinsa, eikä tuotteeseen jäänyt ylimääräistä reagoimatonta trikarboksyylihappoa. Tämä varmistettiin liuotustestillä, jossa ei havaittu yhdisteiden liukenemista tuotteesta nesteeseen. Työn lopputuloksena oli tuote, joka vastaa nykyhetken vaatimuksia olemalla biohajoava ja ympäristöystävällinen.
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(2023)High moisture extrusion is a popular method for producing meat analogues with fibrous/anisotropic structure. Textured vegetable protein can resemble chicken meat in particular. However, the selection of plant protein based products could be expanded with various hybrid products, such as extruded mixture of plant and milk proteins. These hybrid products could enable the consumers to shift to a more plant-based diet. The main objective of this study was to investigate how the proportion of whey protein isolate (WPI), water content of the feed (VP) and temperature of the long cooling die (T) affected the structure and properties of the extrudates made of whey and pea protein isolate (PPI) and oat fiber concentrate (OFC) as well as the extrusion process variables. Another objective was to find out how these effects possibly correlated with the formation of a fibrous structure. Extrudates were prepared with a twin-screw laboratory extruder coupled with a long cooling die, and the mixture of ingredients consisted of WPI-PPI-mix (50% of dry ingredients) and OFC (50% of dry ingredients). For the preparation of extrudates, a split-plot Box-Behnken experimental design was chosen with varying values of independent variables: WPI (50–75–100% of protein ingredients), VP (57.2–59.7–62.2%) ja T (40–60–80 °C). The following analyses of the samples were conducted: texture profile analysis (hardness, springiness, gumminess, chewiness), cutting force and anisotropic index measurement, water absorption capacity (WAC) and color analysis (L*, a*, b*). In addition, the extrudates were photographed in order to determine whether a fibrous structure had formed. In the present study, WPI, VP and T contributed statistically significantly to several response variables and they were all equally important in the formation of PLSR model. The following response variables correlated at least partially with the formation of a fibrous structure: high values of anisotropic index, high values of gumminess and chewiness, and low values of WAC. Fibrous structures were formed with all proportions of WPI, and smaller VP and T values of 20–40 °C seemed to combine samples with a distinct fibrous structure. Based on this study, WPI (with PPI and OFC) seems to be a promising raw material for producing fibrous structures. Because WPI, VP, and T contributed statistically significantly to several response variables, the WPI-PPI-OFC extrudates could be modified into versatile products with different properties only by changing process parameters or proportions of raw materials.
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(2023)Uusien proteiinituotteiden kehittäminen on nostanut märkäekstruusion kiinnostavaksi tutkimuskohteeksi. Märkäekstruusiolla voidaan valmistaa liha-analogeja, joissa on lihaproteiineja muistuttavia kuitumaisia rakenteita. Viime vuosina märkäekstruusiotutkimukset ovat keskittyneet yhdistämään kahta tai useampaa erilaista proteiinia ja muodostamaan niistä hybridiekstrudaatin. Yleisesti käytettyjä raaka-aineita ekstruusiossa ovat eri kasviproteiinit, mutta muistakin proteiineista on muodostettu toimivia hybridiekstrudaatteja, kuten maito- ja lihaproteiineista. Tämän tutkielman tavoitteena oli selvittää erilaisten maito- ja perunaproteiiniseosten ja prosessiolosuhteiden vaikutusta kuitumaisen rakenteen muodostumiseen märkäekstruusiossa. Maito- ja perunaproteiinien märkäekstruusiosta on olemassa vain muutamia tutkimuksia, minkä vuoksi aihe on erittäin ajankohtainen tutkittavaksi. Tutkielman hypoteesina oli, että kaurakuitukonsentraatista ja hera- ja perunaproteiinista onnistutaan muodostamaan kuitumaisia rakenteita märkäekstruusiolla. Ekstruusiossa käytettiin kaksiruuvista ekstruuderia, johon liitettiin pitkä jäähdyttävä suutin. Jauheseoksissa kaurakuitukonsentraatin osuus oli vakio (50 %) ja hera- ja perunaproteiinin osuus vaihtelivat. Tutkielman koeasetelmana oli Split-plot-Box-Behnken-koeasetelma, jossa muuttujina olivat heraproteiini-isolaatin osuus jauheseoksessa (25/37,5/50 %), syötetyn massan vesipitoisuus (57,5/60/62,5 %) ja pitkän jäähdytyssuuttimen lämpötila (40/60/80 ℃). Vastemuuttujina olivat paine suuttimella ja vääntömomentti, ja ekstrudaatin rakenneominaisuudet (kovuus, kumimaisuus, kimmoisuus, pureskeltavuus), poikittainen ja pitkittäinen leikkauslujuus, väriparametrit (L*, a* ja b*) ja vedenabsorptiokyky. Tulosten analysointiin käytettiin ML- ja PLSregressioanalyysejä. Hera- ja perunaproteiinista onnistuttiin muodostamaan hybridiekstrudaatti kaikilla käytetyillä prosessiparametrien arvoilla. Lisäksi osaan näytteistä muodostui kuitumainen rakenne. Matala massan vesipitoisuus nosti ekstrudaatin kovuutta, kumimaisuutta, kimmoisuutta, pureskeltavuutta, vääntömomenttia ja painetta suuttimella. Matala jäähdyttävän suuttimen lämpötila suurensi ekstrudaatin kumimaisuutta, pureskeltavuutta, leikkauslujuuksia, vääntömomenttia ja painetta suuttimella. Ekstrudaatin vedenabsorptiokyky suureni, kun heraproteiinin osuus, massan vesipitoisuuden ja jäähdyttävän suuttimen lämpötila kasvoivat. Matala massan vesipitoisuus ja suuttimen lämpötila kasvattivat pitkittäisiä leikkauslujuuksia. Heraproteiinin osuutta nostamalla pitkittäiset leikkauslujuudet suurenivat. Heraproteiinin lisäys vaalensi ekstrudaatteja aiheuttaen niihin keltaisuutta. Tutkielman tulokset tukevat hypoteesia, jonka mukaan hera- ja perunaproteiinista voidaan muodostaa toimiva hybridiekstrudaatti märkäekstruusiolla. Lisäksi ne ovat potentiaalisia raaka-aineita muodostamaan kuitumaisia rakenteita. Jatkossa tarvittaisiin tutkimusta hybridiekstrudaattien aistinvaraisista ominaisuuksista.
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(2023)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.
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(2022)Packaging is necessary in our society and the amount of packaging waste is expected to grow even more on Earth. Various packaging waste sorting symbols try to influence consumers’ waste sorting behavior positively. The aim of the study was to find out how the interviewees consider packaging waste sorting symbols as a way of communication. Also, the current packaging waste sorting symbols were compared with new Nordic recycling symbols. Consumer research was carried out with theme interviews, with a sample of 10 people from the circle of acquaintances. The research materials were analyzed by thematization. The interviewees felt that the new Nordic recycling symbols were more understandable and visually pleasing than the current packaging waste sorting symbols. Several interviewees understood the new Nordic recycling symbols in contrast to the current packaging waste sorting symbols. However, the Mobius loop symbol was recognized as a sign of recyclability in the following symbols: Green Dot, plastic recycling code (PET) and liquid packaging board. None of the interviewees actively looked at the waste sorting symbols on food packaging, but if they happened to look at them, the symbols could possibly help and promote the sorting of packaging waste. According to the interviewees, paying attention to packaging waste sorting symbols could be influenced by placing symbols on the packaging, with sufficiently large size and color. The packaging waste sorting symbols could be made more understandable by adding a short text to the symbol, by also using the same symbols in other context besides packaging and with educating people about their meaning. The most environmentally aware interviewees did not think that the new sorting symbols would increase their existing waste sorting activity.
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(2020)Quinoa has adapted to living under very varied conditions, and within the species, genetic variation is wide. Therefore, there may be differences in the functional properties of quinoa starches between these different varieties and populations. Furthermore, quinoa starch also differs from conventional cereal starches. Thus, knowing these differences is essential in order to find more suitable applications for quinoa in food product development. Increasing the use of quinoa is supported at least by its adaptation to varying growth conditions and nutritional quality. The aim of this master's thesis was to isolate starch from different quinoa varieties and to study the functional properties of starch and to determine the amylose content with the intention to find out whether there are differences in the properties of starches in quinoa varieties. Five different quinoa varieties had been received for this study: Rosada de Taraca, Real quinoa, Titicaca, Pasankalla and Minttumatilda. A separation process was planned for the starch based on previous studies and the separation process was carried out on a laboratory scale. Starch gelatinization properties were measured by RVA (rapid visco analyzer) and by DSC (differential scanning calorimetry) and retrogradation properties by DSC. Amylose content was determined by Megazyme Amylose/Amylopectin Assay Kit. The yield of the separation process remained low. This may have been influenced by the small size of the quinoa starch granules. Differences in gelatinization properties were observed between quinoa varieties. There were more differences at 50% than at 10% starch contents, which could be influenced by different methods. There were also differences in the thermal properties characterizing the retrogradation between the starches at a concentration of 50%. The amylose contents of quinoa starches were low. This may explain why no retrogradation was observed in starch gels containing 10% starch. The starch of the population cultivated in Finland differed from other quinoa starches both in its gelatinization properties and in the thermal properties describing retrogradation. In conclusion, there were differences in the functional properties between the varieties and the choice of quinoa variety is important for the use of quinoa. Quinoa starch differs in characteristics from conventional cereal starches and has its own uses. Thus, increasing the use of quinoa is also supported by the unique properties of quinoa starch.
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(2021)Tutkimuksen aiheena oli lampaanmaidon koostumuksen kausittainen vaihtelu Suomessa ja vaihtelun vaikutus jatkojalostukseen. Lampaanmaidon tuottajat Suomessa ovat havainneet maidon koostumuksen muuttuvan maidonerityskauden aikana. Lampaanmaidosta ei ole tehty tutkimusta Suomessa, joten alan kasvun kannalta tutkimusta voidaan pitää hyvin tärkeänä. Tavoitteena tutkimuksella oli selvittää lampaanmaidon koostumuksen muuttumista Pekkolan tilalla tuotetun lampaanmaidon osalta ja selvittää kuluttajien mieltymystä lampaanmaidosta valmistetun jäätelön suhteen. Lampaanmaidon koostumus voi vaihdella Suomessa olosuhteiden ja ainutlaatuisen lypsylammaskannan vuoksi paljonkin maailmalla havaittuun lampaanmaidon koostumukseen. Lampaanmaitonäytteet kerättiin maidonerityskauden aikana eli touko-elokuu välisenä aikana ja maitonäytteiden koostumusta analysoitiin Hämeenlinnan ammattikorkeakoulun (HAMK) tiloissa Hämeenlinnassa MilkoScan™ Mars -laitteistolla. Aistinvaraisessa kuluttajatutkimuksessa tutkittiin lampaanmaitojäätelö Bäätelön ja vuohenmaitojäätelön Voihan Vuohi! makua, rakennetta ja tuotteiden kokonaismiellyttävyyttä. Tutkimus toteutettiin Hakolan Marjatilalla Janakkalassa. Lampaanmaidon koostumus vaihteli lypsykauden aikana ja esimerkiksi maidon kuiva-ainepitoisuus kasvoi koko maidonerityskauden ajan. Lampaanmaidossa myös rasvapitoisuus kasvoi tasaisesti maidonerityskauden edetessä. Jäätelön valmistuksen kannalta rasva- ja kokonaiskuiva-ainepitoisuuden kasvaminen ovat toivottavia asioita. Aistinvaraisessa arvioinnissa tuotteiden miellyttävyyden välillä ei ollut tilastollisesti merkittävää eroa. Lampaanmaitojäätelön rakenne arvioitiin miellyttävämmäksi kuin vuohenmaitojäätelön ja Bäätelö minttu oli tutkimukseen osallistuneiden kuluttajien suosikki. Lampaanmaidosta valmistettavaan jäätelöön tulisi lisätä maidonerityskauden alussa sekä rasvaa että kokonaiskuiva-aineen määrää, jotta saataisiin aikaan tasalaatuista tuotetta. Konsentroitu lampaanmaito voisi olla ratkaisu. Tutkimusta lampaanmaidon koostumuksen saralla tarvitaan vielä, jotta muitakin lampaanmaitotuotteita voidaan kehittää ja soveltaa esimerkiksi jäätelön valmistukseen. Maitojauhe ja lampaanmaidosta valmistettu kerma ovat seuraavana listalla.
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(2022)Lähes miljardi ihmistä maapallolla elää kroonisesti aliravittuna, ja samaan aikaan ruokaa päätyy jätteeksi noin kolmasosa tuotetusta määrästä. Tätä hävikkiä on mahdollista vähentää käyttämällä ruokajätteeksi luokitellun ruuan raaka-aineena valmistettaessa uutta ruokaa. Tämän tutkimuksen tavoitteena oli kehittää valituilla maitohappobakteerikannoilla optimoitu leipomosivuvirtojen kierrätysmenetelmä, jonka avulla korvataan apu- ja säilöntäaineita leivontaprosessissa. Työssä ratkottiin prosessin ongelmia nostettaessa tuotantoa pilot-mittakaavasta leipomomittakaavaan. Valitun propionihappobakteerikannan (PAB) tuottamalla propionihapolla voidaan estää mikrobien aiheuttamaa leivän pilaantumista ja näin ollen pidentää sen säilyvyyttä. Toinen valittu bakteerikanta tuotti eksopolysakkarideja (EPS), joilla voidaan mm. nostaa taikinan viskositeettia ja lisätä valmiin leivän tilavuutta sekä pidentää säilyvyyttä. Tutkimus toteutettiin vertailemalla pilot-mittakaavan prosessia leipomomittakaavan prosessiin erikseen molemmilla maitohappobakteereilla fermentoidulla ylijäämäleivällä. Fermentointiprosessi suoritettiin Viikissä elintarvike- ja ravitsemustieteiden osaston prosessilaboratoriossa ja leipomomittakaavan leivonnat Koivulan leipomossa Kouvolassa. Leivistä otettiin näytteitä, jotka analysoitiin instrumentaalisesti ja aistinvaraisesti. PAB-leipäraskin vaikutus leivän säilyvyyden parantumiseen oli selvästi havaittavissa homehtumiskokeissa. Nämä suotuisat vaikutukset pystyttiin säilyttämään siirryttäessä laboratoriosta tuotantoympäristöön. Sen lisäksi PAB-pilot- ja -leipomoleipien happamuusarvot olivat hyvin lähellä toisiaan, mikä tukee mittakaavan muutoksen onnistumista. Siirryttäessä laboratoriosta tuotantoympäristöön EPS-leivillä ei tuntunut olevan eroa leivän ominaisuuksissa lukuun ottamatta leipomossa tehdyn EPS-leivän pienempää tilavuutta ja suurempaa kovuutta. Testattu takaisinfermentointi ei onnistunut leipomo-olosuhteissa, mutta sen jatkokehittämiseen saatiin arvokasta tietoa.
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