Browsing by master's degree program "Elintarviketieteiden maisteriohjelma"

The beneficial nutritional quality of oats and the recognition as a naturally gluten-free grain has increased its popularity. In the baking of wholemeal oat bread, the absence of gluten complicates the handling of the dough, and the oat cultivars differ in their baking quality a lot. For now, test baking is the only way to optimize whole oat baking. The aim of this study was to define how oat cultivars differ in their baking quality and how to adjust the dough yield for optimal baking result. The hypothesis was that oat varieties grown in different fields bake differently and by optimizing the dough consistency with dough yield, baking result can be improved. The work examined three oat cultivars and a total of five oat flour samples in the baking of palabread i.e. flat, yeast proofed bread. Moisture content, beta-glucan, and protein contents, pasting curves, particle sizes of flour and water binding were determined from the samples according to standard methods. All flour samples were baked first with dough yield of 215. The consistencies of doughs were measured with backward extrusion method by Texture Analyzer device. Based on the oat bread that proved to be the best in test baking, the optimal level of consistency was determined, to which dough yields were adjusted for the following baking tests. Breads baked with dough yields of 215 and breads obtained from optimized consistencies were compared sensorially and bread staling was measured by the hardness of the crumb for three days after baking. Oat cultivars differed in beta-glucan and protein contents. High beta-glucan and protein content of oat flour resulted in higher water-binding capacity and higher dough consistency. The low water-binding capacity of oat flour was associated with greater drying of the breads and faster aging. Moisture was bound better to the bread when the water-binding capacity of the oat was higher. The consistencies of the dough varieties of oat cultivars differed significantly with the same dough result, and the consistencies obtained from different flour samples of the same cultivars also differed from each other. There were no major sensory differences in the oat breads of the study, but breads baked from different oat flours differed in hardness and aging rates, even though the breads were baked with the same dough consistencies. The optimization of the consistency evened out the quality differences between the oat samples and improved the work-ability of the dough. The optimization was found to be successful in modifying handling of the dough and the structure of the baked bread in desired direction.

Mixed culture beer contains additional microbes in addition to brewing yeast, Saccharomyces cerevisiae. Typical microbes found in mixed culture beer are lactic acid bacteria and other yeast species than S. cerevisiae. Mixed culture beers are usually sour so they can be also called sour beers. They also contain a very small number of hops. German Berliner Weisse and Belgian Lambic are traditional mixed culture beers. Craft beer has made mixed culture beers more popular. This has led to development of new kinds of mixed culture beers. The goal of this study is to establish, can alternative souring microbe be used in brewing. This study wanted to establish does the microbe grow in beer, what kind of substances it produces and how does it affect the sensorial qualities of beer. The study was executed by making two identical beers, which the other was inoculated with the souring microbe and yeast and the other with only yeast. CFU/ml of the souring microbe and yeast was determined by plating. In addition, the most vital carbohydrates, organic acids and the ethanol content together with volatile compounds was determined by liquid and gas chromatography respectively. Samples were taken a duration of three months after which there was a sensory evaluation with a trained panel. Based on the results the souring microbe is suitable for brewing. It grew in beer during fermentation and after bottling. Based on the sensory evaluation, beer containing the souring microbe did not differ considerably compared to beer containing only yeast. It was evaluated to be very similar in measured attributes in the sensory evaluation. The biggest difference between specified substances were in organic acids only found in beer containing the souring microbe. Also, beer containing the souring microbe had deviation in maltose and ethanol content possibly because of contamination. Differences between volatile compounds were small in the two beers respectively. More study is needed to optimise the fermentation process and improve the sensorial qualities with more sensorial study.

Kaurasta valmistettujen tuotteiden suosio on kasvanut viime vuosina. Kaurasta voidaan valmistaa jogurtin kaltaista hapatettua välipalaa, mutta sen laatu ei vastaa vielä maitopohjaista jogurttia muun muassa sen ohuuden ja vetisyyden vuoksi. Suutuntuma on merkittävä tekijä elintarvikkeiden hyväksyttävyyden kannalta. Se on monitahoinen aistittava ominaisuus, jonka tutkimiseen tarvitaan ihmisen aisteja ja kykyä yhdistää erilaisia aistiärsykkeitä samanaikaisesti aivoissa. Aistien välistä vuorovaikutusta on tutkittu paljon, mutta hajun vaikutus ruuan koettuun rakenteeseen on vähemmän tunnettu. Muutamat tutkimukset antavat viitteitä, että elintarvikearomeilla, jotka antavat ruualle makua ja hajua, voitaisiin muokata suutuntumaominaisuuksia. Tämän tutkimuksen tavoitteena oli selvittää, voidaanko sitruuna- ja vanilja-aromeilla vaikuttaa hapatetun kauravälipalan aistittaviin ominaisuuksiin – erityisesti suutuntumaan. Tutkimus toteutettiin COVID-19 poikkeusoloissa Viikin aistilaboratoriossa (ISO8589). Tutkimusmenetelmänä käytettiin yleistä kuvailevaa menetelmää koulutetulla raadilla (n =10). Tutkimusmateriaalina oli viisi hapatettua kauravälipalaa: kahdessa eri aromipitoisuudessa sitruuna (0,05 %, 0,025 %) ja vanilja (0,1 %, 0,05 %) sekä maustamaton. Näytteistä arvioitiin kuutta ominaisuutta: hajun voimakkuus, paksuus, tahmeus, ohenevuus, maun viljaisuus ja makeus. Arviointi suoritettiin ilman nenäklipsiä sekä nenäklipsillä. Tällä tavoin voitiin tarkastella, kuinka ortonasaalin hajuaistin pois sulkeminen vaikutti hapatettujen kauravälipalojen arviointiin. Nenäklipsillä ei arvioitu ominaisuuksista hajun voimakkuutta ja maun viljaisuutta. Arvioinneista tehtiin neljä toistoa. Näytteille suoritettiin väri- ja viskositeettimittaus aistinvaraisen tutkimuksen tueksi. Elintarvikearomeilla oli vaikutusta hajun ja maun ominaisuuksiin: aromit voimistivat hajun voimakkuutta ja makeutta sekä vähensivät maun viljaisuutta. Elintarvikearomit eivät vaikuttaneet näytteiden suutuntumaominaisuuksiin eli paksuuteen, tahmaisuuteen tai rakenteen ohenemiseen. Hajun voimakkuudella, maun viljaisuudella ja rakenteen ohenevuudella havaittiin korrelaatiota keskenään. Nenäklipsin käytöllä oli vaikutusta vain makeudessa vanilja-aromillisilla näytteillä. Instrumentaalisten mittausten perusteella aromit eivät vaikuttaneet näytteiden rakenteeseen. Tutkimuksen tulos oli, että sitruuna- tai vanilja-aromilla ei ollut vaikutusta koettuun suutuntumaan kasvipohjaisilla jogurtinkaltaisilla tuotteilla. Suutuntuman muokkaaminen elintarvikearomeilla on haastavaa, minkä vuoksi niiden käyttö tuotekehityksessä suutuntumaominaisuuksien parantajana ei tällä tiedolla ole kannattavaa. Elintarvikearomeilla oli vaikutusta haju- ja makuominaisuuksiin. Näytteiden makeutta aistittiin vaniljaisilla näytteillä myös hajuaistin kautta. Kiinnostava jatkotutkimuksen kohde on, miten koettu suutuntuma muuttuu erilaisilla aromivalinnoilla.

Due to the high protein content in legumes, legume protein concentrates and isolates are becoming popular and are currently used in food as a substitute for animal-based proteins. Unfortunately, the sensory quality of legumes can be compromised by a beany flavour, bitter taste, and an astringent mouthfeel. The objective of this study was to investigate the bitterness of two faba bean concentrates, one that was untreated and another deflavored to reduce the negative sensory attributes. The presence of bitter tasting compounds in the water-soluble extract of the concentrates was determined using chemical and sensory evaluation. The first hypothesis of the study was that the deflavored concentrate, its water-soluble and water-insoluble fraction are less bitter than the untreated concentrate and its fractions. The second hypothesis was that the water-soluble fraction of the concentrates is more bitter, due to bitter water-soluble phytochemicals. The faba bean protein concentrates were extracted in water and the phytochemical profiles of the water-soluble extracts analysed by UHPLC-MS. The phytochemical profiles of the water extracts were compared and the compounds that differed in their intensity identified based on the mass/charge ratios (m/z) of [M-H]- ions and fragment ions. The bitterness and total flavor intensity of the water suspensions of the concentrates, the supernatants and insoluble residues were investigated by sensory evaluation using a trained panel. The study showed that the aqueous suspensions of both supernatants were as bitter as their concentrates, therefore the compounds causing the bitterness were easily soluble in water. The untreated concentrate suspension and its supernatant were more bitter than the deflavored concentrate suspension and supernatant, suggesting that different amounts of specific compounds in the samples may explain the difference in bitterness. In the UPLC-MS analysis, the intensity of the 12 compounds was higher in the aqueous extract of the untreated concentrate compared to the deflavored aqueous extract. For example, hydroxy fatty acids, some of which have been shown to cause bitterness, were present in the water extracts of the untreated concentrate. The bitter compounds in the concentrate had been reduced or their formation prevented by the deflavoring treatment. Differences in the enzymatic activity of lipase and lipoxygenase enzymes was lower in the deflavored than untreated samples suggesting that an enzyme inactivation treatment may have been used in the production of the deflavored concentrate. Nonetheless, despite the treatment, the deflavored concentrate was still bitter which necessitated more research to identify the bitter compounds and also studies on how to effectively reduce the off-flavour in legume-based protein concentrates.

Edible insects, such as house crickets (Acheta domesticus) are environmentally friendly, nutritious and safe alternative to meat, when special details such as allergenic potential and antinutrients are considered. The goal of this Master’s thesis is to study the processing methods and parameters of house cricket in creating flour for food applications that is safe and of optimal quality. The thesis hopes to provide a reference for parameters used in house cricket drying and milling, with the equipment available. Furthermore, the goal is to study the optimal time to get below critical value in water content of 10 % and within critical values in water activity of 0,25-0,45 with an oven and a freeze-dryer. The samples within the critical safety values with minimal drying time are then milled with centrifugal mill with two different sieve-sizes and particle size distribution is measured and compared between oven-drying and freeze-drying, the two sieve-sizes and to reference flours. Particle size range of 45-150 μm was used as a goal. Optimal measured drying time at T=70 °C for oven-drying was 5 hours. For Freeze-drying at Tp=25 °C, Tc=-87 °C, p=1 mbar was 6 hours. Of the optimally dried samples, Oven-dried sample milled with 0,5 mm sieve size had the lowest mean and median particle size followed by Freeze-dried sample milled with 0,5 mm sieve size. The 5-hour Oven-dried sample milled with 0,5 mm sieve size was thus the closest to the optimal product, because it had the smallest particle size from all the samples with minimal drying time. Samples milled with 1 mm sieve size had coarser mean and median particle size similar to that of the reference samples obtained from the industry. Furthermore, it can be concluded that compared to reference flours, finer house cricket flour can be milled with 0,5 mm sieve size. On the other hand, 1 mm sieve size with the particular centrifugal mill used yields a flour with similar coarse particle size than those used in the industry today. However, Oven-dried samples caused smearing during milling and thus the relationship between drying method and smearing should be studied further. All of the milled samples showed narrower particle size distribution compared to the Reference samples, which indicates a more homogenous flour and thus is considered a desirable trait in this study, when the specific food application is not known. Furthermore, all samples including the Reference samples showed negative skeweness in terms of their particle size distribution.

Palkokasvit ovat osoittautuneet yhdeksi vaihtoehdoksi eläinperäisten proteiinien korvaamiseksi. Esimerkiksi härkäpapua ja hernettä voidaan hyödyntää monipuolisesti erilaisten prosessointimenetelmien avulla. Monille palkokasveille on kuitenkin tyypillistä suuri entsyymiaktiivisuus, mikä johtaa usein epämiellyttäviin sivuflavoreihin. Lipidien hapettumisessa muodostuu välituotteena hydroperoksideja, jotka voivat pilkkoutua pienimolekyylisiksi ja haihtuviksi yhdisteiksi esimerkiksi hydroperoksidilyaasin (HPL) ja alkoholidehydrogenaasin (ADH) katalysoimana. Näitä yhdisteitä ovat esimerkiksi aldehydit, ketonit ja alkoholit ja monille niistä on tunnusomaista ”papumainen” ja ”ruohomainen” aromi. Tämän maisterintutkielman tavoitteena oli selvittää härkäpavun ja herneen hydroperoksideja pilkkovien entsyymien (HPL ja ADH) aktiivisuutta sekä tunnistaa reaktioissa muodostuvia haihtuvia yhdisteitä. Tavoitteena oli myös tutkia sitä, millaisia eroja entsyymiaktiivisuuksissa oli härkäpavusta ja herneestä valmistetuissa proteiinikonsentraateissa ja jauhoissa, millaisia haihtuvia yhdisteitä muodostui ja miten pH vaikutti haihtuvien yhdisteiden muodostumiseen. Tutkimuksessa entsyymiaktiivisuuksia analysoitiin spektrofotometrisesti ja haihtuvia yhdisteitä kaasukromatografisesti HS-SPME-GC-MS-menetelmällä, jossa headspace-kiinteämikrofaasiuutto yhdistettiin kaasukromatografisiin- ja massaspektrometrisiin erotus-, havaitsemis- ja tunnistusmenetelmiin. HPL-aktiivisuutta havaittiin lähes jokaisesta näytteestä, ja erityisesti hernenäytteissä tulokset olivat saman suuntaisia aikaisempiin tutkimuksiin. Proteiinikonsentraattinäytteet osoittautuivat haasteellisiksi materiaalin hienojakoisuudesta ja lopulta suuresta partikkelipitoisuudesta johtuen, mikä johti liian suuriin absorbansseihin. Tästä syystä näille näytteille ei saatu määritettyä luotettavia entsyymiaktiivisuuksia. ADH-entsyymin aktiivisuustulokset perustuivat vain havaintoihin absorbanssin muutoksista, ja erityisesti hernenäytteissä aktiivisuutta havaittiin. Palkokasvinäytteistä määritettiin 10 tärkeintä papumaiseen flavoriin viittaavaa haihtuvaa yhdistettä. Merkittävimpiä yhdisteitä olivat heksanaali, 1-heksanoli, 1-okten-3-oli, 2-etyyliheksanoli ja nonanaali. Hernenäytteissä korostuivat alkoholiyhdisteet, kun taas härkäpapunäytteissä oli enemmän aldehydiyhdisteitä. Hernenäytteissä vallitsevin alkoholiyhdiste oli 2-etyyliheksanoli, jonka pitoisuus proteiinikonsentraattinäytteissä oli poikkeuksellisen suuri. Härkäpapunäytteissä merkittävimmät yhdisteet olivat heksanaali ja 1-heksanoli, mutta myös 1-okten-3-olia sekä nonanaalia esiintyi monissa näytteissä. Härkäpapuproteiinikonsentraatissa oli huomattavasti enemmän heksanaalia kuin jauhonäytteissä. Kontu-lajikkeen kokonaisista härkäpavuista havaittiin enemmän ja monipuolisemmin haihtuvia yhdisteitä, jonka lisäksi entsyymiaktiivisuus oli suurempi kuin Louhi-lajikkeen. Suurimmat haihtuvien yhdisteiden pitoisuudet mitattiin neutraalissa pH:ssa, mutta esimerkiksi alkoholiyhdisteitä mitattiin paljon myös pH 8:ssa pois lukien 1-okten-3-oli, jota havaittiin eniten pH 5:ssä. Havainnot olivat linjassa HPL- ja ADH-entsyymien optimi-pH:n kanssa. Mitattujen entsyymiaktiivisuuksien ja muodostuneiden haihtuvien yhdisteiden yhteyttä ei täysin tässä tutkimuksessa pystytty todentamaan. Monissa näytteissä havaittiin kuitenkin hydroperoksideja pilkkovien entsyymien aktiivisuutta ja näitä entsyymejä vastaavia muodostuvia haihtuvia yhdisteitä havaittiin monipuolisesti erityisesti härkäpapunäytteistä. Tulevaisuudessa härkäpavun entsyymiaktiivisuutta tulisi tutkia lisää ja saada selvyys etenkin ADH-aktiivisuuteen.

Sensory evaluation is necessary to understand the specific sensory characteristics of cheese and its influence on eating behavior. This study aimed to create a flavor profile for five cheese samples that were composed of the same ingredients and maturated in temperature-controlled chambers either in silence or in different types of soundscape frequencies for 4 months. Furthermore, the study examined the impact of soundscape ripening conditions on the sensory profile of the cheese samples. The Generic Descriptive Analysis (GDA) sensory profiling method was conducted with trained study participants, (n =10). The experimental phase covered training the panel, creation of lexicon, 4 training, and 3 evaluation sessions. Intensities of sensory properties were evaluated using a line-scale (0 = not at all to 10 = very strong). The quantitative data was collected based on ISO 8589 standard guiding procedure in the sensory laboratory and processed with various statistical methods. Data for each sensory property was analyzed with the one-way ANOVA using IBM SPSS Statistics. Flavor profiles altogether were analyzed with Principal Component Analysis (PCA) using Unscrambler software. The results of this study showed that the sensory profile of the cheese samples was rich in a total of 17 properties that included 6 senses of smell, 5 senses of touch, and 6 senses of taste attributes. The strongest sensory properties were fattiness perceived both via fingers and mouthfeel. The application of soundscape during cheese maturation processes had no significant impact on individual sensory properties. Based on the one-way ANOVA there were no significant differences between the five cheese samples. However, the principal component analysis indicated that cheese samples formed clusters when entire sensory profiles were taken into account. The effect of soundscape during the maturation period of cheese requires further research.

The scientific data has demonstrated that surface-associated proteins have a significant role affecting the adaptation to GIT environment, adherence to the intestinal mucus and other potential health benefits occurring through cross-talk of propionibacteria and the host. The reported achievements on the complementary proteomic approaches optimize the accuracy of surface protein identification and surface proteins related to anti-inflammatory activities and adhesion has been identified from Propionibacterium freudenreichii strains. Thus, the aim of this thesis was to compare the effect of atmospheric conditions on surfaceome expression of the P. freudenreichii type strain DSM 20271. Bacterial cultures cultivated in aerobic and anaerobic atmosphere were harvested at the mid-exponential phase of growth. Samples were subjected to gel-free proteomic analysis, based on direct analysis of peptides acquired by trypsin cell-surface shaving followed by identification of released surface-attached proteins and peptides using LC-MS/MS and label-free quantification. It was demonstrated in this work that different atmospheric conditions highly influenced the protein expression patterns. Overall, the expression of more than a hundred proteins were affected by the change of environmental condition, of which the majority were predicted not to include either classical nor non-classical secretion motifs. It is still unresolved question if these cytoplasmic proteins in the shaved-fraction could be transported to the bacterial surface area by uncharacterized mechanisms to serve a specific moonlighting function. Few of the identified proteins, most of which were up-regulated in aerobic growth condition, were already described in other bacterial species to be involved with general stress response (ClpP, ClpB, and Ctc) and reduction of reactive oxygen species (Tpx, AhpC, and AhpF).

Japanese quince (Chaenomeles japonica) is a fruit crop that can be used for example in the production of jams, marmalades, juices, soft drinks, and alcohol beverages. Pressing juice from Japanese quince fruits produces large amounts of pomace as a side stream. The aim of the study was to examine the chemical composition of Japanese quince cultivars that are being cultivated in Finland. Both fruits and fruit pomaces were analysed. The effect of enzyme-assisted water extraction on dry matter yield from Japanese quince pomace was also investigated. Fruits and pomaces of cultivars Sirius, Venus, and seed offspring of cultivar Cido were used as research material. Determination of chemical composition was conducted with the analyses of dry matter, lipids, dietary fibre, ash, protein, and carbohydrate content. Fatty acids were extracted with accelerated solvent extraction and were analysed with gas chromatography (GC-FID). With pomaces four different extractions were made: one with plain water extraction, one assisted with pectinase enzyme, one assisted with cellulase enzyme, and one assisted with both pectinase and cellulase enzymes. Dry matter yield of extracts was measured, and extracts were also filtered with ultrafiltration (UF). UF permeates were analysed with ELSD-UPLC to detect sugars and organic acids from the extracts. According to this study cultivar had a significant impact (p < 0.05) on dry matter, protein and lipid content and fatty acid composition of fruits. With pomaces there were also significant differences in dietary fibre contents. Most of the dietary fibre was insoluble dietary fibre. The main detected fatty acids were C16:0, C18:1 (n-9) and C18:2 (n-6). Water extraction assisted with both pectinase and cellulase enzymes had significantly higher extraction yield (29.5%) compared to water extraction assisted with cellulase enzyme (24.2%) and plain water extraction (26.4%) which did not differ statistically (p < 0.05). Extraction yield from pectinase assisted extraction (28.4%) differed only with the yield from cellulase assisted extraction (p < 0.05). All the permeates contained mostly malic acid. Fructose, glucose, and little amount of sucrose were also detected. There were only little differences between composition of permeates. Chemical composition of fruits may vary between growing seasons and thus, repeating the analyzes during several harvest seasons would provide more information on what kind of effect growing season has on fruit composition. This study also raised further questions on what kind of impact of pretreatments prior enzyme assisted extraction could have on the extraction yield.

Plant proteins have excellent nutritional quality and their use in food is constantly increasing. Plant protein powders are widely used as raw material for plant protein products. Characterization of the sensory properties of plant protein powders is important for product development. Aim of the study was to study the sensory properties of six different plant protein powders using a descriptive analysis. The aim was to obtain new information about the sensory properties of plant pro-teins. Study was conducted during the COVID-19 pandemic. The intensities of the sensory properties of the plant protein concentrates, i.e., faba bean, brown pea, yellow pea, hemp, flaxseed and pea protein isolate were studied by a generic descriptive analysis. The trained panel created a vocabulary for the sensory properties of plant proteins and sensory profile of 17 properties was formed. The profile included six smell, four texture, two flavor, and five taste-related properties together with suitable reference samples. Assessors evaluated the samples in three separate sessions. The results showed that the brown and yellow peas had very similar profiles. Their typical smell properties were grassy, smell and flavor of fresh pea, sweetness, bitterness and mouth-drying sensation. The bitterness and mouth-drying sensation of the faba bean were strongest of all and it also contained more grain and musty smell compared to the peas. The properties of the pea protein isolate differed from brown and yellow peas because in umami taste and pea-like properties. Oilseeds, i.e., hemp and flaxseed were dominated by a grain and musty smell, as well as rough-ness and sandiness. The smell and flavor properties of the cooked peas were mild in the plant pro-tein samples because the properties of cooked peas are created during the production of plant protein products. Due to the high protein concentration of pea protein isolate it differed most from all the other samples.