Browsing by study line "ingen studieinriktning"

One of the greatest challenges of our time is securing the global protein supply for the growing population in a sustainable manner. Fermentation with lactic acid bacteria has a long history of successful employment for the production of fermented foods and beverages. During this study, the ability of diverse lactic acid bacteria for fermentation and sensory improvement of leguminous and cereal protein concentrates was investigated.The main aim of this study was to overcome the sensory limitations of these plant protein ingredients by finding suitable candidates for the design of new starter cultures for their fermentation. A collection of 82 lactic acid bacteria was screened for fermentation of leguminous and cereal protein concentrates with different nutrient supplementations. Most strains required additional nutrients to adequately acidify the leguminous protein concentrate during a 24-h fermentation, while the cereal-based substrate appeared to be a more complete growth substrate. Descriptive sensory analysis also revealed differences in the aroma perceived by a panel depending on the matrix, supplementation and fermenting strain employed. Three of the strains that produced the most desirable aromas and acidified sufficiently the test matrixes were further studied. All three strains preferentially fermented glucose to lactic acid rather than any other sugar. The concentration of hexanal, one of the volatile compounds involved in grassy and beany off-flavor formation, reduced during fermentations in favor of 1-hexanol, a compound with a significantly higher odor threshold. However, only two of the cultures were able to prevent the growth of contaminating bacteria during fermentation. The results of this study can provide guidance for selecting potential starter cultures and fermentation substrate composition to improve the aroma of plant protein ingredients. Two of the selected strains especially have shown potential to be used as starter cultures for the leguminous protein concentrate. Further studies are required to optimize the performance of the selected strains in the test matrixes and to quantitatively characterize their effect on the substrates’ volatile profile, taste and antinutritional factor content

Finding and developing new antimicrobial compounds against clinically important antimicrobial drug resistant bacterial pathogens is necessary to counter the threats to global health, food security and development caused by these organisms. One potential source for leads for novel antimicrobial agents are bacteriophages, whose genomes hold vast numbers of genes encoding for proteins that are able to inhibit bacteria in yet uncharacterized ways. Characterization of these proteins and their functions is likely to aid the discovery of new antimicrobial drugs. This study aimed to optimize the heterologous production of three bacteria-inhibiting proteins from bacteriophage φR1-RT for the characterization of the proteins and their interactions with the bacterial host cell. Expression plasmids were successfully constructed for the heterologous production of the proteins in both Lactococcus lactis and Escherichia coli -based expression systems. The L. lactis expression system utilized a tightly regulated nisin-controlled promoter and featured a lactococcal SSusp45 secretion leader to target the produced protein to extracellular secretion. The E. coli expression system used a tightly regulated arabinose-inducible promoter to control the expression of the bacteriotoxic proteins. Despite the successful construction of the expression plasmids, the bacteriophage φR1-RT proteins were not able to be produced in quantities suitable for protein purification in either of the expression systems used in this study. The lack of protein expression is likely due to either codon bias or the harmful effects of the bacteriotoxic proteins that build up inside the bacterial cells. Codon optimized genes or a eukaryotic expression system could be tried to produce enough protein for purification and further characterization.

New alternatives for meat as the main source of protein are needed due to the negative impact of meat production on the environment and its high utilization of land sources. Vegetable proteins offer a more sustainable choice for meat and they can be processed into a structure that resembles meat using extrusion technology. The aim of this study was to produce a minced meat analogue using extrusion technology. The goal was to gain more information on the textural properties, colour and sensorial features of the meat analogue. In the experimental part, extrudates with replicates were produced from plant protein and fibre concentrate. Three differently processed samples were analysed. Texture analyser was used to measure the gumminess, springiness, chewiness, hardness, adhesiveness and shear energy of the samples. In addition, colour and moisture content were measured and a sensory experiment was conducted. According to the results, the content of the plant protein and fibre concentrate affected the textural properties and the colour of the samples. The results also showed that the composition of minced meat analogue had different effect on the textural properties depending how the sample was processed. In the sensory experiment, the reference sample (minced meat) had significantly higher score of pleasantness compared to extrudate containing samples. No significant differences were observed among the extrudate containing samples. This study showed that a product with some similarities to minced meat can be produced using extrusion technology with plant protein and fibre concentrate. For the development of the meat analogue, a more comprehensive sensory analysis would help to gain more information about the development targets of the product.

The popularity of fermented beverages is on the rise due to signature flavours, associated health and nutritional benefits and a 100% natural label. Research in this sector is currently focused on industrial-scale production of traditional homemade fermented beverages such as Kombucha, Kefir and Kvass. To expand consumer choice beyond these traditional beverages and to provide more nutritional and flavor diversity, it is essential to develop novel products by using new microbial communities and new substrates. The industrial scale-up of fermented beverages produced using microbial communities is challenging as the flavour complexity and functionality of the beverage depends on the complex fermentation processes and interactions between the microbiota species. Fermentation systems that can separate the metabolic stages into separate fermentation steps would be needed to simplify and make the complex fermentation more efficient, scalable, and reliable. The aim of the thesis was to develop and compare different fermentation strategies to control the complex fermentation of previously isolated microbes to produce a bio-flavoured, low-alcohol, malt beverage with a signature fruity flavour and aroma. During the study, green-malt microbial species: Lactiplantibacillus plantarum, Saccharomyces cerevisiae and Saprochaete suaveolens were identified as significant contributors to the development of aroma and flavour compounds in the malt fermentates. Using the optimal cell concentration of the selected species, three different fermentation strategies: simultaneous inoculation, sequential inoculation and sequential fermentation were adopted to design five different fermentation systems. Cocktail blends of individual fermentates were also created and tested for flavour and aroma. All potential production methods were compared in contrast for parameters such as ease of operation, time-efficiency, flavour and aroma, and future scalability. The results showed that complex fermentation of the novel and low alcohol malt beverage could be controlled by selecting organoleptically significant microorganisms from the complex community, controlling the time and order of inoculation and using a stagewise or modular fermentation system. Sequential fermentation produced the desired low alcohol level and flavorful, fruity malt beverages. However, this system required centrifugation at each step and thus resulted in limited ease of operation. Sequential inoculation was an optimal and efficient method of controlling the fermentation since it required a single vessel, and the metabolic stages were separated by inoculating microorganisms sequentially with a 24 h time interval between each inoculation. Creating cocktail blends from individual fermentates also produced bioflavoured, fruity, aromatic, low alcohol malt beverages. This method was time-efficient with maximum ease of operation. The resulting beverages from these different fermentation systems were novel and had fruity flavours and aroma from the metabolites synthesized by organisms S. suaveolens, L. plantarum and S. cerevisiae. Thus, bio-flavoured, low-alcohol, malt beverages with signature fruity flavour and aroma were created at VTT. For the first time S. suaveolens was used in combination with L. plantarum and S. cerevisiae for beverage production using novel three-microbe fermentation systems to control complex fermentation.

There is a growing demand for new, environmentally sustainable, clean label food additives driven by consumers’ desire for healthier and sensorially appealing food products. The aim of this thesis is to study a novel, “clean label” food additive called fibrillated microcrystalline cellulose (fMCC) in the formation of emulsions, elucidate its stabilization mechanism, as well as emulsion storage stability at room temperature over time. To this aim, oil-in-water emulsions with fMCC and vegetable oil were formed via mechanical treatment. It was found that the oil droplets anchor on the surface of the fibrils attached to the microcrystalline cellulose. After homogenization fMCC formed large, entangled aggregates that were located in the continuous phase of the emulsion. This increased the viscosity of the emulsion, which contributed to the stability of the system. During storage, further aggregation was observed. High oil content emulsions exhibit some coalescence, while oil droplets in low oil content emulsions remained unchanged. In this thesis, it was shown that fMCC can be used as a suitable and environmentally sustainable ingredient for emulsion formation and stabilization, with the added benefit of increasing the fiber content of many processed foods and thus increasing their nutritional value.

Mycosporines and mycosporine-like amino acids (MAAs) are small-molecules that provide UV protection in a broad range of organisms. Cyanobacteria produce a diverse set of MAA chemical variants, many of which are glycosylated. Even though the biosynthetic pathway for the production of a common cyanobacterial MAA, shinorine, is known, the biosynthetic origins of the glycosylated variants remains unclear. In this work, bioinformatics analyses were performed to catalogue the genetic diversity encoded in the MAA gene clusters in cyanobacterial genomes and identify a set of enzymes that might be involved in MAA biosynthesis. A total of 211 cyanobacterial genomes were found to contain the MAA gene cluster, with six containing glycosyltransferase genes within the gene cluster. Afterwards, 38 strains from the University of Helsinki Culture Collection were tested for the production of MAAs using QTOF-LC/MS analyses. This resulted in the identification of several novel glycosylated MAA chemical variants from Nostoc sp. UHCC 0302, which contained a 7.4 kb MAA biosynthetic gene cluster consisting of 7 genes, including two for glycosyltransferases and one for dioxygenase. Heterologous expression of this gene cluster in Escherichia coli TOP10 resulted in the production of a glycosylated porphyra-334 variant of 509 m/z by the transformant cells, showing that colanic acid biosynthesis glycosyltransferases can catalyse the addition of hexose to MAAs. These results suggested a biosynthetic route for the production of glycosylated MAAs in cyanobacteria and allowed to propose a putative role for dioxygenases in MAA biosynthesis. Further characterization of additional glycosyltransferases is necessary to improve our understanding of glycosylated MAA biosynthesis and functionality, which could be applied to large scale processes and be used in industrial applications.

Gluteeniton kauraleivonta on teknologisesti haastavaa, sillä viskoelastisen gluteeniverkoston puuttuessa kaurataikinoita on hankalaa työstää ja kauraleivät jäävät usein tiiviiksi, kosteiksi ja tahmeiksi. Hyväksyttävän rakenteen aikaansaanti on vaikeaa ja gluteenittomille leiville on tyypillistä, että ne vanhenevat nopeasti. Leivän vanhenemiseen johtavina tekijöinä pidetään tärkkelyksen uudelleenkiteytymistä ja veden liikkumista leivässä säilytyksen aikana. Tutkimuksen tavoitteena oli parantaa gluteenittoman kauraleivän säilyvyyttä käyttämällä taikinassa esiliisteröityä tärkkelystä. Tutkimuksen hypoteesina oli, että velliksi esiliisteröidyn kaurajauhon käytöllä vesi saadaan sidottua tiukemmin tärkkelysgeeliin, jolloin säilytyksen aikana tapahtuva veden liikkuminen leivässä hidastuu. Kun rakennetta pehmentävä vesi puristuu hitaammin ulos tärkkelysgeelistä ja liisteröityneisiin, amorfisiin tärkkelysalueisiin on sitoutunut enemmän vettä, on leivän rakennetta kovettavien tärkkelyskiteiden muodostuminen hitaampaa. Lisäksi tutkimuksessa vertailtiin kauravellin hapatusta mikrobiologisella ja kemiallisella menetelmällä. Mikrobiologisen hapatuksen aikana jauhopartikkelit ehtivät vettyä ja liueta edelleen, ja tällä oletettiin olevan rakennetta pehmentävä vaikutus. Tutkimuksen kokeellisessa osassa kauraleipien rakenteen kovettumista tutkittiin kaksivaiheisella puristustestillä aineenkoestuslaitteella ja tärkkelyksen uudelleenkiteytymistä seurattiin DSC-kalorimetrillä. Taikinoiden ominaisuuksia havainnollistettiin erilaisin geelitestein. Tutkimuksessa havaittiin, että esiliisteröity kauravelli lisäsi kaurataikinan kaasunpidätyskykyä ja kasvatti kauraleivän ominaistilavuutta. Kemiallisesti hapatettua velliä sisältäneessä kauraleivässä rakenteen kovettuminen oli hitainta ja leipä oli tilastollisesti pehmein kuudenteen säilytyspäivään asti. Mikrobiologisesti hapatetun vellin käyttö taas nopeutti kauraleivän rakenteen vanhenemista. Esiliisteröidyn vellin käyttö pehmensi gluteenittoman kauraleivän rakennetta liisteröimällä enemmän tärkkelystä amorfiseen muotoon ja hidastamalla veden liikkumista leivässä säilytyksen aikana. Kauravellin kemiallinen hapatus pehmensi kauraleivän rakennetta edelleen, ja rakenne oli vellitöntä leipää pehmeämpi vielä kuudentena säilytyspäivänä. Tutkimuksessa onnistuttiin pidentämään gluteenittoman kauraleivän pehmeää aikaa käyttämällä taikinassa kemiallisesti hapatettua, esiliisteröityä velliä.

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.

Inflammatory bowel disease (IBD) is a globally increasing chronic disease, for which the pathogenesis still is unclear. The most common subtypes of IBD are Crohn’s disease (CD) and ulcerative colitis (UC). It is widely known that, in addition to the genetics, an altered immune response against the gut microbiome plays an important role in the development of the disease. For the IBD patients, to whom conventional medication is not sufficient, the TNF-α blocker infliximab, is given. However, about one third of the patients receiving infliximab treatment, do not respond to the drug, or lose response over time. Since there to this day are no reliable diagnostic markers available, the finding of such is of great importance. The goal of this study was to investigate possible markers for drug response in the gut mycobiota composition of IBD patients. The gut mycobiota composition of 72 IBD patients receiving infliximab was studied by MiSeq sequencing of fungal DNA from fecal samples, collected during one year. The sequencing data was analyzed using the mare package in R. In addition, anti-Saccharomyces cerevisiae antibody (ASCA) concentrations were measured from baseline serum samples by ELISA. Finally, calprotectin concentrations were measured from baseline and twelve weeks post infliximab serum samples by ELISA to study whether serum samples could be used instead of fecal samples for measuring calprotectin values. Results show an increase of the Candida and Spiromyces genera in the gut mycobiota of non-responding patients at baseline. At all timepoints, the Spiromyces genus was observed at a higher abundance, compared to the group of patients responding well or partially to the medication. Interestingly, the increase of Candida was seen only in Crohn’s disease patients, when looking at the composition at all timepoints. ASCA values did not differ between the response groups. The serum calprotectin values did not correlate with fecal calprotectin, and serum calprotectin can thus not be used as a marker of gut inflammation. In conclusion, the gut mycobiota can offer predictive markers for drug response prediction to infliximab in IBD patients, which can with further studies offer a clinical diagnostic tool for prediction of drug response.

Tässä maisterin tutkielmassa käsitellään hakusanamainontaa digitaalisen markkinoinnin keinona. Tutkielma lähestyy aiheen teoreettista puolta avaamalla monipuolisesti hakusanamainontaan liittyvää tieteellistä kirjallisuutta. Aiheen empiiriseen puoleen tutkielma keskittyy case-tutkimuksen kautta, jonka aineisto saadaan videotuotantoyrityksen verkkoanalytiikan avulla. Tutkielman johtopäätöksissä puntaroidaan hakusanamainonnan hyötyjen ja kustannusten välistä kuilua ja pyritään arvioimaan, onko hakusanamainonta kannattava investointi videotuotantoyrityksen digitaalisen markkinoinnin kentässä. Hakusanamainonta on oleellinen osa digitaalisen markkinoinnin kenttää. Hakusanamainonnan avulla yritykset pyrkivät lisäämään näkyvyyttä mainostamalla hakukoneessa tuotteita ja palveluitaan potentiaalisten asiakkaiden etsimien asioiden aihepiirien ympärillä. Tutkimuksen empiirinen tutkimusaineisto kerätään Google Analytics työkalulla, joka on monipuolinen ja yleinen verkkoanalytiikan seurantaan käytettävä työkalu. Tutkimusaineistossa keskitytään verkkosivuliikenteen määrää sekä luonnetta esittävien mittareiden tarkasteluun. Tutkimustuloksista ilmenee, että hakusanamainonnan käynnistämisen johdosta case-yrityksen verkkosivuliikenne on lisääntynyt huomattavasti, mikä on johtanut myös verkkosivujen kautta saatujen tarjouspyyntöjen kasvamiseen. Tutkimustulosten myötä on havaittavissa, että hakusanamainonta on kannattava investointi videotuotantoyritykselle sekä hakusanamainonnan kokonaisvaltainen rooli on merkittävä digitaalisen markkinoinnin kentässä.