Browsing by Subject "proteiini"

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  • Peltola, Taru; Kaljonen, Minna; Kettunen, Marita (Taylor & Francis, 2020)
    Sustainability Science Practice Policy 16 1 (2020)
    Reducing meat consumption has become a key concern in attempts to respond to climate change. We explore possibilities to empower collectives of people to reflect on their eating preferences by organizing protein demonstrations for Finnish students aged 10‒16. We analyze the protein demonstrations as public experiments – specific arenas allowing people to experience alternative foods and deliberate on sustainable eating. Video recordings of the demonstrations revealed two key interactive modes that were crucial in this undertaking. Tasting as an embodied form of interaction allowed the students to share their experiences about the foods while playful interactions created a more inclusive and informed setting for engagement. Unlike conventional public engagement methods, the protein demonstrations enabled participants to share their emotions and feelings and to express their doubts and concerns about the idea of sustainable eating. The project revealed tensions between visceral experiences and socially constructed ideas of eating that might otherwise remain unaddressed. The protein demonstrations were thus a means of systematically producing conditions that enabled the elements influencing dietary transition to be made visible and discussed. Addressing these elements is crucial in achieving long-term and internally motivated changes in unsustainable eating preferences.
  • Rissanen, Janina (Helsingin yliopisto, 2020)
    Securing an adequate protein intake raises questions for the future, and various plant protein products have grown in popularity in recent years. Tofu is one of the most popular vegetable protein products due to its versatility. Also, its different structural types are appealing to consumers. One way to increase the value of other grain legumes closer to soybeans would be to develop a tofu analogue from them. Faba beans are potential for this purpose, as they can be cultivated under the northernmost conditions, they are as rich in protein like soybeans and the proteins within soybean and faba bean are similar in structure. This study complements research related to the gelation of faba bean proteins. The aim was to study how different coagulants, their contents and different faba bean protein contents in the emulsion affect the resulting gel structure. The gels produced by each coagulant were examined separately so that the variables, i.e., coagulant and protein contents, were given three different values. The protein content of the emulsion was either 6, 7 or 8% (w/v), and the contents of coagulants were as follows: transglutaminase (TG) 5, 25 or 50 U/g of protein, gluconodeltalactone (GDL) 0.3, 0.65 or 1%, citric acid 0.14, 0.16 or 0.18% and calcium sulphate (CaSO4 · 2 H2O) 0.5, 1 or 1.5% (w/w). The structures of the gels were compared based on the results of Texture Profile Analysis (TPA) and sensory observations, and in addition, the samples were examined for the interactions formed between the proteins. This was done by dissolving the gels in various solvents. Of the gels studied, the most different structure was produced by transglutaminase, which provided a solid-like gel structure at the highest content combined with the highest protein content in the emulsion. Its TPA value for hardness was the highest. The interactions between proteins also differed most when comparing the results of other gels to transglutaminase gels. A probable explanation for these results was the strong isopeptide bonds formed by TG. GDL, citric acid or calcium sulfate did not produce such a solid gel structure, but the structures of the samples were much softer, part almost liquid. The protein content had a statistically significant effect on the hardness of gels coagulated with TG and calcium sulfate, among others. The coagulant content also affected the results of the TPA measurements, but they had less effect than the protein content.
  • Roiniala, Tia (Helsingin yliopisto, 2018)
    Maisterintutkielman kirjallisuuskatsauksessa perehdyttiin härkäpavun ominaisuuksiin ja proteiinijauheiden valmistusmenetelmiin. Kokeellisen osion tavoitteena oli eristää härkäpapuproteiinia ja vertailla konsentrointimenetelmän vaikutusta sumutuskuivatun härkäpapuproteiini-isolaatin ominaisuuksiin ja proteiinin saantoon. Proteiini eristettiin härkäpapujauhosta veteen uuttamalla. Uuttoliuokset konsentroitiin kahdessa erässä, ultrasuodattamalla ja saostamalla, jonka jälkeen konsentroidut liuokset sumutuskuivattiin. Kuivatuista härkäpapuproteiinijauheista tutkittiin vesi- ja proteiinipitoisuudet, partikkelikoko, väri ja funktionaalisista ominaisuuksista proteiinien liukoisuus ja vaahdonmuodostuskyky. Lisäksi laskettiin proteiinisaanto prosessin eri vaiheissa. Ultrasuodatetun härkäpapuproteiinijauheen proteiinipitoisuudeksi saatiin 82 % (märkäpaino), kun taas saostetun proteiinijauheen proteiinipitoisuus oli 94 %. Vesipitoisuudet samassa järjestyksessä 5 % ja 7 %. Ultrasuodattamalla konsentroitu jauhe oli väriltään vaaleampaa ja keltaisempaa kuin saostamalla konsentroitu. Partikkelikooissa ei havaittu tilastollisesti merkitseviä eroja. Proteiinit liukenivat heikosti isoelektrisen pisteen alueella (pH 4–5). Saostettu härkäpapuproteiini-isolaatti liukeni ultrasuodatettua isolaattia paremmin happamassa pH:ssa. Emäksisessä pH:ssa liukoisuus erot tasoittuivat. Ultrasuodatettu härkäpapuproteiini-isolaatti muodosti tehokkaammin ja pysyvämpiä vaahtoja kuin saostettu isolaatti tai härkäpapujauho. Koko prosessin proteiinisaanto jäi matalaksi. Ultrasuodatetulla erällä alkuperäisestä proteiinista saatiin talteen 19,8 %, kun saostetulla saanto jäi 6,7 %:iin. Tulosten perusteella proteiinin eristys onnistui hyvin ja saatiin aikaan härkäpapuproteiini-isolaatteja, proteiinipitoisuuksien noustessa yli 80 %:iin. Konsentroinnilla voidaan vaikuttaa isolaatin proteiini- ja vesipitoisuuteen, väriin ja funktionaalisiin ominaisuuksiin. Menetelmän valintaan vaikuttaa proteiini-isolaatin käyttökohde ja sen vaatimat ominaisuudet. Konsentrointi- ja kuivausmenetelmät vaativat kuitenkin edelleen optimointia, jotta proteiinin saantoa saataisiin nostettua.
  • Siljama, Sofia (Helsingin yliopisto, 2020)
    Johdanto: Suomen väestö on yksi Euroopan nopeimmin vanhenevista. Ikääntyessä ravitsemusongelmiksi nousevat usein energian, proteiinin ja muiden ravintoaineiden riittävä saanti. Ikääntyneillä tehtyjen tutkimusten mukaan heidän ravitsemustilaansa voidaan usein parantaa melko yksinkertaisinkin keinoin, mikäli virheravitsemus ei liity vaikeaan sairauteen. Aiemmissa tutkimuksissa proteiinilla täydennetyt välipalat ovat olleet käyttökelpoinen idea ikääntyneiden proteiinin saannin lisäämiseksi. Systemaattinen tieto ikääntyneiden suosimista proteiinipitoisista välipaloista kuitenkin uupuu. Tavoitteet: Pro gradu -tutkimuksen tavoitteena oli tutkia, saadaanko yli 65-vuotiailla proteiinin saantia lisättyä välipalainnovaatioiden avulla. Lisäksi tavoitteena oli tarkastella sitä, voidaanko kasviproteiineja yhdistämällä kehittää ikäihmisille soveltuvia proteiinivälipaloja. Tutkimuksessa haluttiin myös selvittää, minkälaiset proteiinia sisältävät välipalatuotteet koetaan käytettävyydeltään ja hyväksyttävyydeltään sopiviksi ikääntyneiden ruokavaliossa. Aineisto ja menetelmät: Tutkimus oli pilottitutkimus, jonka asetelma oli satunnaistettu, kontrolloitu interventiotutkimus. Interventioasetelmalla tutkittiin tutkimusryhmien proteiinin saannin muutosta kolmen viikon jälkeen sekä tarkasteltiin käytettyjen tutkimusvalmisteiden vaikutuksia ravinnonsaantiin. Tutkimushenkilöt olivat yli 65-vuotiaita pääkaupunkiseudulla asuvia tutkimukseen vapaaehtoisesti ilmoittautuneita henkilöitä. Tilastollisina menetelminä käytettiin Chi Square-testiä, T-testiä, Fisherin eksaktia testiä sekä kovarianssianalyysia. Tulokset: Tutkittavista oli naisia 30 (88 %) ja miehiä 4 (12 %). Ruokapäiväkirjat analysoitiin 33 tutkittavalta. Tutkittavien painoindeksi oli kontrolliryhmässä keskimäärin 27,2 kg/m2 ja interventioryhmässä keskimäärin 25,9 kg/m2. Proteiinin saanti kehonpainoa (kg) kohden kontrolliryhmässä oli aluksi 0,98g/vrk (SD 0,37) ja lopuksi 0,97g/vrk (SD 0,37). Proteiinin saanti kehonpainoa (kg) kohden interventioryhmässä oli aluksi 1,22 g/vrk (SD 0,30) ja lopuksi 1,22g/vrk (SD 0,30). Muutos sekä kontrolli- että interventioryhmässä oli 0,00 (95 % lv molemmissa -0,01 – 0,01). Tilastollista eroa ei ollut ilman vakiointia (p=0,81) eikä vakioinnin kanssa (p=0,57) (vakiointi alkutilanteella). Tutkimuksessa pilotoitiin välipalojen eri tuotemuotoja ja niiden eri makuvariantteja. Tutkimuksen välipaloihin sisällytettiin vain kasvi- ja maitopohjaisia välipaloja (n=15). Välipalojen kehitystyön seurauksena saatiin tutkimukseen mukaan varsin monenlaisia välipaloja, mutta kasvipohjaisten proteiininlähteiden osalta välipalojen kehitystä olisi pitänyt vielä jatkaa. Kaikilla mittareilla parhaimmaksi koettiin piirakat ja munakkaat. Johtopäätökset: Voimavälipalat-tutkimuksen tutkittavien ruoankäyttöä ei voida yleistää koskemaan kaikkia saman ikäryhmän henkilöitä Suomessa. Tutkimus kuvaa tätä tutkimuspopulaatiota ja heidän ruoankäyttöään. Jatkossa vastaavia välipalatutkimuksia kannattaisi suunnata kotihoidon piirissä oleville ikääntyneille. Tutkimuksessa saatiin arvokasta tietoa tulevaisuuden proteiinivälipalojen kehitystä varten.
  • Helminen, Pirjo (Helsingfors universitet, 2014)
    Thesis literature review deals with composition of cow´s milk, yogurt manufacturing, composition and process attributes affecting textural properties of yogurt and measuring textural properties of yogurt. Plain, stirred yogurts (kg) were manufactured at Valio Riihimäki and Oulu Dairies. The aim of the research was to find out attributes that affect yogurt quality. First milk base composition was determined and, yogurt textural properties were determined (viscosity, graininess, syneresis) using different techniques. Finally yogurt statistical relationships or Pearson correlations and statistical significance between yogurt textural properties and milk base composition and manufacturing process were determined. Additional objective was to determine common specification limits to yogurt textural properties. Statistical analysis; pearson correlation coefficients, p-value and specification limits were carried out using MINITAB®16 statistical software. Good yogurt texture is viscous, free from grains and syneresis. This study showed that yogurt textural properties (viscosity, graininess and syneresis) were affected significantly by yogurt manufacturing plant. There were a lot of fluctuations in yogurt textural properties. Consequently yogurt viscosity fluctuated over 50%, graininess approx. 25% and syneresis approx. 30%. According to this study, yogurts standing a long time before packaging, were less viscose or watery compared to those with shorter standing time prior to packaging. Graininess and evaporating process were found to correlate positively. Yogurts were with more grains when manufacturing process`s evaporating temperature and evaporating rate (l/h) were higher. The higher milk base fat and dry matter content (%) were found to correlate lesser whey separation in yogurt. In addition the higher evaporating rate was in the yogurt manufacturing process, the lesser whey separation was observed. Results from this research are useful for developing dairy processes concerning yogurt manufacturing.
  • Veskimäe, Hele-Mai (Helsingin yliopisto, 2017)
    Jogurtin valmistuksessa ultrasuodatus (UF) on mahdollinen vaihtoehto maitojauhe- tai maitoproteiinilisäykselle. Tutkielman kirjallisuusosiossa perehdyttiin maidon ultrasuodatusprosessiin ja jogurtin proteiinipitoisuuden nostamisen eri vaihtoehtoihin. Kokeellisessa tutkimuksessa pyrittiin selvittämään, voidaanko jogurtin proteiinipitoisuutta säädellä hallitusti hyödyntämällä valmistuksessa ultrasuodatettua maitoa. Kiinnostuksen kohteena oli se, että aiheuttaako maitoproteiinijauheen korvaaminen ultrasuodatetulla maidolla muutoksia jogurtin laadussa. Kokeellisen tutkimuksen aikana valmistettiin rasvattoman maidon ultrasuodatuksella saaduista retentaatista ja permeaatista rasvatonta ja 2 % rasvaa sisältäviä sekoitejogurtteja. Jogurtit valmistettiin eri proteiinipitoisuuksilla niin, että ne vastasivat konsentraatiokertoimia 0,9, 1,1, 1,2, 1,4 ja 1,6. Näiden lisäksi valmistettiin vertailutuote, jossa tarvittava maitoproteiinipitoisuus saavutettiin lisäämällä rasvatonta maitoproteiinijauheetta. Jogurttimaidot fermentoitiin kolmen kaupallisen hapatteen, A1, A2 ja A3, avulla. Näytteet valmistettiin kahtena tutkimussarjana. Ensimmäisessä sarjassa jogurtit valmistettiin kolmella eri proteiinipitoisuudella (konsentraatiokertoimilla 1,1, 1,2, 1,4) ja toisessa sarjaan lisättiin 0,9 sekä 1,6 konsentraatiokertoimet. Valmistetuista jogurteista mitattiin synereesi, pH-arvo ja konsistenssi vuorokauden, 1 viikon ja 2 viikon kylmäsäilytyksen (6 °C) aikana. Näytteitä seurattiin myös aistinvaraisesti ja toiseen tutkimusvaiheeseen sisältyi tuotteiden fermentointiaikainen pH-arvon seuranta. Maitoproteiinijauhelisäyksellä valmistettu ja samalla proteiinipitoisuudella ultrasuodatuksen jakeista valmistettu jogurtti eivät eronneet merkittävästi aistinvaraisessa arvostelussa. Jogurttimassojen laktoosipitoisuudessa ennen fermentointia esiintyi eroja niin, että maitojauhelisäyksellä valmistetussa jogurttimaidossa oli enemmän laktoosia kuin jakeista valmistetuissa jogurttimassoissa. Niin rasvattomien kuin 2 % rasvaa sisältävien jogurttinäytteiden kohdalla nopeiten fermentoitui kaikilla kolmella hapatteella maitojauhelisäyksellä valmistettu massa. Korkeammalla proteiinipitoisuudella olevat massat (konsentraatiokertoimilla 1,4 ja 1,6) saavuttivat tavoite pH-arvon 5 ja 5,5 tunnissa. Kylmävarastoinnin aikaisen heran erottumisen mittauksista havaittiin, että niin rasvattoman kuin 2 % rasvaa sisältävän jogurttimassan 4 (konsentraatiokerroin 1,4) heran erottuminen oli pienintä verrattuna muihin massoihin kaikilla kolmella hapatteella valmistetuissa jogurteissa. Sama massa erottui myös jogurttien konsistenssimittauksissa.
  • Nurmilaakso, Niina (Helsingin yliopisto, 2020)
    Kirjallisuustutkimuksessa käsiteltiin kauran makrokomponentteja, niiden rakenteita ja niiden ominaisuuksia viskositeetin muodostamisessa nesteessä. Lisäksi kirjallisuusosiossa perehdyttiin kasviperäisten nestemäisten elintarvikkeiden valmistusprosesseihin, reologiaan ja ilmiöihin, joita tapahtuu nestemäisissä elintarvikkeissa. Kokeellisen osuuden tavoitteena oli selvittää, voidaanko viidestä kaurajauhosta valmistaa 8 % proteiinia ja 0,4 % β-glukaania sisältävä juoma. Kokeen tarkoituksena oli myös selvittää termostabiilin α-amylaasin ja kahden mallasentsyymiuutevalmisteen kykyä nesteyttää eli pienentää kaurajauhonäytteiden viskositeettia. Kaurajauhonäytteiden liisteröitymisen loppuviskositeetit selvitettiin RVA:lla AACC:n (1997) yleisen tärkkelyksen liisteröimismenetelmän 76-21.02 mukaan ilman entsyymilisäystä ja entsyymien kanssa. Kokeen perusteella näytteiksi valikoitui kaurajauhoista kolme yhdistelmää, jotka täyttivät proteiini- ja β-glukaanipitoisuuskriteerit. Jauhoyhdistelmänäytteille tehtiin myös vertailunäytteet, joihin lisättiin termostabiilia α-amylaasia ja näytteiden loppuviskositeetit selvitettiin RVA:lla. Lisäksi näytteiden faasien erottumista varastoinnin aikana seurattiin. Näytteistä valikoitui aistinvaraiseen arviointiin yksi jauhoyhdistelmä. Näyte, joka sisälsi α-amylaasia, valittiin sen alhaisimman loppuviskositeetin takia. Aistinvaraisen arvioinnin näytteet maustettiin mustikan makuiseksi. Vain yksi jauhonäyte nesteytyi proteiinipitoisuuden ollessa 8 %. Se oli nestemäinen myös ilman entsyymiä. Alhaisen viskositeettinsa takia juomaan voitiin lisätä β-glukaanikonsentraattia, jolloin juoman β-glukaanipitoisuudeksi saatiin 0,4 %. Termostabiili α-amylaasi oli huomattavasti tehokkaampi laskemaan liuoksen viskositeettia kuin mallasentsyymiuutevalmisteet. Juoman rakenne pysyi yhtenäisenä tärkkelyksen muodostaman verkkomaisen rakenteen takia, niissä näytteissä, joissa ei ollut käytetty α-amylaasia. Aistinvaraisessa arvioinnissa α-amylaasin käyttö vähensi aistittua eltaantuneisuutta ja jälkimaun voimakkuutta. Viskositeetin vähäisyydellä ja aistitulla pinnoittavuudella oli käänteisesti yhteyttä hiekkaisuudeksi kutsuttuun ominaisuuteen.
  • Peltola, Kimmo (Helsingin yliopisto, 2019)
    Literature review of this thesis deals with properties and applications of hemicelluloses and stabilizers used in milk products. In addition, the literature review discusses interactions between proteins and polysaccharides and how they affect properties of food products. In the experimental section, interactions between birch glucuronoxylan and milk protein were compared to interactions between gum Arabic and milk protein. Experimental research included interaction tests between polysaccharides and milk protein and preparation of yoghurt. The aim of interaction tests was to find sample compositions where interactions were present. Protein-polysaccharide interactions were investigated with methods based on light scattering, fluorescence spectroscopy, zeta-potential, and electric conductivity. Viscosities, whey separation and sensory properties of yogurt samples were also studied. This study showed that birch glucuronoxylan and gum Arabic have different effect on samples containing milk proteins. When concentrations of glucuronoxylan and gum Arabic were equal, structure of sample with glucuronoxylan was more stable than structure of sample with gum Arabic. Fluorescence spectroscopy showed that glucuronoxylan affected the emission intensity more than gum Arabic. This may be due to stronger interactions between glucuronoxylan and milk proteins compared to gum Arabic. Electric conductivity measurements also showed similar results. Viscosities of reference yoghurt sample and yoghurt sample with glucuronoxylan did not differ. Viscosity of yoghurt sample with gum Arabic was lower than viscosities of other two samples. Whey separation took place in all samples. In sensory evaluation of yoghurt samples, the thicknesses of reference sample and sample with glucuronoxylan were evaluated similar. Sample with gum Arabic was evaluated the thinnest. There were not observable differences in taste of yoghurt samples.
  • Mercier, Léon (Helsingin yliopisto, 2018)
    PURPOSE AND GOALS Microalgae are unicellular eukaryotic organisms capable of photosynthesis. They harvest sunlight and efficiently take up carbon dioxide and nutrients such as nitrogen and phosphorus from their environment and use them for their growth. Due to these properties, their rapid growth and ability to survive in a variety of environments, microalgae have potential in biotechnological applications that promote nutrient recovery and recycling, water purification and the carbon neutral production of biochemicals and possibly biofuels. The purpose of this study was to investigate the suitability of a side stream water originating from the production of baker’s yeast (yeastwater) for the cultivation of a species of microalga called Euglena gracilis. The study aimed to determine the capacity of this water to support growth and protein production of E. gracilis as well as the capacity of E. gracilis to remove nutrients from the water. The effect of filtration of the water on these parameters was also studied. Yeastwater contains an organic molecule called betaine in relatively high concentrations. Betaine has previously been shown to boost the production of the important vitamin cobalamin in bacteria. The study aimed to determine the effect of betaine on the growth of E. gracilis and on the production of cobalamin in the algal-bacterial symbiosis. METHODS E. gracilis was cultured in laboratory scale photobioreactors. Its growth, protein production and nutrient uptake capacity was determined. Baker’s yeast production side stream water diluted with MQ-water was used as the growth medium either in filtered or unfiltered form. A control treatment was prepared where no microalgal inoculate was added to the photobioreactor. The same microalga was also grown in a synthetic nutrient medium with and without betaine. The uptake of betaine and biomass concentrations of cobalamin were determined. For the determination of microalgal growth, dry weight determination and flow cytometry analysis were used. Protein production was determined on the basis of total nitrogen concentration in the biomass. Spectrophotometric measuring kits were used for the determination of nutrient concentrations. Liquid chromatography techniques were used for the determination of betaine and cobalamin concentrations. RESULTS Significant microalgal growth was observed in filtered yeastwater, while growth in unfiltered yeastwater was very low. Nitrogen removal was higher in presence of E. gracilis compared to the control treatment. Protein production in yeastwater was comparable to that of microalgae grown in synthetic medium. E. gracilis grew much better in the synthetic media supplemented with betaine than without the addition. Betaine enrichment had no effect on cobalamin production. Cobalamin was produced in unfiltered yeastwater both with and without the presence of E. gracilis. CONCLUSIONS Unfiltered yeastwater does not support growth of E. gracilis possibly due to its high turbidity. Filtered yeastwater, on the other hand can support the production of E. gracilis biomass. E. gracilis can be used to reduce nitrogen concentrations in yeastwater. Yeastwater can support cobalamin production by bacteria, but this phenomenon did not benefit from the presence of the microalga. The effect of betaine on microalgal growth warrants further study to determine whether it is related to the accumulation of intracellular nutrients, storage compounds or to some other phenomenon. Yeastwater is a promising nutrient feedstock for microalgal biomass production. However, the role of filtration and possibility of using other methods for turbidity reduction needs to be further studied.
  • Perkiö, Pasi (Helsingfors universitet, 2013)
    The aim of the literature review was to examine barley’s (Hordeum vulgare) alcohol-soluble proteins – hordeins and their technological attributes. Additionally, applicability of flow field flow fractionation (FFF) separation method as well as spectrophotometric and light scattering methods for protein characterization was under investigation. The objective of the experimental research was to determine a suitable extraction method for hordeins and subsequent analysis of their molecular weight distribution, size and conformation by the use of AF4 (asymmetric flow field flow fractionation) in combination with MALS-, UV- and RI-detectors. 40 % 1 propanol combined with mild sonication treatment proved to be the most efficient method to extract hordeins from barley flour. In order to prevent deterioration of the FFF channels the solvent had to be diluted to 20 %. Same dilution was used to measure hordeins’ extinction coefficient and to calculate ?n/?c theoretically. Berry plot was found to be the most suitable fit for the data analysis. Extracted hordeins were analysed with SDS PAGE. Extracts contained monomeric C, B and ? hordeins and polymeric B, D and ? hordeins. Also, small amounts of albumins, globulins and hydrolysed proteins were present. Extracts’ fractograms had five distinctive peaks. All of the peaks’ mass fractals and polydispersity indices were above 1, which means analysed aggregates were polydisperse and shaped as complex rods. This can be explained by 1 propanol influenced protein aggregation. Some inference in light scattering was identified in the MALS detector signal. This and the use of measured extinction coefficient and calculated index of refraction caused some errors in the data. The low sample yield (19–26 %) can be explained by the hordeins’ adhering to a syringe filter and adsorbing to the surface of AF4’s ultrafiltration membrane. Also, the use of over simplifying mathematical model to calculate the results and yield could cause some errors in the results. This study showed that it is possible to study Mw, size and conformation of polymeric hordeins with AF4 combined with MALS/UV-detectors and that hordeins form big aggregates in 20 % 1 propanol. For MALS proteins should be extracted in a solvent that will not interfere with subsequent analysis and proteins net charge, which creates a challenge to find proper solvent for hordeins. Nevertheless AF4 proved to be useful and delicate tool for characterizing cereal polymeric proteins.
  • Lius, Elina (Helsingin yliopisto, 2019)
    Finding new plant-based protein sources is important from a sustainable development perspective. Ethanol and starch production from barley results in fiber and protein side-stream fractions that are currently utilized for animal feed. Nonetheless, it would be more profitable if the barley protein side-stream was used as a human food ingredient. The main storage proteins in barley are known as hordeins. They are polymeric proteins and have low solubility, due to their inter-chain and inter-molecular disulfide bridges and hydrophobic side-chains. In food technology applications protein solubility is an important property for emulsifying and foaming functionality. Proteins are sensitive to the surrounding environment, especially to pH, which could be used to alter the solubility. In this thesis the literature review examined barley (Hordeum vulgare) proteins, especially the hordeins, functionality and effect on food materials. The review includes previous studies concerning cereal proteins functionality in general and their effect on food materials and a discussion on protein stabilized emulsions. The aim of the study was to determine the protein composition of two barley protein concentrates, OP1 and OP2, and to evaluate protein solubility and emulsifying properties. Furthermore, the aim of the study was to compare the functionality of the concentrates. According to SDS gel electrophoresis the protein concentrates consisted mostly of hordeins, especially C-hordein and some B-hordein. Minor amounts of other proteins where also identified. The protein solubility was determined by Lowry’s method. The proteins were more soluble in sodium phosphate buffer than in deionized water. In sodium phosphate buffer at pH 3,8 the solubility of OP1 proteins was 100 mg/g ± 11 mg/g and in deionized water at pH 3,9 the solubility was 45 mg/g ± 1,1 mg/g. The solubility of the OP2 proteins in sodium phosphate buffer at pH 3,8 was 47 mg/g ± 1,5 mg/g and in deionized water at pH 3,7 the solubility was 45 mg/g ± 1,1 mg/g. In both samples the proteins solubility increased as the pH increased. Most proteins were solubilized at pH 11: the solubility for OP1 and OP2 proteins were 240 mg/g ± 11 mg/g and 140 mg/g ± 12 mg/g respectively, which is problematic regarding food products, but could be used as a treatment to improve solubility. The smallest oil droplets were formed in emulsions were the pH was adjusted to 7 with sodium phosphate buffer. The stability of emulsions was however poor in all samples because of phase separation, which was already significant after one day of storage. The phase separation was considered to be flocculation which finally resulted in creaming or sedimentation. The flocculation may have occurred due to hydrophobic interactions between the proteins on the oil/water interface. However, shaking of the emulsion causes the flocculated oil droplets to separate, forming an even emulsion. No coalescence was observed in all samples, except for OP1-emulsions with 1 % (w/v) dry matter. These results confirm that these protein concentrates can be used in food products, especially in milk type drinks that need to be shaken before usage.
  • Lukkari, Terhi (Helsingin yliopisto, 2018)
    Kirjallisuuskatsauksessa käsiteltiin yleisellä tasolla hyönteisten turvallisuutta elintarvikkeena, kotisirkan ja jauhomadon koostumusta sekä niiden proteiineja ja proteiinien toiminnallisia ominaisuuksia. Lisäksi kirjallisuusosassa käsiteltiin lyhyesti proteiinien ja rasvojen hapettumista tämän tutkimuksen näkökulmasta. Tutkimuksen tavoitteena oli tutkia prosessoinnin vaikutusta jauhomadon ja kotisirkan proteiinien hapettumiskäyttäytymiseen emulsiossa sekä vaikutusta lipidien hapettumiseen. Lisäksi tavoitteena oli optimoida kotisirkan ja jauhomadon proteiinien uuttomenetelmä. Proteiinien uuttoa optimoitiin eri menetelmillä ja parhaaksi uuttomenetelmäksi osoittautui molemmille hyönteisille uutto-olosuhteet, jossa uuttoliuoksen pH oli 10 ja NaCl -pitoisuus 0,1 M. Jauhomadon proteiinien uuttoon tarvittiin lisäksi rasvanpoisto ennen proteiinien uuttoa. Molempien hyönteisten proteiineja käsiteltiin lämmöllä (+60 °C) ja entsyymillä (transglutaminaasi). Lisäksi jauhomadon proteiinit käsiteltiin uuton yhteydessä sulfiitilla (Na2S2O5) ruskistumisen estämiseksi. Näistä kaikista käsitellyistä proteiineista sekä molempien hyönteisten käsittelemättömistä liukoisista proteiineista valmistettiin emulsiot, joiden hapettumista seurattiin mittausajankohtina 0, 1, 3 ja 7. Proteiinien hapettumista tutkittiin seuraamalla tryptofaanin hajoamista sekä karbonyylien ja dityrosiinin muodostumista fluoresenssispektroskopisella menetelmällä. Lipidien hapettumista tutkittiin seuraamalla konjugoitujen dieenien muodostumista spektrofotometrisesti. Emulsioiden ulkonäköä seurattiin hapettumiskokeen aikana ja emulsioiden partikkelikoko tutkittiin mittausajankohtana 0. Kotisirkan entsyymikäsitellyistä proteiineista valmistetussa emulsiossa proteiinien hapettumista oli havaittavissa, mutta lipidien hapettuminen oli vähäistä. Jauhomadon entsyymikäsitellyistä proteiineista ja kotisirkan lämpökäsitellyistä proteiineista valmistetuissa emulsiossa proteiinien ja lipidien hapettuminen oli vähäistä. Jauhomadon lämpökäsitellyistä proteiinista valmistetussa emulsiossa konjugoituja dieenejä muodostui enemmän kuin muihin näytteisiin. Tässä emulsiossa muodostui karbonyylejä, mutta tryptofaanin hajoamista ei ollut havaittavissa. Sulfiittikäsittely vaikutti altistavan jauhomadon proteiinit hapettumiselle emulsiossa.
  • Kolu, Anna-Maija (Helsingfors universitet, 2013)
    Spray drying is one way to dry protein medicines and it has many advantages compared to other drying methods, for example it is a fast process. In spray drying high temperature and mechanical stress can inactivate the protein. Disaccharides are generally used as protective agents of protein in spray drying because they have an ability to protect the structure of the protein during drying and storage. Aim of this research was to study the stability of the protein during spray drying and storage by using β-galactosidace as a model protein. Aim was also to characterize the physical properties of trehalose and melibiose and to study how well they protect the protein. Some of the central matters to be examined were the glass transition temperature, crystallinity, water activity, yield of the spray dried powder and protein activity. Especially studying the properties of melibiose in spray drying was important because it has not been used before. The study also included the optimization of the process parameters to be suitable for the product. Trehalose and melibiose transformed to an amorphous form during spray drying. Both XRPD and DSC showed an amorfous form. Trehalose and melibiose proved to be good protective agents for the protein during spray drying and storatge probably because they remained their amorphous structure. β-galactosidase remained activity very well. Optimizing of the process parameters was successful because protein remained its activity and still the powder was quite dry and yield was good. The changes in the structure of the protein were studied with FT-IR but the amount of the protein was too small. Problems caused by the spray drier may have an effect to the results, but on the other hand the spray dryer was made to work optimally.
  • Nurmi, Emilia (Helsingin yliopisto, 2018)
    The literature review examined structures and functionalities of two major canola proteins, cruciferin and napin. In addition, fundamental functional properties of proteins and the impact of high intensity ultrasound on functionality of other proteins were reviewed. Ultrasound treatment has been successfully used to improve several functional properties of other proteins such as soy, pea and egg white proteins. However, research on high intensity ultrasound treatment for improving canola protein functionality is limited. The aim of the experimental part was to improve solubility, rheological and emulsification properties of canola proteins using high intensity (20 kHz) ultrasound. The effects of ultrasound treatment on protein structures were also examined. Canola samples were first preheated (95 °C, 5 min) and then treated with ultrasound at different power intensity levels (200 and 400 W) and durations (10 and 30 min). Albumin fractions were obtained by water extraction (pH 7.3) and NaCl extraction (1 M, pH 6.3) was used to obtain globulin fractions. The soluble protein concentration was determined using DC Protein Assay (Bio-Rad, USA), free sulfhydryl content was measured according to Ellman’s procedure and electrophoresis (SDS-PAGE) was performed for the determination of protein composition. Emulsifying ability, creaming index, average particle size, viscosity, storage modulus (G’) and loss modulus (G’’) were determined from the heat-induced emulsion gels. Solubility and emulsion stability of ultrasound treated canola samples were improved compared to control samples. In addition, ultrasound treatment reduced the average particle size. However, the electrophoretic profiles of the control and ultrasound treated canola protein samples did not differ significantly. Based on the rheological measurements, all the emulsion gels were shear thinning and indicated elastic properties (G’>G’’). These results suggest that high intensity ultrasound treatment modified the structures of canola proteins enabling increased molecular interaction and enhancing particularly emulsion gel stability.
  • Uotila, Sarri (Helsingfors universitet, 2013)
    Haemoglobin and globin from blood cells and albumin, fibrinogen and immunoglobulins from blood plasma are the most important proteins in slaughter blood. Different fractions of blood have slightly different technological properties. Adding blood proteins can have an effect on the gelling, foaming and emulsifying properties of foodstuffs. Blood protein hydrolysates have antioxidative and antigenotoxic effects that could be utilised as food preservatives or in functional foods to strengthen health. The nutritional value of food can be improved by adding blood proteins. Blood proteins can be utilized by replacing egg, fat and sodium caseinate in foods, to improve structure and shelf life of food. Blood proteins can also be utilised replacing egg white, milk or soy proteins or replacing fat in light products. Ultrafiltration is a common method in the food industry and it is also suitable for processing blood proteins. The aim of the study was to optimize an ultrafiltration method to concentrate porcine slaughter blood for use in the food industry and to determine the technological properties of plasma concentrate and its suitability for use in the food industry. Response surface methodology was used to create a mathematical model to calculate the optimal ultrafiltration parameters for plasma concentrations. Optimal conditions for the ultrafiltration were an Ultracel PLTK 30 membrane, temperature of 40 ºC and pressure of 2 bar. The technological properties of blood proteins were measured at pH 4.5, 5.5, 6.3 and 7.0. Volume and stability were measured from foams prepared by whipping from plasma concentrate diluted to protein concentration of 5.8 %. Foam volume and stability were greatest at pH 5.5 and weakest at pH 7.0. Emulsifying capacity was measured from plasma concentrate diluted to 0.01 % protein concentration. Emulsifying capacity was weakest at pH 5.5 and increased towards high and low pH. Rheological properties of gels made from 10 % plasma concentrate were measured. The gels were weakest near the isoelectric point of plasma proteins at pH 5.5. Plasma concentrate was used to prepare bologna sausage. The structure and sensory properties of the sausages were evaluated. The sausages containing plasma concentrate were evaluated as equal to control sausages in every category.
  • Valkonen, Sami (Helsingfors universitet, 2014)
    Microvesicles (MVs) are lipid bilayered membranous vesicles containing functional lipids, proteins, RNA and DNA that are produced by most cells. The physiological significance of MVs has become evident, and increased MV counts and the contents of MVs are nowadays also associated with different pathophysiological phenomena. The goal of the field is to use MVs as diagnostic and therapeutic tools. To achieve this, the understanding of the mechanisms of the functions of MVs should be understood better and additionally, reliable methods for the quantification and characterization of MVs should be developed and standardized. The aim of the study was to determine differences in platelet-derived MVs produced by different activation mechanisms. The second aim was to set up and optimize a protocol based on the reaction of sulphur, phosphate and vanillin (SPV) for measuring lipid content of MVs. The third aim was to study the effect of thrombin and proteinase inhibitor PPACK to the vesiculation of platelets. Platelets were isolated from the whole blood of healthy volunteers and vesicles were produced by platelet agonists mediating thrombogenic activation (thrombin and collagen, TC), pathophysiological activation (lipopolysaccharide, LPS) and Ca-ionophore (A23187) as positive control for vesiculation. Quantification and size determination of produced MVs was done using Nanoparticle Tracking Analysis (NTA). MVs were characterized by protein content using bicinchonic acid assay (BCA) and by lipid content using SPV-reaction. MVs had great activation-dependent differences in the lipid and the protein content. Activation with Ca-ionophore produced the most MVs, but the lipid and protein content was only a fraction from (patho)physiologically induced MVs. Only TC increased vesiculation. Vesicle subpopulations had significant difference in lipid content. Thrombin and proteinase inhibitor PPACK mediated inhibition of platelet formation in all of the activations, but the effect was not statistically significant. The mechanism of inhibition was likely to be proteinase inhibitor mediated. The isolation of vesicle populations using differential centrifugation proved to isolate studied populations only partially and the quantification method with NTA was susceptible to concentrated samples. SPV protocol reacted with different intensity to different lipids. In the future, quantification and isolation methods for MVs and the subpopulations of MVs should be improved. Additionally, to understand the physiologically relevant mechanisms of platelet-derived vesicle formation, the inhibitor experiments with PPACK should be continued, because the number of replicates was too low to see significant effects due to a large donor-dependent deviation. Since MVs are heterogenous cellular multitools affecting varying (patho)physiological phenomena, optimization and standardization of methods should be continued in order to study MVs properly.
  • Korpi, Terhi (Helsingin yliopisto, 2019)
    The production of potato starch leads to large amount of separate cellular liquid. So far industries haven’t had use for this potato juice, and it has been distributed back to fields. This causes unnec-essary expenses for industries as well as raises the risk of nutrients leaching. These factors have raised the interest in developing processes for further processing of the cellular liquid. The main interest of industries is still potato starch, which is why they are interested in what affects the nitro-gen and protein content of starchy potatoes and what is their relationship to starch content. This study was done in unison with Perunantutkimuslaitos (Petla) during the starch potato variety test in summer of 2016. In this study the effects of four cultivational factors (site, cultivar, nitrogen fertilization level and time of harvest) were examined via the changes in nitrogen and protein levels in tubers. The weather factors were considered from the data collected from the nearest measure-ment location of the Finnish Meteorological Institute. The goal of the study was to find out what are the factors that have the biggest effect on the changes in nitrogen and protein contents of starch potato variants. Cultivars were found to have the biggest effect, but the site as well as sowing time and weather conditions had an effect as well. Correlation between starch and nitrogen content was not observed. In addition, the goal was to determine the ideal combination of cultivational factors for optimal starch, nitrogen and protein yield. Early variants do have more secure production of yield, since late variants are easier affected from different growing conditions. Raising the level of fertilization to 100 kg/ha was the optimum based on the results of this study, but only if time of harvesting was opti-mized as well.