Browsing by department "Elintarvike- ja ympäristötieteiden laitos"
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(2017)Aflatoxins are harmful compounds found in food and feed. The literature review of this thesis looked at aflatoxin M1 (AFM1) found in milk and its occurrence, significance and prevention methods using lactic acid bacteria (LAB). Furthermore, the assay methods of aflatoxins and the factors affecting the analysis were discussed. The aim of the experimental work was 1) to investigate the ability of five LAB strains to bind AFM1 in vitro and 2) to investigate how different matrixes affect the assay of AFM1 and to evaluate the feasibility of the selected ELISA kit for the study. In the first phase of the study the AFM1 concentrations of three different matrixes were analyzed using ELISA when known concentrations of the AFM1-standardsolution were added (0, 20 ja 40 ppt). In the second phase of the study the abilities of five LAB strains to bind AFM1 in UHT skimmed milk and MRS-broth were investigated. The bacterial suspensions were incubated at +32 °C for one hour, and the AFM1 concentration in the matrixes were 50, 15 and 10 ppt. The unbound AFM1 concentrations of the supernatants were analyzed from the samples using ELISA. The unbound AFM1 concentrations were converted to the proportional portion of the bound AFM1. In this study, statistically significant differences were observed in the abilities of the LAB to bind AFM1. The viable cells of strain B2 27 (Lb. plantarum-, pentosus- or paraplantarum) were the best binders of AFM1. They removed 43.7 % AFM1 in UHT skimmed milk, where the AFM1 concentration was 15 ppt. Unlike in previous studies viable cells bound AFM1 better than the heat-killed cells. The used ELISA kit was a sensitive method for analyzing low concentrations of AFM1, but at higher concentrations the assay results were inaccurate. The nonspecific interaction due to the components of the matrixes had to be taken into account when the results were reviewed. In the future, it may be possible to utilize the LAB strains, such as B2 27 for reducing AFM1 the concentration in milk and probably in other foodstuffs. There is a need to develop a practical application which can be used in the binding of AFM1 using lactic acid bacteria and thus reduce the bioavailability of AFM1.
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(2016)Johdanto: Ahmintahäiriö on syömishäiriö, jonka oireita ovat toistuvat ahmintakohtaukset. Niiden aikana syödään suuri määrä ruokaa lyhyessä ajassa ja menetetään syömisen hallinta. Tyypillistä on, että ahmija syö pitkin päivää, eikä syömiseen välttämättä liity nälkää. Koska ahminta tuottaa häpeää, ahmija syö yksin. Ahmintaan liittyy itsehalveksunnan ja syyllisyyden tunteita, ja se aiheuttaa voimakasta ahdistuneisuutta. Ahmintahäiriöön ei kuulu tyhjentäytymistä tai muita kompensaatiokeinoja painonnousun estämiseksi kuten bulimia nervosassa. Ahmintahäiriö voi johtaa lihavuuteen, joka on riskitekijä mm. tyypin 2 diabetekselle. Tavoite: Ahmintahäiriön ja ahmintaoireiden esiintyvyydestä suomalaisilla nuorilla naisilla ja miehillä ei ole tietoa. Tämän tutkimuksen tavoitteena oli selvittää, miten yleisiä ahmintahäiriö ja ahmintaoireet ovat tutkittavassa aineistossa oirekyselyn (Eating Disorder Inventory, EDI) ja puolistrukturoidun haastattelun (Semistructured Clinical Interview, SCID) perusteella. Lisäksi selvitettiin masennuksen ja muiden syömishäiriöiden esiintyvyyttä sekä lihavuuden tai ylipainon riskiä ahmintahäiriöisillä naisilla. Samalla selvitettiin diagnostisten tunnuslukujen avulla EDI-oirekyselyn soveltuvuutta ahmintahäiriön tunnistamiseen riskiryhmistä. Aineisto ja menetelmät: Nuorten Kaksosten Terveystutkimuksen (FinnTwin16) osanottajat eli Suomessa vuosina 1975‒ 1975 syntyneet kaksoset (N=5258, 2835 naista, 2423 miestä, vastausprosentti naisilla 87 ja miehillä 83) täyttivät syömishäiriöitä seulovan kyselylomakkeen, joka sisälsi kysymyksiä painosta ja syömiskäyttäytymisestä sekä syömishäiriöiden oireita mittaavan EDI-osion. Seulontapositiiviset naiset, heidän kaksossiskonsa ja satunnaisotos seulontanegatiivisia naisia kutsuttiin puhelinhaastatteluun, jossa diagnosoitiin puolistrukturoidun SCID-haastattelun avulla anoreksia nervosa, bulimia nervosa, ahmintahäiriö ja masennus DSM-IV-tautiluokituskriteereihin perustuen. Miehiä ei haastateltu. Epidemiologisten tunnuslukujen ja logistisen regression avulla kuvattiin ahmintahäiriön ja ahmintaoireiden esiintyvyyttä ja ahmintahäiriön kliinistä kuvaa. Lisäksi EDI-kyselyn soveltuvuutta ahmintahäiriön tunnistamiseen riskiryhmistä selvitettiin herkkyyden ja tarkkuuden receiver operator curve (ROC) -analyysin avulla. Tulokset: Haastattelun perusteella 15 naista sai ahmintahäiriön DSM-IV-diagnoosin (esiintyvyys 0,5 %, ilmaantuvuus 30/100000 henkilövuotta). Muu syömishäiriötausta ahmintahäiriöisillä oli epätavallinen, mutta masennusta esiintyi noin kolmanneksella. Ahmintahäiriöisillä naisilla oli yli 10-kertainen riski (95 %:n luottamusväli 3,0–35,0) ylipainoon tai lihavuuteen (painoindeksi > 25kg/m2) verrattuna kohortin terveisiin. Yksittäisistä ahmintaoireista naisilla yleisimmät olivat tunnen syyllisyyttä ylensyötyäni (20 %), ahdan itseni täyteen ruokaa (13 %) ja syön silloin, kun olen poissa tolaltani (13 %). Miehillä yleisin ahmintaoire oli ahdan itseni täyteen ruokaa (17 %). Paras ahmintahäiriön seula ROC-analyysin perusteella oli EDI:n kolmen ala-asteikon kokonaispistemäärä (AUC-arvo 0,9, herkkyys 86 % ja tarkkuus 82 %). Johtopäätökset: Tulosten perusteella ahmintahäiriö oli harvinainen naiskaksosilla, mutta erilaiset ahmintaoireet olivat melko yleisiä sekä naisilla että miehillä. Masennuksen esiintyvyys sekä lihavuuden tai ylipainon riski ahmintahäiriöisillä olivat suurempia kuin terveillä. EDI-kysely soveltui hyvin ahmintahäiriön seulomiseen. Ahmintahäiriön matalan esiintyvyyden ja EDI-kyselyn seulontaominaisuuksien takia ahmintahäiriön seulominen kannattaa keskittää tiettyihin riskiryhmiin kuten masentuneet tai ylipainoiset nuoret naiset. Ravitsemusepidemiologisesta näkökulmasta ahmintahäiriön ja ahmintaoireilun välinen raja voidaan nähdä liian tiukkana, sillä ahminnan terveydelle aiheuttamia epäedullisia vaikutuksia esiintyy epäilemättä jo paljon ennen varsinaista ahmintahäiriödiagnoosia. Ahmintahäiriön tunnistaminen ja ehkäisy varhaisessa vaiheessa on tärkeää, jotta sen aiheuttamia terveyshaittoja voidaan ehkäistä.
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(2011)Johdanto: Raskaudenaikaisen D-vitamiinin puutoksen on havaittu vaikuttavan negatiivisesti syntyvän lapsen luuston kasvuun. Myös lapsen riittävä D-vitamiinin saanti on merkittävä tekijä lapsen luuston hyvinvoinnissa. Suomalaisten odottavien äitien D-vitamiinin saanti on usein puutteellista, eikä D-vitamiinia muodostu iholla talvikuukausina Suomen pohjoisen sijainnin vuoksi. Suomalaisten raskaana olevien naisten heikko D-vitamiinitilanne saattaa vaikuttaa lasten luuston terveyteen. Tavoitteet: Työn tavoitteena oli tutkia ovatko raskauden aikainen D-vitamiinitilanne, lapsen D-vitamiinitilanne ja D-vitamiinin saanti vuoden iässä yhteydessä luuntiheyden ja -mineraalipitoisuuden muutoksiin lapsen ensimmäisen elinvuoden aikana. Aineisto ja menetelmät: Raskausaikana rekrytoiduista 126 äiti-lapsi-parista vuoden iässä seurantakäynnille saapui 89 (69 %). Lapsilta otettiin verinäyte ja siitä määritettiin D-vitamiinitilannetta kuvaava seerumin 25-hydroksi-D-vitamiinipitoisuus (25(OH)D) immunoentsymometrisellä menetelmällä. Lasten sääriluu tutkittiin pQCT-menetelmällä. Vastaavat tutkimukset oli suoritettu sekä lapsille että äideille synnytyksen jälkeen. Äitien seerumin 25(OH)D-pitoisuus alkuraskauden aikana määritettiin THL:n keräämistä verinäytteistä. Lapsilta kerättiin kolmen vuorokauden ruokapäiväkirja sekä kyselylomake, joiden avulla selvitettiin D-vitamiinin saanti ruokavaliosta, D-vitamiinilisän käyttö ja taustatekijöitä. Äideille suoritettiin lyhyt haastattelu koskien lapsen terveyttä ja kehitystä. Tilastollinen tarkastelu suoritettiin SPSS (versio 16.0) –ohjelmalla. Korrelaatioanalyysilla selvitettiin minkä tekijöiden kanssa 1-vuotiaan luuston laatua kuvaavat muuttujat ja niissä tapahtuneet muutokset korreloivat. Regressioanalyysilla tutkittiin selittääkö raskausajan D-vitamiinitilanne, lapsen D-vitamiinitilanteen muutos tai lapsen D-vitamiinin saanti yhden vuoden iässä luustomuuttujien muutoksia. Monimuuttujamallin avulla tarkasteltiin, onko raskaudenaikainen D-vitamiinitilanne lineaarisesti yhteydessä luumuuttujien arvoihin. Tulokset: Lasten D-vitamiinin saanti ylitti keskimäärin suositukset (KA 12,3 ?g/vrk), mutta 20 %:lla seerumin 25(OH)D-pitoisuus oli riittämätön (< 50 nmol/l). Seurantakäynnin aikaan yhä imetetyillä lapsilla Dvitamiinitilanne oli heikompi kuin ei-imetetyillä (p=0,044). Luun mineraalimäärä (BMC, engl. bone mineral content) oli kasvanut eniten niillä lapsilla, joiden äitien D-vitamiinitilanne oli ollut heikoin raskauden aikana ja vähiten niillä, joilla D-vitamiinitilanne raskausaikana oli ollut riittävä. Tulos ei kuitenkaan yltänyt merkitsevälle tasolle (p=0.069). Muissa luumuuttujissa viitteitä yhteyksistä ei löytynyt. Taustatietoja tarkastellessa havaittiin merkitsevä negatiivinen yhteys raskausajan D-vitamiinitilanteen ja lapsen sairastamien nuhakuumeiden lukumäärän välillä (p=0.044). Johtopäätökset: Lasten D-vitamiinin saanti oli suositusten mukaista, mutta siitä huolimatta osalla lapsista Dvitamiinitilanne ei ollut optimaalinen. Erot BMC:n muutoksessa ryhmien välillä viittaavat saavutuskasvuun eli heikomman D-vitamiinitilanteen vaikutus luustoon kompensoituu BMC:n osalta ensimmäisen elinvuoden aikana. Pitkäkestoisia lisätutkimuksia raskausajan D-vitamiinitilanteen ja lapsen luuston yhteyksistä suuremmilla tutkimusotoksilla tarvitaan.
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(2011)The focus of the literature review of the study was on ice cream, different kinds of coatings used in the food industry and coating methods. In addition, the typical combosition of chocolate, rheological properties of liquid chocolate and the interaction between the consistency and rheological properties were reviewed. The objective of the study was to find out how consistency and coating temperature affects viscosity, yield value, solidification time and the amount of the coating layer in ice cream stick. The idea was primarily to find out how the amount of the coating layer could be controlled. Variables selected in this study were the amount of fat and emulsifiers in the milk chocolate coating and the coating temperature. The amount of coating layer, solidification time of the coating and viscosities and yield values of liquid coating were measured. The xperiment was planned using a Box-Behnken design. Results were calculated with regression analysis. Response surface methodology was used to estimate how the changes in fat amount, emulsifier amount and temperature affected the amount, solidification time, viscosity and yield value of coating. Increasing the amount of fat significantly decreased the amount, solidification time, viscosity and yield value of the coating. Increasing the amount of emulsifier decreased the amount, solidification time and yield value of the coating. Increasing temperature of the coating decreased the amount and viscosity of the coating, but increased solidification time of the coating. From the results, temperature, fat content and emulsifier content of the coating were found to affect the amount of the milk chocolate coating layer on an ice cream stick. Response surface methodology foud to be suitable method for investigating the amount of chocolate coating. Methods to control the amount of coating layer were examined by means of response surface methodology.
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(2013)Filamentous cyanobacteria taxa Nostocales and Stigonematales cells can differentiate into heterocysts nitrogen fixing cells when nitrogen is limiting the growth and into resting cells akinetes when nutrients decrease or the growth conditions become unfavorable for growth. Akinetes overwinter in the water sediments during the unfavorable growth time. When the growing condition improves akinetes germinate and can start a new cyanobacterial bloom. Akinete differentiation remains unclear. It is known from the literature that only a few akinete specific genes exist. First described akinete specific gene was avak. The morphological changes of akinete differentiation are known but the changes at molecular genetics level in regulation and differentiation remains unclear. The aim of this study was to design a method for akinete differentiation-related genes, avak, hepA and hap, for an Anabaena 1TU33s10 strain and to monitor the gene expression changes in a seven-week growth experiment. Primers for the differentiation related genes were designed based on the known whole genome sequence of the Anabaena 1TU3310 strain. In this study it was managed to design a quantitative reverse transcriptase polymerase chain reaction, qRT-PCR method, based on the genes involved in the akinete differentiation process. It was observed that gene expression changed when akinetes began to differentiate into the filaments. In the growth experiment II avaK-gene expression was increased 2-fold between the 14. and 30. days, and hap-gene showed 1.5 fold growth between 14. and 30. days. The number of akinetes was also increasing at the same time. In the growth experiment I heap-gene showed 1-8 fold growth between the days 21. and 27. –30. days when the number of heterocysts were also increasing. The number of akinetes was relatively low compared to number of vegetative cells which also explains the small expression fold-differences in the cultures during the experiment time when compared to expression fold-differences described in the literature. Designed method can thus also detect minor changes in gene expression. The designed and built qRT-PCR method can be used in the future for monitoring gene expression changes also for new akinete specific genes, and the method can be further optimized for screening natural water samples.
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(2013)Alkaline phosphatase (ALP) is an endogenous enzyme found in milk, which is inactivated at higher temperatures than vegetative bacteria and is thus used as an indicator of a successful pasteurisation. The ability of ALP to reactivate allows it to be found in milk products that are claimed to be pasteurised. The aim of this Master‘s thesis was to understand the reactivation behaviour of ALP in order to ascertain whether high levels found in milk products are correlated to a normal reactivation property of the enzyme or other possible reasons, such as a failed pasteurisation or contamination. This work also aimed to define the mean ALP activities found in specific commercial milk products and their deviation from the acceptable levels. Another scope was to determine the freeze stability of ALP to define its appropriateness for post-stored analysis. Lastly, the examination of ALP location in milk fat membrane globules was examined to interpret the variation of enzyme activity levels in products of different fat content. The experimental part of the Master‘s thesis was divided into three parts. The first part included the record of ALP activities of different commercial Finnish milk products which are analysed in different groups according to their fat content and product type. The second part concentrated on the heat-treatment of milk samples at different time-temperature relationships and followed the reactivation behaviour of ALP. The total micro-flora was taken into consideration in order to observe any relation between the increased ALP activities and microbial growth. ALP activities were measured by a fluorimetric method, a quick three minute method which has the advantage of being more accurate compared to colourimetric methods. The third part examined the fraction in which ALP activities are found in milk after separation and its freeze stability when stored at -79 ºC. Commercial cheeses showed a high ALP activity in Emmental thermised cheeses and an activity less than 10 mU/g in other cheese types and pasteurised cheeses. In commercial milks, UHT treated and those closer to expiration date, high ALP activities were found, while pasteurised milks had low activities below the higher acceptable levels. The reactivation property of milk samples that were heat-treated in ALP was not related with the microbial growth and was quicker when the milk samples were heat-treated at higher temperatures. After the separation of cream from whole milk samples, ALP activity was found in the skim milk part. In conclusion, ALP activities did not decrease significantly following freeze storage for a few days showing its stable freeze properties.
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(2016)Diabetes first time detected during pregnancy is called gestational diabetes (GDM). Diagnostic criteria for gestational diabetes differ from those of diabetes outside of pregnancy. In the year 2014 16 % of Finnish pregnant women had abnormal OGTT (oral glucose tolerance test) result. OGTT is the standard method for diagnosing GDM. GDM prevalence is increasing and it is mainly accounted for increasing body mass index among pregnant women. GDM predisposes both mother and child for perinatanal complications as well as health problems in their later life. In Finland GDM is diagnosed during early pregnancy or in general at the turn of the second and third trimester. There is no worldwide consensus of the justification of the early GDM diagnosis. Little is known about the patients with early GDM. The main goal of my master´s thesis was to describe lifestyle (nutrition and physical activity) and health of the early (pregnancy week 8−12) GDM study subjects and to compare these to other study subjects´ lifestyle and health. In addition the study examined which factors were accounted for the early GDM. The data of the master´s thesis came from the NELLI intervention study (Neuvonta, elintavat ja liikunta neuvolassa) which covered years 2007–10. The inclusion criteria of the study were factors known to increase the risk of GDM. The exclusion criteria included for example abnormal OGTT result during early pregnancy. Study subjects´ nutrition and leisure time physical activity (valid surveys) and health (anthropometric measures, blood pressure, blood tests) were followed during pregnancy. One year after delivery follow-up study was carried out. Master´s thesis data consisted of the records of the study subjects participating in the NELLI intervention study and subjects excluded from the study due to the abnormal early pregnancy OGTT. Data relative to early GDM subjects existed only for before bregnancy (lifestyle) or early pregnancy (health) and one year after delivery (lifestyle, health). In these time points variables representing early GDM and NELLI study subjects´ lifestyle and health were compared. Statistical methods used were Pearson´s chi-square test, Fisher´s exact test, independent samples T-test and Mann-Whitney U test, linear regression analysis, ordinal logistic regression analysis and logistic regression analysis. The factors accounting for risk of early GDM were increasing body mass index before pregnancy, age of at least 35 years before pregnancy and GDM or macrosomic newborn during previous pregnancies. High-density lipoprotein concentration of early GDM subjects during early pregnancy was lower than that of other study subjects. In addition total fat contributed more of the daily energy intake (E%) and low-fat dairy products and cheeses smaller portion of the diet before pregnancy of early GDM subjects than of other study subjects. Furthermore the nutritional goals (≥ 4/5) were fulfilled less frequently before pregnancy in the diet of early GDM subjects than in the diet of other study subjects. The group of early GDM subjects participating in the follow-up study was assorted hence the results of follow-up study have to consider cautiously. Mainly the same factors which are known to increase GDM risk at the turn of the second and third trimester accounted also for the risk of early GDM. Weight management before pregnancy seems to be the most important way to reduce the risk of early GDM. Some signals were also be noticed according to which early GDM subjects´ lifestyle and health markers differed unfavourably from those of other study subjects. In conclusion strong attention should be paid to counseling on lifestyle factors and follow-up of the health of early GDM patients both during pregnancy and thereafter.
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(2015)Genetic selection of broilers has produced heavier birds that grow faster, with consequent change in morphology and allometry (relative growth) of their body parts. Wooden Breast (WB) is a defect of the breast muscle that affects meat quality. Its cause is unknown, but heavy weight and/or rapid growth rate seem to be predetermining factors. The aim of this work was to study the differences in morphology and relative growth (allometry) between WB affected and unaffected birds. Random groups of a total of 350 male chickens of 5 hybrids were slaughtered at 7 different ages. Morphometric measurements of heart, liver, intestine, breast muscle, girth, coracoid, clavicle, keel and leg bones were analysed with a statistical software. Affected birds presented higher body weight, heavier, longer and thicker breasts and heavier livers than unaffected birds. On the other hand, unaffected birds presented longer legs, heavier intestines and hearts. Keel length, coracoid length and clavicle length did not present any difference between both groups. The comparison of allometric curves of affected and unaffected birds showed differences in almost all body parts, but the heart and liver. Clavicle was the only body part that presented a slower growth rate in unaffected birds, all the other body parts showed a higher growth rate. The relationship between breast thickness and clavicle, coracoid and keel lengths, had a great effect on the presentation of WB. Affected birds presented changes in morphology and growth, very similar to the ones caused by genetic selection. Genetic selection of broilers is very complex and dynamic and it may be possible that WB has several causes. It seems that one of them is the lack of support of the breast muscle, due to an impaired growth of its bone structure.
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(2015)Työssä tarkasteltiin sedimentin alumiini- ja rautaoksidien osallistumista fosforin sitomiseen kolmella eri alueella pohjoisella Itämerellä ja sitä kuinka sedimentin metallioksideihin sitoutuneet fosforifraktiot voidaan erotella peräkkäisten uuttojen avulla. Tutkitut näytteet oli otettu estuaarityyppisistä sedimenteistä Ahvenkoskenlahdelta, Perämereltä ja Saaristomereltä. Näytteitä uutettiin peräkkäin ammoniumfluoridilla, natriumditioniitilla ja natriumhydroksidilla. Käytetyt uuttoliuokset valittiin kirjallisuuden ja aiempien tutkimusten perusteella. Uutteista mitattiin fosforin, raudan, alumiinin ja mangaanin pitoisuudet ICP-OES-laitteistolla. Työn ensimmäisessä vaiheessa uuttoliuoksia lisättiin eri järjestyksissä ja tulosten perusteella uuttojärjestykseksi valittiin: 1) natriumditioniitti, 2) ammoniumfluoridi ja 3) natriumhydroksidi, koska näin pystyttiin parhaiten erottamaan alumiini- ja rautaoksidien sitoma fosfori toisistaan. Työn toisessa vaiheessa uutettiin kolmen eri alueen estuaarisedimenttejä valitulla uuttojärjestyksellä. Kirjallisuudessa on usein esitetty, että alumiinioksidit eivät olisi merkittävässä roolissa merisedimenttien fosforin sitomisessa vaan että alumiinioksidien sitomaksi määritetty fosfori voisi olla rautaoksidien sitomaa, mutta menetelmän epäspesifisyyden vuoksi tutkittu alumiinioksidien sitomaksi. Työn toisen vaiheen tulokset osoittivat, että alumiinioksidit osallistuvat fosforin sitomiseen estuaareissa. Estuaareihin hautautuneista sedimenttinäytteistä erottui alumiinioksidille spesifisellä uutolla oma fosforijakeensa, joka ei tulosten mukaan voinut olla peräisin rautaoksidien sitomasta jakeesta. Ahvenkoskenlahden näytteessä oli Saaristomeren ja Perämeren näytteisiin verrattuna suhteessa eniten alumiini- ja rautaoksidien sitomaa fosforia. Alumiinioksideilla havaittiin olevan enemmän merkitystä fosforin sitomisessa lähempänä rannikkoa, kun taas rautaoksideilla on enemmän merkitystä kauempana rannikosta.
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(2015)The objective of the thesis was to investigate the effect of carbohydrates on solubility, emulsifying, gelling and water holding properties of proteins. Faba bean is a readily available pulse crop with high protein content similar to soy bean and there is a lot of potential for a novel, high protein fermented gel product to be made from a pulse crop like faba bean. This is mainly due to its remarkable nutritional properties, functional properties and low cost, the demand for faba bean protein ingredients will grow. The current study was an attempt to develop pulse protein based products – emulsion (milk-like) and emulsion gel (yogurt-like) from faba bean. It seeks to expand the field of application of faba bean protein based products. Faba bean was pretreated, dehulled and milled. The flour was made into suspensions and the starch in faba bean was subjected to amylolytic treatments (addition of alpha amylase and glucoamylase) to breakdown the starch into smaller particles. These treated suspensions were then homogenized to obtain emulsion. A protein based gel network was produced with the gelation of amylolytically treated faba bean proteins. The emulsion properties, specifically droplet size, stability and activity were tested by PAMAS Particle Counter System. Light microscopy was applied to reveal the microstructure of emulsion and emulsion gel. Emulsion gel texture properties were studied by texture analysis. The emulsions were relatively stable over a period of a month and had white ‘milk’ like appearance. The emulsion gels prepared (amylolytic treatment) had slightly higher water holding capacities than the control A (entire starch present) and control B (starch removed by filtration) emulsion gels. Texture analysis of the emulsion gels showed that more force was required by probe to penetrate the yogurt produced from amylolytically treated samples and less force was required to penetrate the yogurt produced from controls A and B. The yield of the emulsion gels were higher for the amylolytically treated samples. It can be concluded that amylolytic treatment has increased the water holding capacity and also resulted in stronger gel systems.
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(2013)Cyanobacteria are phototrophic organisms. They usually occur in water but many species also live in terrestrial habitats, e.g. in symbiotic relationships with fungus. Inorganic phosphorus (Pi) is usually considered to be a limiting factor for the growth of cyanobacteria living in water, since cyanobacteria can use only Pi as a direct source of phosphorus. It has been shown that cyanobacteria have pho-regulon similar to that of Escherichia coli. Pho-regulon can transport and assimilate inorganic phosphate. Cyanobacteria usually produce a wide range of bioactive compounds, which can e.g. be toxic or prevent growth of other bacteria, fungi or yeast. Many of these compounds are produced by non-ribosomal peptide synthetases (NRPS). The aim of this study was to investigate changes in Anabaena sp. 90 proteome, and differences in amounts of bioactive compounds produced by the strain, while growing it in media with high (5,5 mg/l) or low (0,05 mg/ml) Pi concentration. Before moving the culture into two different Pi media, phosphorus storages of the culture were emptied by growing the strain in the media without Pi. In this study, 2D differential gel electrophoresis (2D-DIGE) coupled with LC/MS was used to study proteomes of the organism. Bioactive compounds were also analyzed by LC/MS. Anabaena sp. 90 was chosen because of its fully sequenced and annotated genome. The strain has been found to produce microcystins, anabaenopeptins and anabaenopeptilides. Eleven protein spots with significantly increased or decreased protein quantities were identified in the low Pi media. Ten of them were identified as proteins, which participate in bacterial stringent response. Stringent response is activated when culture is achieving the stationary phase. These stringent response proteins participate in the amino-acid metabolism and translation. One of the proteins was shown to be a ribosomal protein. In addition, the identified proteins included ribulose-bisphosphate carboxylase oxygenase (RuBisCO), which had a significantly lower concentration in the cells in low-phosphorous media. There were no significant differences in amounts of bioactive compounds when growing the culture in low and high Pi media. More replicates could be used, when the study of bioactive compounds is repeated.
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(2013)Cyanobacteria are aquatic and terrestrial organisms that have photosynthetic cababilities. Cyanobacteria are classified to five orders according to their morphology. These are Chroococcales, Pleurocapsales, Oscillatoriales, Nostocales and Stigonematales. Anabaena sp. 90 is a filamentous cyanobacterium in the order of Nostocales. A sample of this cyanobacterium was isolated from the lake Vesijärvi in 1986. Anabaena sp. 90 produces a variety of bioactive peptides such as microcystins, anabaenopeptins and anabaenopeptilides which are the most commonly studied of the peptides produced by the strain. Majority of the bioactive peptides are produced by non-ribosomal peptide synthetases (NRPS). The way these compounds affect cyanobacteria is currently unclear. Anabaenopeptilide deficient mutant (apd-) variety has been developed from the Anabaena sp 90 wild type (WT). The mutant is unable to produce anabaenopeptilides. The aim of my Master´s thesis was to study the changes in proteomes of WT and apd- strains by conducting a six day cultivation experiment. The purpose was to evaluate the possible differences in the amount of proteins that the different cultivation stocks were able to produce. The secondary purpose was to examine the transcription of anabaenopeptilide synthetase genes. Proteomic study was performed using a procedure called two dimensional differential gel electrophoresis (2D DIGE). The differences in the proteomes´ statistics were examined by using the Student´s t test. Transcription of anabaenopeptilide synthetase genes were studied using a reverse transcriptase polymerase chain reaction (RT-PCR). The data collected from these studies concluded that there were differences in the proteomes of WT and apd- strains. In eighteen cases there were significant differences in the protein amounts between the strains. The single protein counts were often higher in the apd- than in the WT strain. Anabaenopeptilide synthetase genes were transcribed in both strains which suggests that the mutation in the apd- strain did not hinder the ability of the strain to produce anabaenopeptilide transcripts. The identification of significant proteins would yield more detailed knowledge of the metabolical functions of WT and apd- strains.
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(2010)Tässä tutkimuksessa tarkasteltiin viljelykäytössä olevan happaman sulfaattimaan Ap- ja Bg1- horisonttien aggregaattien stabiilisuudessa tapahtuvia muutoksia neljän viikon tulvituksen aikana. Tulvitus estää maan kaasunvaihdon, mikä aiheuttaa hapen puutetta maaperässä. Tästä seuraa muutoksia maan kemiallisissa olosuhteissa, muun muassa maan rakennetta stabiloivan raudan liukoisuus lisääntyy. Tutkimus suoritettiin laboratoriokokeena. Aggregaattien stabiilisuuden mittarina käytettiin märkäseulonnassa irtoavien alle 250 ?m:n kokoisten hiukkasten sekä kolloidiaineksen (< 2 ?m) määrää. Märkäseulonnassa irtoavan maa-aineksen määrää selvitettiin gravimetrisillä mittauksilla sekä laservaloon perustuvilla menetelmillä. Työssä käytetyt laservaloon perustuvat menetelmät olivat dynaaminen valonsironta sekä partikkelilaskenta. Dynaamista valonsirontaa käytettiin kolloidiaineksen määrän mittaamiseen. Menetelmän ongelmana oli tulosten välinen suuri hajonta. Alle 250 ?m:n kokoisten hiukkasten määrää mitattiin partikkelilaskurilla. Tätä mittausta vaikeutti laitteen vaatima pieni partikkelikonsentraatio sekä suurimpien partikkelien jääminen mittauksen ulkopuolelle. Aggregaattien stabiilisuuden tarkastelussa käytettiin gravimetristen mittausten tuloksia. Tulosten perusteella Bg1-horisontin murut olivat huomattavasti Ap-horisontin muruja kestävämpiä. Tähän saattoi olla syynä raudan suurempi määrä Bg1-horisontissa. Ap-horisontin näytteissä sekä makro- että mikroaggregaattien stabiilisuus väheni kokeen aikana. Myös Bg1- horisontin näytteissä mikroaggregaattien kestävyys heikkeni, mutta ei yhtä paljon kuin Aphorisontin näytteissä. Ap-horisontin makroaggregaattien stabiilisuuden heikkenemiseen saattoi olla syynä niitä koossa pitävien juurten mikrobiologinen hajoaminen. Bg1-horisontin mikroaggregaattien hajoaminen oli mahdollisesti seurausta raudan liukenemisesta. Aggregaattien stabiloituminen kokeen loppua kohti aiheutui luultavasti johtokyvyn noususta näytteissä. Syyt stabiilisuusmuutoksiin kaipaavat kuitenkin vielä jatkotutkimuksia.
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(2012)The literature survey reviewed principles of oxidation of edible oils, adverse effects of lipid oxidation and analysis of volatile oxidation products by SPME-GC-MS. The main aim of the experimental research was to study the influence of relative humidity (RH) on the release of volatile oxidation products from spray-dried emulsions with natural and cross-linked casein as emulsifier. The release of volatiles was determined by SPME-GC-MS. The sub aims were to study the effects of stabilization time at specific RHs, of temperature and agitation speed during the SPME extraction. The spray-dried emulsions were oxidised at 40oC in order to reach a certain level of oxidation. Next, the powders were stabilised under five RHs (0%, 11%, 33%, 54% and 75%) for one or two weeks in order to observe the effect of the RH and the stabilisation time on the release of volatiles. After adjusting the RHs, volatile compounds were analysed by SPME-GC-MS. The following SPME extraction conditions were tested: C1: temperature 40oC, agitation speed 250 rpm, C2: 50oC, 250 rpm, C3: 40oC, 500 rpm and C4: 50oC, 500 rpm. Identification of the compounds was carried out by matching their MS spectra with the NIST database. Altogether 45 volatiles released from the powders could be identified, and 18 of them were found in most samples. RH had an important effect on the release of volatiles from the encapsulated samples. The highest release was always observed at 11% and 33% RH, whereas the lowest release was found at 0% and/or 75% RH, depending on the SPME extraction conditions. The stabilisation time did not have a significant effect on the release of volatiles in most RHs. During the SPME extraction step, elevation of the temperature from 40oC to 50oC, as well as the agitation speed from 250 rpm to 500 rpm, facilitated higher release. However, the effect of temperature was greater than that of agitation speed. Although it was suspected that cross-linking of sodium-caseinate would enhance retention of volatiles, our experiment showed greater peak areas of most volatiles from the cross-linked samples than from the natural ones. By controlling the SPME parameters, it was possible to obtain repeatable volatile compound results. The SPME-GC-MS method applied in this study can be reliably used to analyse volatile oxidation products from spray-dried emulsions. Only at very low or high RH the release of volatiles may differ from samples stored at 11% -54% RH.
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(2019)The purpose of this thesis was to study the antibiotic perturbations in bacterial populations. Perturbations are common in ecosystems and they can change the composition and functionality of a community substantially. The response of a community is governed by ecological and evolutionary factors: perturbations change the competitive ability of species in the community, but rapid evolution can further affect species fate. This thesis focuses more on the ecological effects. Understanding the community response to a disturbance would be interesting both from a general point of view and from the more practical approach of understanding natural communities under perturbations caused by antibiotics but also, for example, by climate change or chemicals. Thus far, most studies have been performed in one- or two-species systems, not taking into account the effects communities have on the fate of a single species. To study antibiotic perturbations, a multi-species bacterial community was exposed to a streptomycin pulse of three different levels concentrations. Changes in community composition were studied in the end of the pulse (ecological resistance) and after a recovery period (resilience) from the antibiotic perturbation comparing to the pre-perturbed communities. Further, the presence of species flow was manipulated to examine if it could enhance community resistance and resilience. Based on the analysis, even low antibiotic concentrations can have a long-lasting effect on community composition, but the magnitude of the effect is dependent on the concentration. Community diversity was recovered better than the composition, especially after the weaker perturbations. Species flow aids in community recovery but does not affect resistance. The results were relatively reproducible between replicate communities, and species traits steered the species fate in, pointing to deterministic ecological processes driving the community response. However, repeatability decreased in communities perturbed with the highest antibiotic concentration, which could point to evolution.
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(2017)The literature review illustrated the negative impacts of mold spoilage in baked goods and the significance of lactic acid fermentation used to prevent mold growth, with a special emphasis on the mechanism of antifungal metabolites produced by lactic acid bacteria. A brief introduction of the raw materials (faba bean and pearl millet) was also involved. The aim of this study is to explore the potential of different strains of lactic acid bacteria producing antifungal compounds during faba bean and pearl millet fermentation, to facilitate their application in baked foods with extended shelf-life. Different species of lactic acid bacteria isolated from faba bean and pearl millet in previous studies were used singly as a starter for sourdough fermentation. Antifungal assays were carried out on target molds and selected sourdoughs showing antifungal activity were analyzed to assess the nature of antifungal compounds (e.g. organic acids and proteinaceous compounds). All of the water-soluble extracts from sourdoughs were able to inhibit the growth of the indicator molds P. paneum and P. albocoremium, but not A. niger. This was in agreement with previous findings, showing that sensibility towards different antifungal compounds is not identical across different molds. The concentration of organic acids and the potential proteinaceous nature of the most active extracts was also established. It was hypothesized that the organic acids produced during fermentation can act in synergy with proteinaceous compounds and could contribute to the antifungal activity of faba bean sourdough fermented with L. sakei F1410 and L. mesenteroides I21 and of pearl millet sourdoughs fermented with P. pentosaceus A133 and A1231. Furthermore, small molecular peptides generated possibly through proteolysis of proteins in faba bean sourdough fermented with P. pentosaceus I02 and in pearl millet sourdough fermented with L. palantarum A103 could be responsible for the antifungal effect.
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(2019)The rapid emergence of drug resistant pathogens prevents effective treatment of diseases and threatens the lives of millions of people. Similarly, resistance to chemotherapeutic agents has been observed in several types of cancer. Therefore, screening for novel antimicrobial and antileukemic substances is urgently needed. Screening microorganisms for bioactive molecules has resulted in the discovery of several substances that are currently used for disease treatment. Cyanobacteria represent an ancient group of oxygenic, photosynthetic prokaryotes that produce a variety of functionally diverse and structurally complex natural compounds, some of which have already been used as source of inspiration in drug development process. In this study, I evaluated the antimicrobial and antileukemic potential of filamentous cyanobacteria against Gram-positive, Gram-negative and fungal potential pathogens and acute myeloid leukemia (AML) MOLM-13 cell line. Extracts showing antibiotic and/or antileukemic activity were subjected to reversed-phase HPLC and individual fractions were re-evaluated for their ability to kill the abovementioned pathogens and/or induce cell death in MOLM-13 cell line. Metabolites present in the active HPLC fractions were analysed by UPLC/ESI/Q-TOF and elemental compositions were obtained. Identification of metabolites was accomplished by searching online databases for compounds with identical elemental composition. Chemical structures were further confirmed by comparing mass spectrometry data with publicly available data. New bioactive metabolites, new variants of known metabolites and a number of yet unidentified metabolites exhibiting antimicrobial and/or antileukemic activity are reported herein. In detail, novel metabolites belonging to aromatic polyketides and their new variants were present in the active fractions of Nostoc sp. CENA69. The cyanobacterium Aliinostoc sp. CENA513 produced the recently discovered metabolite nocuolin A, a compound with antimicrobial and antiproliferative properties, lipids and unidentified lipidic compounds that showed only bactericidal activity against B. cereus. Interestingly, none of the abovementioned strains had any effect on the growth of Gram-negative pathogens. Planktothrix agardhii UHCC 0018 and Anabaena sp. UHCC 0187 strains showed only antileukemic activity. The majority of the bioactive fractions deriving from these two strains contained either lipids or pigments and their derivatives. The remaining active HPLC fractions of these two strains contained a great number of unidentified compounds. Further studies are required to identify the unknown compounds and purify the novel metabolites and antibacterial lipids. The results presented herein clearly show that Cyanobacteria are an emerging source of bioactive metabolites that can be used in drug development process or act as a source of inspiration for the production of novel synthetic drugs.
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(2015)The aim of this thesis was to validate the AOAC integrated total dietary fibre method (2011.25) for tomato. Additional purpose of this study was to update dietary fibre values in Finnish food composition database Fineli. The literature review focused on the background of dietary fibre analysis, method development and dietary fibre composition of vegetables. The method measures separately insoluble dietary fibre (IDF), dietary fibre soluble in water but precipitated in ethanol (SDFP) and dietary fibre soluble in water and not precipitated in ethanol (SDFS; oligosaccharides). The method includes a 16 hour starch hydrolyzing incubation that was presumed to stimulate enzyme activity in tomato. The effect of endogenous enzyme activity was examined with preliminary experiments, which included keeping the sample at room temperature before analysis, inactivation of enzymes with heat treatment and performing the analysis without incubation. Repeatability and reproducibility of the method were determined by analysing a pooled sample consisting of Finnish tomatoes. The amount of IDF was highest in samples prepared without incubation. In incubated and heat treated samples, and in samples kept at room temperature the amount of IDF was lower and the amount of SDFP was higher compared to the samples prepared without incubation. This was propably due to pectin depolymerisation and solubilisation by enzymes. Validation sample was prepared without heat treatment. Validation was performed with incubated samples, because standard deviation for non-incubated samples was markedly higher. The amount of TDF (total dietary fibre) in digested samples was 1.3 % (1.1 % IDF and 0.2 % SDFP). Oligosaccharides were found only in trace amounts. Repeatability of the method was 11 % (TDF), 13 % (IDF) and 23 % (SDFP). Reproducibility was 11 % (TDF), 12 % (IDF) and 17 % (SDFP). Repeatability and reproducibility were propably impaired by the inhomogeneity of the sample matrix. Uncertainty of the method was 26 %. The method was validated and proven to be fit for purpose.
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(2013)Soil contamination with oily products poses great healthy and environmental risks to the polluted sites. The remediation difficulty mainly comes from the complexity of hydrocarbons. Different kinds of remediation technologies have been applied for hydrocarbon removal from soil. New technologies especially in situ bioremediation technologies are emerging constantly. Soil assessment is a key step in the remediation processes since it provides information about the contamination level and potential risks. In the present study, hydrocarbon contaminated soil samples were collected from two sites (one site was contaminated by weathered oily sludge waste with some vegetated plots; the other was contaminated with fuel oil with short-chain hydrocarbons). The samples were analyzed for physicochemical properties and hydrocarbon degraders were enumerated. Four degrading strains were isolated from the samples and their 16S rRNA genes were sequenced. The samples and isolates were investigated to check the existence of three catabolic genes involved in petroleum degradation. The objective was to reveal the intrinsic bioremediation potential of contaminated soils by investigating the key remediation “players” i.e. the degrader microorganisms and catabolic genes. The coexistence of abundant degraders and diverse catabolic genes give the soil a good potential for bioremediation. In addition, the relationships between degrader counts, genes detection and soil contamination levels can reveal how the contaminants affect the indigenous microbial community. The differences between vegetated and nonvegetated plots can also suggest if vegetation with legumes has good potential for hydrocarbon bioremediation. According to the results, both sites were moderately contaminated with different hydrocarbon composition. In the landfarming site, the TPH depletion in vegetated fields was higher than the unvegetated bulk soil areas. However, the degrading microorganism counts had no significant differences between vegetated and nonvegetated plots. The hydrocarbon contamination level had no correlation with the degrader counts. In subsurface soils where aeration was quite limited, degrading microorganisms were much lower than those in surface soils. Catabolic genes were detected from the isolated strains but rarely from the contaminated soil samples. The contaminants co-extracted with soil DNA may inhibit the PCR-based gene detection. With more primer sets or primers targeting broader genetic diversity ranges, more detection results can be expected.
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(2013)The literature review presented the effects of the polyglutamate chain on the biological and nutritional properties of folates and the main methods used for folate assays, with a special emphasis on the approaches to studying intact polyglutamates. A brief introduction regarding safety aspects of folate fortification was also given. The aim of this study was to develop a UPLC-FLR/PDA method for simultaneous determination of polyglutamyl folate vitamers. Chromatographic conditions were optimised for the resolution of polyglutamyl 5-methyltetrahydrofolates and major naturally-occurring monoglutamates. Method validation was conducted for both the UPLC method and affinity chromatography. Applicability of the validated method was evaluated on lupin flour, faba bean flour, and dry yeast, which were subjected to preparatory treatments with and without deconjugation. In addition, the effects of the sequential modification of preparatory treatments on the folate content and composition were investigated by using both the UPLC method and Lactobacillus rhamnosus assay. A desirable separation of target polyglutamates and monoglutamates was successfully achieved on the BEH C18 UPLC column within 11 minutes. The optimised UPLC method showed satisfactory selectivity, linearity, and sensitivity for the determination of methylated polyglutamates in the femtomole range and monoglutamates in the picogram range. Affinity chromatography showed satisfactory recoveries for polyglutamyl 5-methyltetrahydrofolates, but not for 5-formyl polyglutamates. In all three selected foods, 5-methyltetrahydrofolate was the dominant folate vitamer. Meanwhile, the analysis of undeconjugated samples showed that in the intact methylated folate pools, pentaglutamate predominated in legume flours and heptaglutamate in dry yeast. In addition, different sequences of enzyme and purification pretreatments were found to significantly affect both the total measurable folates and the folate profiles. Our standard preparatory procedures comprising simultaneous treatments with amylase and conjugase, then protease and affinity purification resulted in the greatest yield of total folates, but UPLC analysis indicated incomplete deconjugation. However, a modification in which deconjugation was conducted as the last step enhanced hydrolysis efficiency.
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