Browsing by department "Avdelningen för livsmedels- och näringsvetenskaper"
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(2020)Johdanto Lihavuus on maailmanlaajuisesti merkittävä kansanterveydellinen ongelma. Lihavuus on seurausta pitkäaikaisesta painon noususta. Jotta lihavuutta voidaan ehkäistä, on painon nousuun yhteydessä olevat tekijät tunnettava tarkasti. Elintavat ovat yksi merkittävimmistä painon nousuun yhteydessä olevista tekijöistä. Aamupalan syöminen on yhdistetty terveellisempiin elintapoihin kuten esimerkiksi runsaampaan kasvisten käyttöön. Aamupalan syöminen on myös yhdistetty pienempään painoon lukuisissa poikkileikkaustutkimuksissa. Suurin osa tutkimuksista on kuitenkin tehty lapsilla ja nuorilla ja aikuisilla tehtyä tutkimusta on vasta kovin vähän. Lisäksi aamupalan syömisen yhteydestä painoon pitkällä aikavälillä ei ole paljon tutkittua tietoa. Tavoitteet Tutkimuksen tarkoitus oli selvittää, onko aamupalan syöminen yhteydessä painon ja painoindeksin muutokseen 50-vuotiailla aikuisilla 10 vuoden seurantatutkimuksessa. Lisäksi tutkimuksella haluttiin selvittää aamupalan syömisen yleisyyttä ja sen muutosta sekä aamupalan syöjien ja aamupalaa syömättömien elintapojen eroja. Aineisto ja menetelmät Tutkimuksen aineistona käytettiin Ikihyvä Päijät-Häme -tutkimuksen yhteydessä kerättyä aineistoa. Ikihyvä Päijät-Häme on 10 vuoden seurantatutkimus, jossa selvitettiin ikääntyvien päijäthämäläisten terveyttä ja hyvinvointia. Tutkittavat poimittiin satunnaisesti väestörekisteristä kunnan, ikäryhmän ja sukupuolen mukaan vuonna 2001. Tutkimushenkilöt kutsuttiin osallistumaan terveystarkastukseen ja lisäksi he saivat kaksi kyselylomaketta, joita oli mahdollista täyttää joko kotona tai terveystarkastusten yhteydessä. Terveystarkastukset suoritettiin vuonna 2002 ja niiden yhteydessä tutkittavilta mitattiin pituus ja paino. Tässä tutkimuksessa hyödynnettiin Ikihyvä Päijät-Häme -tutkimuksen yhteydessä kerättyjä tietoja elintavoista eli liikkumisesta, tupakoimisesta, kasvisten, hedelmien ja marjojen käytöstä, ruoanvalmistusrasvan käytöstä, leivänpäällysrasvan käytöstä ja maidon ja piimän käytöstä sekä tietoa mitatuista painosta ja pituudesta sekä painon ja pituuden avulla lasketusta painoindeksistä. Tilastolliset analyysit suoritettiin käyttämällä ristiintaulukointia, logistista regressioanalyysia sekä toistettujen mittausten varianssianalyysia. Tulokset Tutkittavien paino ja painoindeksi nousivat 10 vuoden seurannan aikana. Aamupalan syöminen ei kuitenkaan ollut yhteydessä painon tai painoindeksin nousuun. Aamupalan syöminen oli hyvin yleistä tutkittavilla. Tutkimuksen alussa noin 90 % tutkittavista söi aamupalan. Aamupalan syöminen yleistyi 10 vuoden aikana siten, että tutkimuksen lopussa aamupalan söi 95 % tutkittavista. Naiset söivät aamupalan miehiä useammin sekä tutkimuksen alussa että lopussa. Aamupalaa syövien ja aamupalaa syömättömien elintavat erosivat jonkin verran toisistaan molempina vuosina. Selkeimmin elintapojen ero näkyi tupakoinnissa siten, että aamupalaa syövät tupakoivat selvästi harvemmin verrattuna aamupalaa syömättömiin. Aamupalan syöjät käyttivät myös kolme kertaa todennäköisemmin kasviksia päivittäin verrattuna aamupalaa syömättömiin. Ero oli kuitenkin tilastollisesti merkitsevä vain tutkimuksen alussa. Aamupalaa syövien havaittiin käyttävän useammin rasvatonta maitoa ja piimää tutkimuksen alussa. Aamupalan syöjät myös liikkuivat useammin verrattuna aamupalaa syömättömiin tutkimuksen lopussa. Johtopäätökset Kaikkien tutkittavien paino ja painoindeksi nousivat tutkimuksen aikana. Aamupalan syömisen ei todettu olevan yhteydessä painon tai painoindeksin muutokseen 10 vuoden seurannan aikana. Muutamissa aikuisilla tehdyissä tutkimuksissa on havaittu yhteys aamupalan syömisen ja vähäisemmän painon nousun välillä. Tämä tutkimus ei kuitenkaan tue olettamaa, että aamupalan syömien olisi yhteydessä vähäisempään painon nousuun. Lisää tutkimusta aiheesta tarvitaan, sillä tähän mennessä aikuisilla tehtyä tutkimusta on hyvin vähän.
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(2020)Varhaisravitsemus on elintärkeää lapsen selviytymisen ja kasvun, sekä terveeksi, yhteiskunnan tuotteliaaksi aikuiseksi kehittymisen kannalta. Aliravitsemus aiheuttaa vuosittain yli kolmen miljoonan alle viisivuotiaan kuoleman, ja suhteessa syntyneisiin kuolleisuus on suurinta Afrikassa. Vaikka lasten ravitsemuksen edistäminen on kansainvälisesti todettu prioriteetti, lähes puolet kaikista alle viisivuotiaiden kuolemista voidaan yhdistää epäoptimaaliseen ravitsemukseen. Imetyskäytäntöjen edistämiseksi on tehty paljon töitä, mutta lisäruokakäytäntöjä ja niiden kehittämistä on tutkittu vähemmän. Tämän pro gradu -tutkielman tavoitteena oli selvittää opetusvideoita nähneiden alle kaksivuotiaiden lasten äitien ja kontrolliäitien välisiä eroja lisäruokatiedoissa, -asenteissa ja -käytännöissä. Lisäksi tavoitteena oli raportoida alle kaksivuotiaiden lasten ruoankäyttöä tutkimusalueilla. Tämä tutkielma on osa Helsingin yliopiston GloCal-projektia, jonka tarkoituksena oli kehittää naisten ja lasten terveyttä ja ravitsemusta edistävä opetusvideosetti. Keniassa kuvatut 47 swahilinkielistä videota olivat nähtävissä kuuden kuukauden ajan äideille ja lapsille suunnattujen terveyskeskusten odotustiloissa Nairobissa slummialueella ja Machakosin maaseutualueella Keniassa. Aineisto kerättiin poikkileikkausasetelmassa intervention lopussa syksyllä 2016. Kenialaiset ravitsemustieteilijät haastattelivat alle kaksivuotiaiden lasten äitejä paikallisella kielellä. Kaikki tilastolliset analyysit tehtiin IBM Statistics SPSS (versio 24) -ohjelmalla. Haastattelun aloitti 1005 henkilöä, joista 66 keskeytti haastattelun ja 40 ei täyttänyt sisäänottokriteereitä (n=965). Lasten ruokavalio koostui molemmilla alueilla pääasiassa viljoista, hedelmistä ja kasviksista. Proteiinipitoisten ruokien saanti oli vähäistä. Vain noin joka kymmenes kaikista 6–8 kuukauden ikäisistä ja alle puolet kaikista 9–23 kuukauden ikäisistä lapsista täytti WHO:n lisäruokinnan vähimmäissuositukset (MAD). Nairobin interventioryhmässä (NI) ateriatiheys, MF (6−8 kk p=0,002; 9−11 kk p<0,001 ja 12−23 kk p=0,002) ja ruokavalion monipuolisuus, DDS (ikäryhmittäin: p=0,025; p=0,002 ja p=0,013) olivat paremmat kuin kontrolliryhmässä (NK). Machakosin interventioryhmässä (MI) DDS oli parempi vanhimmassa ikäryhmässä (p=0,023) verrattuna kontrolliryhmään (MK). NI:ssä MAD oli keskimäärin parempi kuin NK:ssä (9−11 kk p=0,002 ja 12−23 kk p=0,022). NI:ssä lapset saivat yleisemmin lihaa, kalaa ja mereneläviä (ikäryhmittäin: p=0,017; p=0,001 ja p=0,007) ja öljyä (ikäryhmittäin: p=0,001; p<0,0001 ja p=0,002) verrattuna NK:ään. NI:n asenteet lisäruokien aloitusajankohtaan (p=0,006) sekä munien (p=0,001), palkokasvien (p<0,001), kalan (p=0,037) ja hedelmien (p=0,048) antamiseen puolivuotiaalle lapselle liittyen olivat paremmat verrattuna NK:ään. MI:n asenteet palkokasvien (p=0,011) ja kalan (p=0,013) päivittäisen tarpeellisuuden suhteen olivat paremmat kuin MK:ssä. Äitien tietämys ruokaryhmistä (hedelmät ja kasvikset p<0,0001 ja palkokasvit p=0,046), eläinperäisten tuotteiden hyödyistä (lapsen kehitys p=0,003 ja aivojen kehitys p=0,030) ja puuron sopivasta koostumuksesta (p<0,001) oli NI:ssä parempi kuin NK:ssä. Ryhmien välillä oli selvästi useampia tilastollisesti merkitseviä eroja Nairobissa kuin Machakosissa, ja alueellisten erojen selvittäminen olisikin hyvä jatkotutkimusaihe. Tutkielma osoittaa, että opetusvideoilla on potentiaalia edistää äitien lisäruokakäytäntöjä, -tietoja ja asenteita. Lisää tutkimusta kuitenkin tarvitaan esimerkiksi selvittämään äitien mahdollinen tuen tarve. Lisäksi vastaavien videoiden tutkiminen kontrolloiduissa olosuhteissa antaisi tarpeellista lisätietoa videoiden tehosta.
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(2020)Background: In adults, vegetarian and vegan diets have been associated with decreased cardiovascular disease (CVD) risk. At the same time, lower plasma LDL-concentrations are reported in vegans than in omnivores. Classification of a vegetarian diet can be challenging, as the diets vary in the degree and categories of the avoided food products. Recently, plant-based diet indices (PDI), such as the provegetarian food pattern, have been introduced as a priori method to study vegetarianism as a continuum. Plant-based dietary indices weigh positively foods derived from plant sources, whereas animal foods are weighed negatively. Greater adherence to PDI has been associated with lower CVD mortality and lower incidence of coronary heart disease (CHD). Meanwhile, little is known about the associations of plant-based eating and the risk of CVD in children. Aims: The aim of this thesis is to study plant-based eating as a continuous phenomenon in a group of Finnish preschoolers. Furthermore, the focus is on the animal source energy and its associations with dietary intakes, and cholesterol and bile acid metabolism. Materials and methods: In this thesis, the data from the cross-sectional MIRA Helsinki Study is used. In 2017, City of Helsinki started a pilot project, in which a vegan food option was offered in municipal daycare. At the same year, MIRA Helsinki Study was started to examine the nutritional status of children following a vegan diet. Altogether 42 children, aged 1–7-years, participated. At daycare, 18 of the children consumed a vegan diet, whereas 24 were omnivores. However, these diet categories did not apply to the child’s diet outside daycare. Children’s diet was assessed with 4-day food records and with food frequency questionnaires (FFQs). Anthropometric measurements were taken and fasting blood samples collected. Blood samples were analysed with standard laboratory tests. Gas-liquid chromatography (GLC) and liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) methods were used to examine serum cholesterol metabolism biomarkers and bile acids, respectively. For each food item (n=719) in the food record data, the weight proportion of animal content was estimated. The animal-origin energy content of each food item was calculated by multiplying the known energy content of the food item with the aforementioned score. The proportion of animal source energy (ASE) per subject across the 4-day food record was calculated by dividing the energy derived from animal sources with total energy intake. The correlations of ASE proportion with dietary intakes and surrogate markers of cholesterol and bile acid metabolism were investigated with the Pearson correlation analysis. A multiple linear regression model was used to test whether the ASE proportion explained the plasma LDL-cholesterol (LDL-C) concentration when controlling for the child’s sex and maternal education. In addition, the associations between the ASE proportion and serum concentrations of 20 bile acid variables were examined with the Pearson correlation coefficient. The Benjamini-Hochberg procedure was used to correct for multiple analyses. Results: Among all of the participants, ASE proportions ranged from 0.00 to 0.52, with a median value of 0.275 (that is, 27.5% of total energy derived from animal sources). Intake of animal source energy correlated positively with SAFA (r=0.815, p<0.000), cholesterol (r=0.707, p<0.000) and protein (r=0.493, p<0.001) intakes. There was a strong negative correlation between the ASE proportion and fibre intake (r=–0.836, p<0.000). In a linear regression model, adjusted for child’s sex and mother’s educational level, the model explained 44% (p<.000) of the variance in the plasma LDL-C concentration. Every 0.1 increase in the ASE proportion (10E% increase in energy derived from animal sources) was associated with a 0.32 mmol/L higher plasma LDL-C concentration. Associations of ASE proportion and cholesterol surrogate markers were present: a higher intake of ASE correlated with lower concentrations of cholesterol absorption markers. A similar negative association with ASE proportion was present for two out of four cholesterol synthesis biomarkers. In addition, the bile acid synthesis biomarker (7α-hydroxy-4-cholesten-3-one) correlated negatively with the ASE proportion. From the 20 serum bile acid variables studied only the ratio of tauro- to glyco-conjugated bile acids was significantly associated with the ASE proportion after correcting for multiple analyses. Conclusion: Among the study participants, animal source energy ratio was a powerful predictor of plasma LDL-C concentrations. Dietary patterns characterised by high intake of animal source energy were less likely to meet the dietary recommendations of fatty acid (SAFA and PUFA) intake. Our results on cholesterol metabolism need to be confirmed and replicated in future studies, which should include data on absolute measurements of cholesterol synthesis and absorption.
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(2020)There is growing concern about the world population growth and the sufficiency of protein resources. Edible insects could be an alternative protein source for human beings. The aim of this master thesis was to examine the sensory characteristics of a new home cricket (Acheta Domesticus) product and understand the attitudes of consumers towards edible insects. The aim was to investigate the impact of consumer familiarity with edible insect food products on purchase intention and expected liking. The roles of media trust and purchase activism were expected to affect the behavior of consumers. Besides these four indicators also two more were added. These were food neophobia scale and innovativeness. The data on consumer attitudes and perception towards insect food was collected by using an electronic form that was sent to different mailing lists. Total of 167 respondents were gathered, 141 women and 63 men. 53 participants attended the sensory analysis tests on the beginning of the year 2020, ages 18 – 62. The analysis of the data was done with SPSS Statistics version 25. The findings of this study indicate that consumer familiarity contributes to purchase activism, purchase intention and expected liking. In this study the media trust did not contribute. Food neophobia scores correlated negatively to the intention to buy, expected liking and willingness to recommend the product. Innovativeness correlated positively to intention to buy and expected liking, and as expected, innovativeness correlated negatively to food neophobia scores. As people learn more about the ecological and nutritional benefits of edible insects, their attitudes towards insect food become more positive and they are more willing to try and taste insect products. The new home cricket product, PANNU Sirkka by GRiiDY, turned out to be quite suitable for Finnish consumers taste. On the just-about-right scale (1–4) the average score was 3,3 – 3,8 of all the assessed attributes. Many of the open responses mentioned the product to be ‘tasty, delicious, surprisingly good and crispy’, for instance. To overcome the preconceptions of western consumers, there should be more occasions to try and taste insect food. Marketing efforts are best targeted to consumers who are neophilic and innovative and encourage them to be the early adopters of insect food.
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(2020)The usual dietary sources of vitamin B12 are animal-based foods such as meat, milk, fish and shellfish. Vitamin B12 is an essential water-soluble vitamin for humans, which have many necessary tasks in human body. People who lack animal foods like vegetarians and vegans might be at risk of vitamin B12 deficiency. Microorganisms are the only original sources of vitamin B12 in nature. Especially Propionibacterium freudenreichii synthesizes active form of vitamin B12 for humans. P. freudenreichii is GRAS -graded bacteria and it is safe to use in food matrices. Recently, it has been used for natural fortification of vitamin B12 in plant-based products by fermentation. However, the bioaccessibility of vitamin B12 of those products in human body is not very well known. In the beginning of the study, stability of different B12 vitamers were studied in different light and pH conditions. Vitamin B12 forms are very light-sensitive, especially its physiological forms methyl- and adenosylcobalamin. The aim of this research was to study bioaccessibility of vitamin B12 from P. freudenreichii cells and selected food products using a static in vitro assay. After the in vitro model, vitamin B12 content was analysed with UHPLC system. In addition of bacterial cell samples, bioaccessibility was studied also in some food samples, like bread, pasta and spray-dried powder, fortified with P. freudenreichii cells. In vitamin B12 stability studies, red light seemed to improve the stability of B12 forms. In yellow light methyl- and adenosylcobalamin degraded after 15 minutes. In red light they were detectable after hours of exposure. Methylcobalamin seems to be the most sensitive form of vitamin B12 vitamers. The study revealed that the bioaccessibility of B12 was very small (1,5 %) in P. freudenreichii cells but over 50% in whole bacterial broth. Heat treatment for the samples improved the bioaccessibility to some extent. In B12 fortified food samples, the bioaccessibility of B12 was very good (>70 %). The number of heat treatments and food structure could be one reason why bioaccessibilities in food samples are better than in cell samples. According to this research, in situ fortified food products could be a promising source of vitamin B12 in future.
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(2020)Milk foam is an essential part of coffee drinks such as cappuccinos. The foaming properties of milk can change during its shelf life. Milk used in coffee usually contains at least 2 % fat which can deteriorate its foaming properties. UHT milk can lose its sensory and foaming properties during its shelf life. In this thesis the change of properties of UHT-treated coffee milk called Barista milk were investigated. Barista milk is a commercial lactose free, homogenized milk meant to use with coffee. It has 2,0 % of fats and 3,5 % of proteins. The preservation of UHT barista milk was studied when milk was 4, 5, 6 and 7,5 months old. The foaming properties of barista milk were evaluated with automated foaming system. The volume of foam and its stability were measured as volume in a measuring glass. The structure of foams was also photographed and analyzed from photos. Nowadays plant-based drinks are important options for milk. Selected oat drinks for coffees were studied with same foaming methods as milk samples. The oat drink samples were kept in room temperature, fridge (+6 °C) and + 30 °C storage conditions. The tests were made when samples were 4, 8 and 10 months old. Barista milk as evaluated also with sensory evaluations. The sensory properties of barista milk were measured by tasting the milks referred to a fresh reference milk. Sweetness, bitterness, intensity of cooked flavor and fullness were evaluated from milks and cappuccino drinks made from the studied milks. In addition, a professional barista foamed the milks to makes cappuccinos and the drinks were evaluated. The preservation of milk did not affect its foaming properties or foam stability significantly. The foaming temperature affected the volume of foam more than the age of the milk. There was a slight change in the bubble structure of milk. The bubble structure was more uneven with older milk than fresh milk. Oat drinks foamed more, and the foams were more stable in all samples compared to milks of same age. The effect of foaming temperature was less meaningful with oat drinks than with milks. The sensory properties of milk did not change significantly during the study. The biggest change was the decline of cooked flavor in samples tasted as milk. The same decline was not detected when the milks were tasted as cappuccino drinks. An increase of bitterness was detected in the cappuccinos made by a barista when the milk was 6 months old. According to these results the shelf life of barista milk can be lengthened from 4 months to 5 months.
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(2020)Heavy traffic and transportation of crude oil makes the Baltic Sea vulnerable to accidental oil spills. Currently mechanical removal is the recommended response method in the Baltic Sea region. However, in bad weather conditions, mechanical oil removal can be challenging, and it may be justifiable to consider alternative response methods in order to protect valuable natural sites. Chemical dispersants are mixtures of surfactants and solvents and are used to treat spilled oil in marine environments. Dispersants break oil slicks into small droplets, which are more readily available for microbial biodegradation. Large-scale studies on the effects of dispersants on microbial communities and biodegradation rates have not been conducted in the Baltic Sea. During this 40-day microcosm study, native microbial communities from the Gulf of Finland were exposed to crude oil, dispersant or their combination. Additional nutrients were not supplied during the study. The experiment was carried out at 10 °C, and samples were collected at days 1, 2, 5, 14 and 40. The amount and expression of genes related to microbial abundance, oil biodegradation and nutrient cycling was assessed by quantitative PCR. Extracellular enzymatic activities of microbes were studied utilizing high throughput robotics. The results indicated that microbial response was primarily elevated in samples containing dispersant. Dispersant was degraded almost completely during the study period. Biodegradation of C21-40 hydrocarbons in crude oil was not enhanced with the addition of dispersant. On genetic level, the abundance and expression of alkane monooxygenase gene (alkB) was elevated in samples with dispersant, whereas the abundance and expression of polycyclic aromatic ring-hydroxylating dioxygenase gene (PAH-RHD) was enhanced also in samples containing crude oil.
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(2020)Wheat bread is one of the most discarded food at the global level. To fulfill the goals of waste reduction and increase the circular economy activities, the re-utilization of bread still fit for food in the food chain is a priority. However, the utilization of wheat bread waste in the food chain is challenging. Lactic acid bacteria (LAB) fermentation has been recently studied as a potential processing method for bread waste slurry and applied as a dough ingredient in bread production. In LAB fermentation, functional and bioactive compounds can be produced. Some LAB strains can produce γ-aminobutyric acid (GABA), a neurotransmitter in animals’ central nervous system with multiple physiological functions. GABA has received much attention due to its numerous beneficial bioactivities. Currently, information on GABA biosynthesis by LAB fermentation in bread substrate is not available. In this thesis, the effects of LAB strain selection and fermentation substrates in waste bread fermentation were studied. Four different fermentation trials using wheat bread as substrate were performed to select the best LAB strain, optimize bread matrix composition, and fermentation parameters for GABA production. Microbial growth, pH, total titratable acidity, organic acids (High Performance Liquid Chromatography ), sugar composition (High-Performance AnionExchange Chromatography and Pulsed Amperiometric Detection), and GABA content were assessed. Among the conditions tested, the addition of wheat bran as a nutrient source improved the GABA production most significantly. Thus, this condition was upscaled for bakery uptake and used in a baking trial to produce value-added bread containing GABA. LAB fermentation of waste bread to produce functional bioactive compounds was proven to be a potential processing method applicable to bakery products. The combination of two food sidestreams, waste wheat bread and wheat bran, can be implemented as a strategy to re-utilize food by-products in the food chain.
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(2020)Wines are treated to ensure their quality and preservation in the winemaking process. Treatments also have their drawbacks. Premium winemakers have often avoided filtration because it is supposed to cause a loss of taste. Sulfurization of wine is important, for example, for microbiological quality, but it is assumed to reduce the fruity aroma of wines. The purpose of the literature section was to investigate in general the effects of the wine-making process on the volatile compounds of wines. The interest was to find out what happens in winemaking and what compounds are formed at different stages of the process. The literature section also looked at volatile compounds, their analytics and SPME technology. The aim of the experimental part of the work was to develop a research method using headspace-solidphasemicroextraction-gaschromatography-massspectrometry (HS-SPME-GC-MS) technology and to find out the aroma composition and possible differences of the receiving sample and the bag-in box (BIB) -packaged wine. Indicator compounds for volatile compounds were determined from Chardonnay and Cabernet Sauvignon wines using the HS-SPME-GC-MS method developed for the study of Cabernet Sauvignon wine. In the optimization of the method, the functionality of SPME fibers, the GC temperature program and the sample preparation were studied. Receipt, tank, and BIB packaging samples were collected for examination of the wines. The samples were analyzed by HS-SPME-GC-MS and the results were processed by principal component analysis (PCA) as well as other statistical methods. Receipt and BIB packaging samples from Cabernet Sauvignon wine were not divided into clear groups based on PCA. The model best describing the changes in the compounds was achieved with the profile of volatile compounds: ethyl acetate, 1-propanol, isoamyl alcohol, 2-methylbutanol, butanoic acid ethyl ester, isoamyl acetate, hexanol, hexanoic acid, octanoic acid ethyl ester and octanoic acid. In Cabernet Sauvignon wine, almost all the amounts of volatile compounds remained fairly constant as the process progressed. In 1-propanol, ethyl ester of butanoic acid and ethyl ester of octanoic acid, a decrease in the amount was observed between the receipt sample and the BIB packaging sample. In contrast, the amount of 2-methylbutanol and octanoic acid increased when receiving and BIB packaging samples were compared. Receipt and BIB packaging samples of Chardonnay wine were distinguished by PCA. The model best describing the changes in the compounds was achieved with the profile of volatile compounds: ethyl acetate, isoamyl alcohol, 3-methylbutanol, 2-methylbutanol, butanoic acid ethyl ester, isoamyl acetate, hexanol, hexanoic acid, benzene alcohol, octanoic acid ethyl ester, octanoic acid ethyl ester, octanoic acid ethyl ester. The amounts of volatile compounds studied in Chardonnay wine remained fairly constant. Octanoic acid ethyl ester, benzyl alcohol and decanoic acid decreased as the process. The results of the study show that the wine processing process affects the flavorings of Cabernet Sauvignon and Chardonnay wine. The HS-SPME-GC-MS method showed a reduction in several compounds, but previous studies have shown that this change has not been detected by sensory evaluation.
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(2020)Tämän tutkielman kirjallisuusosassa on selvitetty aiempien tutkimusten perusteella kaasutainnutuksen ja sähkötainnutuksen vaikutusta vertymien syntyyn, on myös tutkittu mm. aiheeseen liittyviä hyvinvointi asioita. Verenpurkauma syntyy verisuonten ylipaineen vuoksi lihakseen, ylipaineen tässä tapauksessa aiheuttaa tainnutus. Verenpurkaumat tainnutuksen yhteydessä aiheuttavat lihan laatuongelmia ja ovat eläimen kohtelukriteerinä ei toivottu ilmiö. Verenpurkaumia esiintyy enemmän sähkötainnutuksessa kuin kaasutainnutuksessa. Kaasutainnutus puolestaan on kyseenalaistettu useaan otteeseen tainnutusmenetelmänä eettisistä syistä, mutta teollisuus käyttää lähinnä CO2-tainnutusta sen nopeuden takia. Kokeellisessa osassa tutkittiin kahden erilaisen kaasutainnutusmenetelmän vaikutuksia vertymiin ja vertailtiin niitä. Samalla tutkittiin eri SEUROP-luokkien eroja sikojen vertymien esiintymiseen samalla aineistolla. Ruhon koostumuksella ja SEUROP-luokituksella on myös vaikutusta vertymiin aiemmin tehdyissä tutkimuksissa sähkötainnutuksessa, mutta kaasutainnutuksessa ei ole vastaavia tuloksia. Jalostustyön on arveltu olevan yhtenä selittävänä tekijänä, vähärasvaisuus ruhossa on korreloinut vertymiin. Verenpurkaumien esiintymiseen vaikuttavia tekijöitä joita kaasutainnutuksessa on mainittu aiemmissa tutkimuksissa mahdollisina syinä ovat stressi, väärä kohtelu, huono tilojen suunnittelu, jalostus, rotu, sukupuoli, pistoon kulunut aika ja tainnutus, joita ei voitu tässä tutkimuksessa sulkea pois. Kokeellisen tutkimuksen tulosten perusteella ei saatu tilastollisesti merkitsevää eroa hiilidioksidiryhmätainnutus- ja karusellitainnutussysteemin välille. Aikaisempien tutkimusten perusteella on huomattu, että on myös hankala kalibroida kaikki tekijät, jotka ovat mahdollisesti vaikuttavat vertymien syntymiseen.
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(2020)In general the amount of fat in cow’s milk, what consists mostly of fatty acids, is about 4%, and more than half of the milk fatty acids are saturated. Dairy fat, due to its saturated fat and cholesterol content, is related to the risk of cardiovascular disease. Moreover, energy from fat can also be related to obesity. These relations also concern cow’s milk, however, its fat content remains around 4% and besides fat, there are a lot of positive effects on health, as milk is a good source of some vitamins and minerals. Milk consumption in Finland per capita has been the largest in the world for many years. There is also a market for milk substitutes, i.e. non-dairy drinks, produced mostly from oat, soy, and almond. This master’s thesis focuses on cow’s milk fat content and its relations to human health, especially the cardiovascular health and obesity. According to the hypothesis, consumer attitude towards cow’s milk is strongly affected by assumptions associated with the impact of dairy fat on health as well as the impact of dairy industry on climate change. The aim of this research was to study how detrimental or beneficial the dairy fat in milk is for human health on the basis of cow’s milk chemical composition, health related reports by authorities, research findings, historical perspectives, and consumer preferences. According to the literature, the chemical composition and nutrients properties of whole milk show that more nutrients of health benefit are present in comparison than of detrimental compounds. Most of present evidence suggest that milk and dairy products have neutral or beneficial effect on human cardiovascular health alhtough it is generally recognized in dietary recommendations that saturated fat is a risk factor for cardiovascular disease. The experimental part investigated Finnish consumers attitudes and preferences regarding milk consumption and overall preferences and issues affecting attitude toward food choice. It appears that the study hypothesis partly refuted, as the majority of participants were not much affected by assumptions associated with the impact of dairy fat on health. However, the impact of dairy industry on climate change was a very important issue related to attitude and preference regarding milk consumption. The majority of the study participants made their choice of drinking milk on the basis of taste, and the impact on health was considered mainly as beneficial rather than detrimental.
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(2020)Introduction Kenya has recently acquired lower-middle income country status and is facing the triple burden of malnutrition. There is a shortage of data on food intake habits of children and adolescents especially in the rapidly changing urban environments. To be able to reliably measure food intake, one must be able to accurately estimate food portion sizes. Children’s ability to recall portion sizes consumed can vary widely. When a photographic food atlas designed for children with applicable portions is used, it can improve children’s estimation of food portions. Objectives The aim of this study was to develop a photographic food atlas to be used in assessing portion sizes among Kenyan adolescents aged 9-14 years living in urban areas, to support a quantitative 7-day food frequency questionnaire. The second aim was to assess the usability of the atlas amongst 9-14-year-olds and professionals working in the field of nutrition. Methodology A steering group of Finnish and Kenyan nutritionists was formed to oversee the development of the atlas. Literature and other official documents were reviewed to identify the most commonly consumed foods among 9-14-year-old Kenyans. To obtain weighed portion size data, participants were recruited in Nairobi sub-counties Embakasi Central and Langata to represent low- and middle-socioeconomic status respectively. Twenty-one participants aged 9-14 years participated in the weighing of portion sizes, food portions from street markets were also weighed. Three portion sizes (A, B, C) were calculated for most of the 88 food items in the photographic food atlas. Portion B was the average of all weighed portion sizes, portion A was half of B, and portion C was one and half times B. Cooking demonstrations were arranged with the families of participants and the food portions were weighed out and photographed. A photographic food atlas was compiled, and its usability was tested amongst eight adolescents and four nutrition professionals. The usability survey consisted of Likert scale and open-end questions to ascertain acceptability of the atlas. Verbal feedback and observations were also recorded. Results Based on the usability survey, the photographic food atlas received the Usability Score of “OK” and “Good” from adolescents and nutrition professionals respectively. All eight adolescents agreed that the atlas helped them recall portion sizes, but half disagreed and one was unsure whether they could use the atlas on their own. All four professionals agreed they would use the atlas in their work, but all found the quality of photographs poor. Two adolescents disagreed when asked if the portion sizes were small enough and one disagreed when asked if the portion sizes were large enough. However, all professionals agreed that portion sizes were reasonable for the age group. Professionals gave verbal suggestions on improvements, for example, which foods were missing, how to adjust layout as well as the shapes of portion sizes. Conclusion An atlas consisting of 88 most commonly consumed Kenyan foods was developed based on weighed portion sizes of 9-14-year-old Kenyans. The shapes of portion sizes as well as range of portion sizes were crucial for its usability. Poor picture quality hampered recognition of pictures. Clear instructions and explanation of the purpose of the atlas were crucial. A second version of the atlas was developed based on the feedback. The updated atlas, including 173 food items, was used in a cross-sectional study in Nairobi. Further research is recommended to validate the photographic food atlas in order to identify the possible bias it may introduce to portion size estimation.
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(2020)The literature review highlighted the principles of microencapsulation and spray drying, with emphasis on the properties of highly oxidizing oils, protein interface modification, and mechanism of lipid oxidation. The major aim of the research was to study the chemical and physical stability of microencapsulated flaxseed oil (MFSO) during storage under controlled relative humidity conditions (0%, 11%, 33%, 54%, and 75%RHs) and compare the results to bulk flaxseed oil (FSO). Microencapsulation was done by spray drying of non-cross linked (NCL) and transglutaminase cross-linked (CL) Na-caseinate FSO emulsions. Oxidative stability was examined through changes in physical and chemical properties of MFSOs and FSO as influenced by different RHs and storage periods. Chemical analyses were used to analyze the peroxide value (PV), fatty acid profile, γ-tocopherol, carotenoid and chlorophyll, phenolic compounds, and secondary oxidation products (hexanal and propanal) in MFSOs and FSO. Degree of secondary oxidation was determined by static headspace gas chromatography while the morphology of MFSOs was examined by scanning electron microscopy. Results showed that at dry condition (0%RH), surface lipids of CL and NCL MFSOs were unstable and more susceptible to oxidation after 17 weeks storage. Release of hexanal and propanal were higher for NCL than CL microencapsulated flaxseed oil which suggested that interfacial cross-linking of Na-caseinate was efficient. At high moisture condition (75%RH), MFSOs were oxidatively stable owing to their low PVs and structural transformation from porous structure to agglomerates or sticky form. High amounts of alpha-linolenic acid and γ-tocopherol were detected in FSO and MFSOs, and only minor losses occurred throughout storage period and under different RHs. FSO also contained considerable amounts of carotenoid and phenolic compounds but low in chlorophyll content. Oxidative stability of interface and matrix elucidated that humidity conditions considerably influenced the chemical and physical properties of CL and NCL MFSOs.
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(2020)The literature review of this thesis focuses on cooking loss and factors effecting it as well as low-temperature long-time (LTLT) cooking and how it effects meat. Reactions in meat during heating and their effects on meat products quality were also studied. The aim of the experimental research was to find the optimal strip size for one sous vide process to optimize cooking yield and sensory quality. To do so, pre-testing with several different strip sizes were performed and then one strip size was selected. With this strip size tests with 3 different meat types (chicken, pork and beef) were executed. The tests comprised 10 batches of around 100 kg of meat each type and both strip sizes totaling 60 batches with total weight around 7600 kg. The sensory evaluation was made with a panel of 15 workers from the company to determine if any changes occurred regarding the sensory quality. Every meat type was tasted and evaluated using a scale with a free line segment of 10 cm. The results were measured and the difference between the same type of samples were multiplied with 10 to achieve a difference measured in %-units. Every type of meat had higher cooking yield with larger strip size. Chicken improved the most, pork second and beef the least. The effects on sensory quality were moderate. Chicken and beef became less tender and pork improved, while juiciness of every type improved with bigger strip size. Chicken improved 31.9 %-units, pork 9.8 %-units and beef 6.7 %-units in cooking yield. Chicken overall acceptance seemed to have improved 0.3 %, pork 7.0 % and beef 1.7 % according the sensory evaluation.
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(2020)Applying organic amendments to agricultural soils holds a potential to mitigate climate change by increasing soil carbon stock. It may also provide other benefits, such as enhanced nutrient cycling along with improved soil quality and fertility. Aim of this study was to determine whether utilizing organic soil amendments has effects on soil aggregates and root-associated fungi, both of which are associated to increasing soil carbon stocks. Soil and oat (Avena sativa L.) samples were obtained from a field experiment established in Parainen, South-West Finland in 2016 on a clay (54 % clay) soil. Studied treatments included four organic soil amendments (two wood-based biochars and two fibrous by-products of paper industry), mineral fertilization control soil and untreated control soil. Sampling was done two years after the amendment application, in 2018. Soil sampling was done after the harvest and plant sampling at three timepoints (June, July and August). Soil aggregates were separated from the bulk soil by wet sieving to determine their stability and size distribution. Carbon content of aggregates, as well as topsoil (0-5 cm) carbon stocks were quantified. Oat roots were stained and colonisation rate of different intra-root structures formed by root-associated fungi (arbuscular mycorrhizal fungi and dark septate endophytes) determined with microscope. Studied organic soil amendments did not affect soil aggregate structure or carbon content of aggregates. Nevertheless, C/N-ratio of some of the studied samples as well as larger soil carbon stock imply that other one of the studied biochars could have increased soil carbon content. When observing fungal data by month for between treatment differences, AM arbuscules were found to be most common in untreated control soil in August. When monthly fungal structure observations from all the studied treatments were combined, clear change in intra-root structures was detected (likely due to seasonal dynamics of fungi); AM arbuscules were more common in June and July, whereas DSE structures predominated in August. Large variation in the field together with methodological constraints might hide some effects of organic amendments and to verify their impacts, more research is needed. Based on the results gained in this study, effect of organic soil amendments seemed to be neutral on both soil aggregates and root-associated fungi. Since no adverse effects were detected, studied soil organic amendments could be utilized as recycled fertilizers.
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(2020)Background and aim: Colorectal cancers (CRC) are the third most common type of cancer in men and the second most common in women worldwide. The risk for CRC is influenced by lifestyle factors, especially diet. The effect of diet on CRC risk is thought to be mediated by the liquid phase of the feces called fecal water (FW); the components in food or produced from food by the microbiome must be in soluble form to have an effect on the colon epithelial cells, especially on the proliferating cells at the bottom of the colonic crypts, and consequently on CRC risk. In this study, we examined how viability of cells from human colon cancer cell line HCA-7 was affected, when the cells were exposed to FW extracted from fecal samples from study participants eating diets with emphasis on either animal or plant protein sources. Additionally we tested, whether body mass index (BMI), pH of the FW, amount of N-nitroso compounds in feces (NOC), or intake of fiber, protein, calcium or energy correlate with viability. Materials and methods: 146 healthy voluteers (age 20–69, BMI 18,5–35) were randomly assigned to three intervention diet groups for 12 weeks. Protein content of the diets (target 17 E%) came from animal and plant sources in proportion of 70/30 % (ANIMAL-group, n=46), 50/50 % (50/50-group, n=44) and 30/70 % (PLANT-group, n=44). Food consumption was assessed using 4-day food records kept by the participants before and at the end of the intervention period. Fecal samples were collected from the same time periods. Fecal samples were diluted with water in ratio of 1:1 and homogenized, homogenate was ultracentrifuged, pH of the supernatant i.e. FW was measured and finally the FW was filtered sterile using a 0,22 μm filter. HCA-7-cells were first incubated roughly 24 h on 96-well cell culture plate in growth medium so that the cells were attached to the plate. Then three parallel FW samples in three different dilution (10 vol-%, 20 vol-% and 30 vol-%) from each study participant were added on to the plate, and the plate was further incubated exactly 24 h. After that, the amount of living cells was measured colorimetrically using WST-8-reagent. Viability (%) was determined by calculating the proportion of living cells in sample containing wells compared to the living cells in the control wells. Statistical significance of the differences of viability between the diet groups was tested by analysis of covariance (ANCOVA) using the viability at the baseline as covariate. Correlations were analyzed using Pearson’s correlation test. Results: FW samples were obtained from134 study participants. There was a statistically significant difference in viability between the groups’ means in samples with FW content of 30 vol-% (ANCOVA p=0,005). Viability (%) was smallest in the PLANT-group (co-variate adjusted mean 30,0 ± 1,9), and in the reciprocal comparison it differed from both the ANIMAL-group (37,8 ± 1,8; p = 0,011, Bonferroni correction) and the 50/50-group (37,1 ± 1,8; p = 0,021). At the end of the study, there were statistically significant correlation (p < 0,05) between viability and BMI in all of the FW contents (10 vol-%: Pearson correlation coefficient R = 0,210; 20 vol-%: R = 0,366; 30 vol-%: R = 0,319), pH of the FW in the FW contents of 20 vol-% (R = 0,204) and 30 vol-% (R = 0,249). The intake of protein (g/d) correlated in contents of 10 vol-% (R = 0,199) and 30 vol-% (R = 0,181). Also, the intake of protein in proportion to energy intake (E%) correlated in contents of 10 vol-% (R = 0,179) and 30 vol-% (R = 0,236). The intake of fiber, calcium and the amount of NOC:s in feces did not correlate with viability. Conclusions: In this study, the FW from the PLANT group reduced the viability of HCA-7 cells in vitro compared to the FW of the 50/50 ja the ANIMAL groups. This could indicate that increasing the consumption of plant-based protein sources and decreasing that of animal proteins may decrease the risk of CRC. To strengthen the current results, the exposure experiments should be replicated also using different colon cancer cell lines and a normal-like control cell line.
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(2020)Tausta: Tietoa väestön ruoankäytöstä tarvitaan väestön ravitsemustilan arviointiin ja seurantaan. Eri elintavoista ja sairauksien riskitekijöistä ruoankäyttö on yksi haastavimmin tutkittava ja mitattava tekijä. Päivittäistavarakauppojen ostotiedot tarjoavat uudenlaisen, objektiivisen ja edullisen aineiston väestön pitkäaikaisen ruoankäytön ja kulutustottumusten tutkimiseen. Suomessa päivittäistavaramarkkina on keskittynyt, joten jo yhden ketjun tiedoista voidaan saada kattavasti tietoa suomalaisten ruokaostoista. Aiemman tutkimuksen perusteella näyttäisi siltä, että tutkielmassa käytettävän LoCard -aineiston tapaista, automaattisesti kanta-asiakasohjelmaan tallentuneita ostotietoja ei ole aiemmin käytetty tässä laajuudessa väestön ruokailutottumusten ja ruoankäytön arvioimiseen. Tavoitteet: Tämä tutkielma on osa Helsingin yliopiston ja Tampereen yliopiston LoCard -tutkimushanketta, jossa yhteistyössä S-ryhmän kanssa hyödynnetään S-asiakasomistajien ostotietoja terveys- ja yhteiskuntatieteellisessä tutkimuksessa. Tutkimuksen tarkoituksena on tarkastella eläinkunnasta peräisin olevien elintarvikkeiden ostoja LoCard -aineistossa ja vertailla kulutustietoja Luonnonvarakeskuksen (Luke) ravintotaseen sekä Tilastokeskuksen kulutustutkimuksen tietoihin. Tarkastelun kohteena ovat liha, kala, kananmuna, maito ja maitovalmisteet sekä voi. Tavoitteena on ostojen ja ravintotaseen sekä kulutustutkimuksen kulutuksen vertailun pohjalta arvioida LoCard -ostoaineiston validiteettia ruoankäytön näkökulmasta ja pohtia voitaisiinko automaattisesti kertynyttä ostodataa hyödyntää elintarvikkeiden pitkän aikavälin kulutustietojen tarkastelussa ravintotaseen ja kulutustutkimuksen rinnalla. Aineisto ja menetelmät: Tutkimuksen pääaineistona oli erillisellä aineistopyynnöllä saatu osa-aineisto LoCard -tutkimuksen ostoaineistosta. Pyydetty aineisto sisältää Prismoista, S-marketeista, ABC-marketeista sekä Alepa- ja Sale -myymälöistä ostettujen eläinperäisten elintarvikkeiden ostomäärät tietojensa luovutukseen suostuneilta pääkortinhaltijalta vuoden 2017 ajalta sekä tietyt taustamuuttujat. LoCard -ostoaineiston tuoteryhmät luokiteltiin ravintotaseen pohjalta uusiksi ruokamuuttujiksi ennen aineistopyyntöä. Ostoaineistosta laskettiin eri ruokamuuttujien tunnusluvut ja arvioitiin ostot henkilöä kohden jakamalla kotitaloustason ostot kotitalouden koolla kaiken kokoisten kotitalouksien kesken sekä vain yhden hengen kotitalouksien keskuudessa. LoCard -ostoaineistoa verrattiin vuoden 2017 ravintotaseeseen sekä vuoden 2016 kotitalouksien kulutustutkimukseen arvioimalla ruokamuuttujien keskimääräinen kulutus (kg tai l/hlö/vuosi) pääryhmätasolla kaikista aineistoista ja laskemalla prosentuaaliset erot kulutuksessa eri aineistojen välillä. Lisäksi tarkasteltiin eri ruokamuuttujien suhteellisia osuuksia pääryhmien kulutuksesta aineistoittain. Tulokset: LoCard -aineiston tutkittavista (n=21 380) naisia oli 13 958 (65 %) ja miehiä 7422 (35 %). LoCard -aineistossa pääryhmätasolla eniten ostettiin maitoa (117 l), toiseksi eniten maitovalmisteita (84 kg) ja kolmanneksi lihaa (59 kg). Maidoista kevytmaitoa ostettiin eniten (53 l) ja toiseksi eniten rasvatonta maitoa (46 l). Maitovalmisteista juustoa ostettiin eniten (29 kg), jogurttia toiseksi eniten (26 kg) ja piimää kolmanneksi eniten (9 l). Muu liha -ryhmään kuuluvia tuotteita ostettiin keskimäärin 26 kiloa. Lihalajeista siipikarjanlihaa ostettiin eniten (15 kg) ja toiseksi eniten sianlihaa (lähes 11 kg). Ostomäärät henkilöä kohden olivat keskimäärin 52 % pienemmät verrattuna kotitaloustason ostomääriin, kun kaikki kotitaloudet oli huomioitu, ja keskimäärin 31 % pienemmät, kun ainoastaan yhden hengen kotitaloudet oli huomioitu. Maitoa kulutettiin pääryhmistä eniten kaikissa aineistoissa. Lihan, kalan ja kananmunien kulutus oli suurinta ravintotaseessa, kun taas maidon ja maitovalmisteiden kulutus oli suurinta LoCard -aineistossa, kun kulutus LoCardissa oli laskettu kotitaloustasolla. Maitovalmisteita ja voita ostettiin ravintotaseeseen ja kulutustutkimukseen nähden runsaasti: jogurtin, viilin, hapatettujen kermavalmisteiden, muiden tuoretuotteiden sekä juuston ostot kotitaloustasolla olivat suurempia kuin kulutus ravintotaseessa, ja voin kulutus oli suurinta LoCard-aineistossa, riippumatta siitä oliko kulutus laskettu kotitaloustasolla vai henkilöä kohden. Kalaa ostettiin vähän LoCard -aineistossa muihin aineistoihin verrattuna. Elintarvikkeiden kulutuksen suhteelliset osuudet olivat kulutusmääriä johdonmukaisempia eri aineistojen välillä. Eniten eroa oli lihan kulutuksessa: taseessa sianlihan osuus lihan kokonaiskulutuksesta oli 41 %, kun taas kulutustutkimuksessa ja LoCardissa muu liha -ryhmään kuuluvien tuotteiden kulutus oli lähes puolet lihan kokonaiskulutuksesta. Johtopäätökset: Eläinperäisten elintarvikkeiden ostot olivat melko hyvin linjassa ravintotaseen ja kulutustutkimuksen tietojen kanssa huolimatta aineistojen metodologisista eroista, mikä tukee käsitystä ostoaineiston käyttökelpoisuudesta ravitsemuksen seurannassa. Automaattisesti kerätyllä ostodatalla on ainutlaatuiset vahvuudet ja heikkoudet verrattuna muihin ruoankäytön tutkimusmenetelmiin, joten se tarjoaa uudenlaisen näkökulman ruokailutottumusten tutkimiseen. Tarvitaan kuitenkin lisää tutkimusta myös muiden kuin eläinperäisten elintarvikkeiden kulutuksesta verrattuna ravintotaseeseen ja kulutustutkimukseen, jotta voidaan arvioida antavatko aineistot samansuuntaista tietoa kaikkien elintarvikeryhmien kulutuksesta. On myös syytä tutkia ostodatan olisi soveltuvuutta yksilötason ruoankäytön tutkimiseen, sillä datan haasteita on se, että ostoja kerätään sekä kotitalouden, että yksilön tasolla.
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(2020)The literature review deals with the status and the causes of bread waste all over the world. More importantly, the current managements of increasing bread waste. Enzymatic hydrolysis by α-amylase and amyloglucosidase is a potential treatment, which transforms bread waste into syrups for further revaluation with functional compounds. The aim of the experimental work was to determine the influence of enzymatic hydrolysis conditions (hydrolysis time, hydrolysis temperature, enzyme dosage of α-amylase and amyloglucosidase) on glucose content and free amino nitrogen (FAN) content of resulting hydrolysate from bread waste. Furthermore, the effect of lactic acid fermentation on glucose content was studied when bread waste was subjected to simultaneous hydrolysis and fermentation with Pediococcusclaussenii (E-032355T). Glucose content varied greatly under different hydrolysis conditions from nearly 17% to only 5%, while FAN content was barely influenced. pH value had slight changes and no Bacillus cereus bacteria was found. A well fitted model for glucose content was obtained with an excellent power of interpretation, prediction and optimization. Enzyme dosage was the principal factor having a significant effect on hydrolysis efficiency, followed by temperature and time. With optimized hydrolysis conditions (50 mg/kg α-amylase and 2500 mg/kg amyloglucosidase, 30℃, 19 hours), the glucose content 16.31% was achieved, and the result was in accordance with the value 16.39% predicted by the model. Moreover, a 2.2% increase of glucose yield was detected when waste bread was subjected to simultaneous hydrolysis and fermentation compared to the control sample (bread waste was treated only with hydrolysis under the same condition). The well growth of used lactic acid bacteria (LAB) strains Pediococcusclaussenii (E-032355T) resulted in lower pH, which further improved enzymes activities and increased glucose content of the hydrolysate.
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(2020)The agricultural management of soil organic carbon (SOC) is highly important to build a climate-smart and eco-friendly agricultural system. For this reason, our study was conducted to test the hypothesis that the effect of different treatments consisting of soil textures and crop varieties on SOC stock has a major influence on any loss or accumulation of SOC storage. We also test the hypothesis that equivalent soil mass (ESM) is more consistent than fixed depth (FD) in estimating SOC content. In our study, the results were not found statistically significant but they showed minor differences in the SOC estimation. The difference was not clearly observed between ESM and FD methods. The influence of soil textures and crop varieties on SOC content was not significantly different. However, the cultivation of grass in fine-textured soils slightly increased the SOC stock compared with that in coarse-textured soils probably due to enhanced grass root growth and aggregation in fine-textured soils that protects soil organic matter from microbial oxidation.
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(2020)Mikrolevät ovat yksisoluisia organismeja, jotka sisältävät lajista ja kasvatusolosuhteista riippuen proteiineja 25–63 % kuivapainosta, lipidejä 2–25 % kuivapainosta, hiilihydraatteja 35–57 % kuivapainosta ja kivennäisaineita 6–30 % kuivapainosta. Lipideistä 15–57 % on triasyyliglyseroleja ja 0,7–37 % poolisia lipidejä, kuten fosfo- ja glykolipidejä. Mikrolevien koostumusta sekä mikrolevien lipidien uuttoa on tutkittu aiemmin Helsingin yliopistossa, ja näissä tutkimuksissa on herännyt tarve lisätiedolle mikrolevien poolisista lipideistä. Tämän tutkimuksen tavoitteena oli luokitella mikrolevien sisältämät lipidit poolisuuden mukaan selvittäen osuudet rasvahappokoostumuksen perusteella. Lisäksi tavoitteena oli kehittää HPLC-menetelmä mikrolevien fosfo- ja glykolipidien määrittämiseen. Poolisten lipidien rasvahappojen määrityksessä mikroleväuutteiden lipidit erotettiin poolisuuden mukaan kiinteäfaasiuutolla ja uutteista määritettiin rasvahappopitoisuudet kaasukromatografisesti. HPLC-menetelmä kehitettiin tutkimalla poolisten lipidien profiileja nestekromatografia-valonsirontadetektorilla (LC-ELSD). Kehitetyllä LC-ELSD-menetelmällä tutkittiin Euglena gracilis ja Selenastrum sp. -mikrolevänäytteiden poolisia lipidiluokkia. Mikrolevänäytteissä esiintyvät fosfo- ja glykolipidit tunnistettiin nestekromatografia-massaspektrometrisesti (LC-MS). Tutkimuksen tuloksista selvisi, että Selenastrum sp. -mikrolevän kokonaislipidipitoisuus oli suurempi kuin E. gracilis -mikrolevän. Molemmilla lajeilla eniten rasvahappoja oli poolisissa lipideissä ja molempien lajien rasvahappokoostumukset vaihtelivat kasvatuserästä ja -olosuhteista riippuen. Kehitetyllä LC-ELSD-menetelmällä mikrolevänäytteiden poolisten lipidien profiileissa erotettiin monogalaktosyylidiasyyliglyseroli (MGDG) ja fosfolipidit luokkana. Tulosten perusteella MGDG vaikuttaisi olevan yleisin glykolipidi tutkituissa mikrolevänäytteissä ja fosfatidyylietanolamiini yleisin fosfolipidi. Glyko- ja fosfolipidiluokissa ei ollut eroa mikrolevälajien tai kasvatuserien välillä. Mikrolevien MGDG:t vaikuttivat sisältävän monityydyttymättömiä rasvahappoja ja fosfolipidit tyydyttyneitä tai kertatyydyttymättömiä rasvahappoja. Lisätutkimusta tarvitaan poolisten lipidien kvantitatiiviseen määrittämiseen ja menetelmän kehittämiseen fosfolipidien erottumisen osalta.
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