Browsing by Subject "ultrasuodatus"

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  • Roiniala, Tia (Helsingin yliopisto, 2018)
    Maisterintutkielman kirjallisuuskatsauksessa perehdyttiin härkäpavun ominaisuuksiin ja proteiinijauheiden valmistusmenetelmiin. Kokeellisen osion tavoitteena oli eristää härkäpapuproteiinia ja vertailla konsentrointimenetelmän vaikutusta sumutuskuivatun härkäpapuproteiini-isolaatin ominaisuuksiin ja proteiinin saantoon. Proteiini eristettiin härkäpapujauhosta veteen uuttamalla. Uuttoliuokset konsentroitiin kahdessa erässä, ultrasuodattamalla ja saostamalla, jonka jälkeen konsentroidut liuokset sumutuskuivattiin. Kuivatuista härkäpapuproteiinijauheista tutkittiin vesi- ja proteiinipitoisuudet, partikkelikoko, väri ja funktionaalisista ominaisuuksista proteiinien liukoisuus ja vaahdonmuodostuskyky. Lisäksi laskettiin proteiinisaanto prosessin eri vaiheissa. Ultrasuodatetun härkäpapuproteiinijauheen proteiinipitoisuudeksi saatiin 82 % (märkäpaino), kun taas saostetun proteiinijauheen proteiinipitoisuus oli 94 %. Vesipitoisuudet samassa järjestyksessä 5 % ja 7 %. Ultrasuodattamalla konsentroitu jauhe oli väriltään vaaleampaa ja keltaisempaa kuin saostamalla konsentroitu. Partikkelikooissa ei havaittu tilastollisesti merkitseviä eroja. Proteiinit liukenivat heikosti isoelektrisen pisteen alueella (pH 4–5). Saostettu härkäpapuproteiini-isolaatti liukeni ultrasuodatettua isolaattia paremmin happamassa pH:ssa. Emäksisessä pH:ssa liukoisuus erot tasoittuivat. Ultrasuodatettu härkäpapuproteiini-isolaatti muodosti tehokkaammin ja pysyvämpiä vaahtoja kuin saostettu isolaatti tai härkäpapujauho. Koko prosessin proteiinisaanto jäi matalaksi. Ultrasuodatetulla erällä alkuperäisestä proteiinista saatiin talteen 19,8 %, kun saostetulla saanto jäi 6,7 %:iin. Tulosten perusteella proteiinin eristys onnistui hyvin ja saatiin aikaan härkäpapuproteiini-isolaatteja, proteiinipitoisuuksien noustessa yli 80 %:iin. Konsentroinnilla voidaan vaikuttaa isolaatin proteiini- ja vesipitoisuuteen, väriin ja funktionaalisiin ominaisuuksiin. Menetelmän valintaan vaikuttaa proteiini-isolaatin käyttökohde ja sen vaatimat ominaisuudet. Konsentrointi- ja kuivausmenetelmät vaativat kuitenkin edelleen optimointia, jotta proteiinin saantoa saataisiin nostettua.
  • Veskimäe, Hele-Mai (Helsingin yliopisto, 2017)
    Jogurtin valmistuksessa ultrasuodatus (UF) on mahdollinen vaihtoehto maitojauhe- tai maitoproteiinilisäykselle. Tutkielman kirjallisuusosiossa perehdyttiin maidon ultrasuodatusprosessiin ja jogurtin proteiinipitoisuuden nostamisen eri vaihtoehtoihin. Kokeellisessa tutkimuksessa pyrittiin selvittämään, voidaanko jogurtin proteiinipitoisuutta säädellä hallitusti hyödyntämällä valmistuksessa ultrasuodatettua maitoa. Kiinnostuksen kohteena oli se, että aiheuttaako maitoproteiinijauheen korvaaminen ultrasuodatetulla maidolla muutoksia jogurtin laadussa. Kokeellisen tutkimuksen aikana valmistettiin rasvattoman maidon ultrasuodatuksella saaduista retentaatista ja permeaatista rasvatonta ja 2 % rasvaa sisältäviä sekoitejogurtteja. Jogurtit valmistettiin eri proteiinipitoisuuksilla niin, että ne vastasivat konsentraatiokertoimia 0,9, 1,1, 1,2, 1,4 ja 1,6. Näiden lisäksi valmistettiin vertailutuote, jossa tarvittava maitoproteiinipitoisuus saavutettiin lisäämällä rasvatonta maitoproteiinijauheetta. Jogurttimaidot fermentoitiin kolmen kaupallisen hapatteen, A1, A2 ja A3, avulla. Näytteet valmistettiin kahtena tutkimussarjana. Ensimmäisessä sarjassa jogurtit valmistettiin kolmella eri proteiinipitoisuudella (konsentraatiokertoimilla 1,1, 1,2, 1,4) ja toisessa sarjaan lisättiin 0,9 sekä 1,6 konsentraatiokertoimet. Valmistetuista jogurteista mitattiin synereesi, pH-arvo ja konsistenssi vuorokauden, 1 viikon ja 2 viikon kylmäsäilytyksen (6 °C) aikana. Näytteitä seurattiin myös aistinvaraisesti ja toiseen tutkimusvaiheeseen sisältyi tuotteiden fermentointiaikainen pH-arvon seuranta. Maitoproteiinijauhelisäyksellä valmistettu ja samalla proteiinipitoisuudella ultrasuodatuksen jakeista valmistettu jogurtti eivät eronneet merkittävästi aistinvaraisessa arvostelussa. Jogurttimassojen laktoosipitoisuudessa ennen fermentointia esiintyi eroja niin, että maitojauhelisäyksellä valmistetussa jogurttimaidossa oli enemmän laktoosia kuin jakeista valmistetuissa jogurttimassoissa. Niin rasvattomien kuin 2 % rasvaa sisältävien jogurttinäytteiden kohdalla nopeiten fermentoitui kaikilla kolmella hapatteella maitojauhelisäyksellä valmistettu massa. Korkeammalla proteiinipitoisuudella olevat massat (konsentraatiokertoimilla 1,4 ja 1,6) saavuttivat tavoite pH-arvon 5 ja 5,5 tunnissa. Kylmävarastoinnin aikaisen heran erottumisen mittauksista havaittiin, että niin rasvattoman kuin 2 % rasvaa sisältävän jogurttimassan 4 (konsentraatiokerroin 1,4) heran erottuminen oli pienintä verrattuna muihin massoihin kaikilla kolmella hapatteella valmistetuissa jogurteissa. Sama massa erottui myös jogurttien konsistenssimittauksissa.
  • Laakso, Kristian (Helsingin yliopisto, 2018)
    Palautusjuoma on harjoittelun jälkeen nautittava nestemäinen elintarvike. Sille ei ole virallista määritelmää, mutta sen tarkoituksena on sisältää tärkeitä ravintoaineita kuten aminohappoja ja hiilihydraatteja, jotka käynnistävät urheilusuorituksesta palautumisen. Palautusjuomat voidaan jakaa karkeasti juomajauheisiin ja valmiisiin juotaviin tuotteisiin. Kasvipohjaisen palautusjuoman pohjana voisi toimia kasviproteiiniuute. Tämän työn tarkoituksena oli tutkia erilaisten uutto-olosuhteiden vaikutusta kvinoaproteiinien uuttumiseen. Uute, jossa olisi korkein proteiinisaanto, voisi toimia teoreettisen palautusjuoman pohjana. Muuttujina käytettiin liuotin/siemen (w/w) -suhdetta (10:1 ja 20:1), liuotinta (pH 6,71 ja 9; NaCl-pitoisuus [0 mol/l ja 0,03 mol/l]) ja liuottimen lämpötilaa (25 °C ja 40 °C). Uuttoaika oli kaikissa näytteissä 30 min. Proteiinisaantoon tilastollisesti merkitsevästi vaikuttavat muuttujat (p < 0,05) olivat liuottimen pH ja lämpötila. Tämän tiedon perusteella uutetta valmistettiin lisää kahdeksan litraa, jonka muuttujien arvoina olivat pH 9, NaCl-pitoisuus 0 mol/l, 40 °C liuotin/jauho (w/w) -suhde 10:1. Uute ultrasuodatettiin 20 kDa:n cut off -arvon kalvolla ja suodatuksesta otettiin talteen retentaatti ja permeaatti. Retentaattia sumutuskuivattiin 984 g ja kuiva-ainesaanto oli 0,84 %, eli 8,2 g jauhetta. Proteiinisaanto oli 29,8 %. Sumutuskuivauksesta saadusta jauheesta määritettiin proteiinipitoisuus, kuiva-ainepitoisuus ja vaahtoavuusominaisuuksia. Pakkaskuivatusta retentaatista tehtiin viskositeetti ja saponiinipitoisuusmääritykset. Lisäksi pakkaskuivatusta retentaatista ja permeaatista tehtiin SDS-PAGE elektroforeesi, jotta nähtäisiin, miten proteiinit jakautuivat ultrasuodatuksessa permeaattiin ja retentaattiin. Sumutuskuivatun kvinoajauheen proteiinipitoisuus oli 39,1 %. SDS-PAGE -määrityksestä saadun proteiiniprofiilin perusteella proteiinit jäivät retentaattiin ja ultrasuodatus onnistui hyvin. Retentaatti sisälsi kvinoalle ominaisia proteiineja: globuliineja (55 kDa) ja chenopodiineja (31–33 kDa). Tämän tutkimuksen perusteella työssä käytetyistä hiotuista kvinoan siemenistä uuttui vain vähän proteiineja, mikä johti matalaan proteiinipitoisuuteen sekä uutteessa että jauheessa. Siemenet eivät soveltuneet matalan proteiinipitoisuuden vuoksi palautusjuoman raaka-aineeksi, mutta vaahdonmuodostusominaisuuksien perusteella kvinoa kuitenkin vaikuttaa lupaavalta raaka-aineelta elintarviketeollisuuteen, erityisesti leipomoteollisuuteen. Raaka-aine vaatii kuitenkin lisätutkimusta, ja tulevaisuudessa määrityksiä voisi mahdollisesti tehdä hiomattomista siemenistä, jolloin proteiinipitoisuus olisi lähtökohtaisesti korkeampi.
  • Bergdahl, Isa (Helsingin yliopisto, 2021)
    Apples are one of the most eaten and processed fruits in the world. For example, in apple juice production, proportion of the main side stream, apple pomace is 25–35%. It contains mainly carbohydrates and little bit of protein and fat, which makes it unsuitable for feed purposes. Nevertheless, carbohydrates are commonly extracted by water extraction for further purposes of use. Membrane separation is an interesting possibility to fractionate molecules of different sizes from aqueous solutions, for example with ultrafiltration (UF) lactose is separated from whey in dairy industry. Advantages of membrane separation include low energy consumption, low environmental impacts and no phase change. Main limitation for the use of membrane separation process is fouling of membranes, which means that there is a decrease in permeation as a function of time. Aims of the study were to 1) optimize parameters for the membrane separation method by using model solutions in order to get good yield from the process and to 2) separate carbohydrates from apple pomace using water extraction and membrane separation method. Model solutions were used for determining of UF functionality. Sucrose model solutions (SMS) had three different concentration 1, 6 and 11% and pectin-sucrose model solutions (PSMS) had the same concentrations with a pectin addition of 0.5%. These were used to optimize transmembrane pressure (TMP) and concentration for apple pomace extract runs. Apple pomace originated from mixed variety of Finnish apples. Apple pomace was stored in freezer until needed. It was first homogenized by a colloid mill, and carbohydrates were extracted with water extraction in three different apple pomace to water ratios (w/w) with constant extraction time and temperature (80 min/30 ˚C). Three parallel extractions and UF runs were performed for each of the ratios (1:30, 1:10, 1:2 double extraction). Based on the results of the UF runs of model solutions TMP of 4.5 bar was applied for these runs. Samples were taken from original feed solution (weighed solution without the water from the equipment), running solution (after 5 min relaxation time, includes the water from the equipment), permeate and retentate, and from these sugars were analysed with UPLC, dry matter was determined by freeze drying and flux and fouling were calculated. Lower concentration and higher pressure resulted in higher flux (L m-2 h-1) in UF. Presence of bigger compounds, such as pectins, slowed down the experiment and thus, flux. Apple pomace extract runs followed the same principal of higher concentration leading into slower process. The yield of water extraction from dry matter in apple pomace varied between 35 to 65%, the highest yield originated from the pomace to water ratio of 1:30 (w/w). Sugar analysis showed that the permeate from apple pomace extracts contained mostly fructose (average in all of the nine runs 57.4% ± 1.8), sucrose (21.8% ± 3.9) and a little bit of glucose (13.3% ± 1.2) and malic acid (7.4% ± 2.2). In summary, combination of efficient homogenization of raw material by a colloid mill, conventional water extraction and UF of water extract proved to be successful for carbohydrate extraction from apple pomace. Modelling concluded that lower concentration and/or higher pressure leads into higher flux in the process. The whole UF process is slower if there is pectin in the feed solution.
  • Horsma-Heikkinen, Jenni (Helsingin yliopisto, 2020)
    The antibiotic resistance of pathogenic bacteria is becoming a major problem in treating bacterial infections and development of new antibiotics is very challenging. In traditional phage therapy the bacteriophages, viruses that infect bacteria, are being used as an optional treatment to eliminate infectious agents. Methicillin resistant Staphylococcus aureus (MRSA) is resistant to several currently used antibiotics and is one of the most common antibiotic resistant bacteria causing infections. Therefore, it is a potential target for the phage therapy. Some of the Staphylococcus aureus strains produce several different enzymes and toxins which can be harmful to patients. Products developed for phage therapy purposes need be free from the material originated from host bacteria. In this study, three different methods were tested for the purification of bacteriophages infecting S. aureus. The main goal was to produce phage lysates with purity and phage concentration suitable for therapeutic purposes using a fast and aseptic procedure upgradable for large volumes. The tested methods were ultrafiltration with filter tubes from two different manufacturers (Sartorius Vivaspin 6 ja Merck Millipore Amicon Ultra 4), polyethylene glycol (PEG) precipitation and ion exchange chromatography. Three different bacteriophage strains were used. One was isolated from a commercial Russian phage therapy product (vB_SauM_fRuSau02) and the other two from feces of pigs (vB_SauS_fPf-Sau02 and vB_SauS_fPfSau03). Host bacteria strains for the first bacteriophage were S. aureus strains TB4 and 13KP originally isolated from human infections. Two host strains for the latter two phages were MRSA strains isolated from healthy pigs. Purification of the phage lysates was evaluated by measurement of enterotoxins produced by S. aureus bacteria, measurement of free double stranded DNA (dsDNA), and by cytotoxicity test in cell cultures. All evaluation methods were commercially available tests. To determine how much of the bacteriophages were lost in the process, the phage concentrations of the lysates were determined before and after the purification and recovery rates were calculated for the viruses. After two separate ultrafiltrations, the recovery rates of the bacteriophages were mainly good, but there was a lot of variation in the results. The lowest recovery rate calculated was 5%, the highest 57%, and the mean of all the rates 24%. In this study the ion exchange chromatography was combined with ultrafiltration which was used in pre-cleaning of the lysates and changing the phages in a buffer suitable for the chromatography. The recovery rates from the ion exchange chromatography varied between 14-26% but the results may be affected by the ultrafiltration steps performed before and after, since a lot of variation was seen in ultrafiltration processes. PEG precipitation was performed for one phage lysate only in order to compare the laboriousness of the method and the rates of the recovery to the other methods used. The rate of recovery from the PEG precipitation was 9,5% which was fairly low. The purity of this lysate was not evaluated since the method was estimated to be too laborious compared to the other methods. Ultrafiltration turned out to be an efficient method in the removal of small protein molecules, such as enterotoxins from bacteriophage lysates. With two sequential ultrafiltrations 96-99% of the enterotoxins in the lysates were removed. The removal of the free dsDNA was also successful but there was variation between the phage lysates. Approximately 67-93% of the free dsDNA was removed but it is possible that some of the measured DNA originated from lysed bacteriophages as their genome also consists of dsDNA. Ion exchange chromatography produced extremely well purified phage products. The fractions had no enterotoxins left or the amount was below the detection limit of the test (<0,5-1 ng/g). Ion exchange chromatography was able to remove 96-99% of the free dsDNA of the lysates. It is possible that some of the DNA left in the lysates originated from the bacteriophages lysed during the process or in storage after that. When comparing how simple and fast the methods were, the ultrafiltration turned out to be superior. It can be used in fast production of bacteriophage products for the treatment of S. aureus infections. The purification achieved with the ultrafiltration should be adequate for a topical use of the product. When higher purity products are required, e.g. for administrating the product intravenously, ion exchange chromatography might be a safer option.
  • Uotila, Sarri (Helsingfors universitet, 2013)
    Haemoglobin and globin from blood cells and albumin, fibrinogen and immunoglobulins from blood plasma are the most important proteins in slaughter blood. Different fractions of blood have slightly different technological properties. Adding blood proteins can have an effect on the gelling, foaming and emulsifying properties of foodstuffs. Blood protein hydrolysates have antioxidative and antigenotoxic effects that could be utilised as food preservatives or in functional foods to strengthen health. The nutritional value of food can be improved by adding blood proteins. Blood proteins can be utilized by replacing egg, fat and sodium caseinate in foods, to improve structure and shelf life of food. Blood proteins can also be utilised replacing egg white, milk or soy proteins or replacing fat in light products. Ultrafiltration is a common method in the food industry and it is also suitable for processing blood proteins. The aim of the study was to optimize an ultrafiltration method to concentrate porcine slaughter blood for use in the food industry and to determine the technological properties of plasma concentrate and its suitability for use in the food industry. Response surface methodology was used to create a mathematical model to calculate the optimal ultrafiltration parameters for plasma concentrations. Optimal conditions for the ultrafiltration were an Ultracel PLTK 30 membrane, temperature of 40 ºC and pressure of 2 bar. The technological properties of blood proteins were measured at pH 4.5, 5.5, 6.3 and 7.0. Volume and stability were measured from foams prepared by whipping from plasma concentrate diluted to protein concentration of 5.8 %. Foam volume and stability were greatest at pH 5.5 and weakest at pH 7.0. Emulsifying capacity was measured from plasma concentrate diluted to 0.01 % protein concentration. Emulsifying capacity was weakest at pH 5.5 and increased towards high and low pH. Rheological properties of gels made from 10 % plasma concentrate were measured. The gels were weakest near the isoelectric point of plasma proteins at pH 5.5. Plasma concentrate was used to prepare bologna sausage. The structure and sensory properties of the sausages were evaluated. The sausages containing plasma concentrate were evaluated as equal to control sausages in every category.
  • Karttunen, Kaisa (Helsingfors universitet, 2016)
    Cheese-making is one of the largest areas of milk processing. Due to large quantities of cheese produced, the decline in milk production and the tightening of environmental legislation, more efficient dairy processes are being developed with the target of full utilization of the raw material. For these reasons, solutions based on membrane technology are becoming more common in the dairy industry. Moreover, membrane techniques allow rationalization of the existing processes and the manufacturing of entirely new products. The purpose of this study is to examine the possibilities of using ultrafiltration in the production of spreadable cream cheese based on scientific articles and studies and by performing pilot-scale experimental research. Under this study, spreadable cream cheese was produced from standardized, fat-containing quark. The whey was separated by ultrafiltration instead of the traditional centrifugation method. A co-company’s pilot-scale membrane filtration equipment was used to produce both light cream cheeses and normal-fat cheeses. The quality characteristics of these samples were compared to a commercial product with chemical analyses and various structural measurements. In addition, the sensory properties of all the samples were evaluated by a consumer test. In this study, differences were observed between the pilot-samples and the reference samples, in both the light cream cheeses and the normal-fat cheeses. The most obvious differences were found in the results of structural measurements. These differences are likely to be explained by chemical composition of the samples, in particular in regard to the fat content. In the consumer test, the reference samples were also estimated to differ from the pilot-samples by several quality characteristics. All in all, this study gives significant information for the co-company’s new process method. Based on the results of this research the co-company was able to move on to industrial-scale test runs.