Browsing by master's degree program "Elintarviketieteiden maisteriohjelma"

Oat beta-glucan, β-glucan, is a soluble dietary fibre located in the endosperm and aleurone cell walls. It is a polysaccharide that has an ability to form viscous gel in aqueous solutions due to its high water binding capacity. The objective of this study was to determine the physical characteristics of commercial oat β-glucan with different purity in solution. Four commercial oat beta-glucan powders with varying β-glucan content were provided for this study. Solubility, water binding capacity, viscosity, suspension and emulsion stability, droplet particle size, particle distribution and zeta potential were determined from the samples. There were two phases in the experimentation part in which the first phase focused on suspensions and the second phase focused on emulsions. There were four different homogenising treatments used to solubilize the samples into water during the first phase of the experiment, which were stirring in room temperature, 80 ˚C, Ultra-Turrax and microfluidization. Megazyme exhibited highest solubility in water with a solubility rate of 100 % regardless of the treatment used. OatWell had the highest water binding capacity (11.7 g/g) after heat treatment. Heat treated OatWell had the highest viscosity (590 mPas). Megazyme emulsions had the highest emulsion stability (TSI ranging from 0.6 to 3.6) as it did not experience phase separation until fifth day of measurement. Megazyme emulsions also had the lowest particle sizes ranging from 0.4 μm to 1.5 μm. The results of this study highlight that the content of β-glucan has notable effect on its solubility and the homogenisation treatment used has an increasing effect on solubility and decreasing effect on water binding capacity and viscosity. Purity of the oat β-glucan also has an effect on emulsion stability as high purity oat β-glucan are able to stabilise emulsion system after homogenisation.

Oil migration in the fat fillings causes deterioration of food quality and changes in product properties. The fats used in fillings should be compatible with the fats in the product. Vegetable oils cannot be added directly to the fillings. Fillings need to be modified. Plant materials could bind oil in the products. It is not clear how a filling made from edible plant material and vegetable oil affects the shelf life of product. The aim of this study was to investigate how different edible plant materials bind oil and how vegetable oil migrates in the product during three months of storage. The oil absorption capacity of plant materials was determined by a centrifugation method. The filling was made of selected edible plant materials and vegetable oil. Prepared filling was used in the test product. The test product was stored at two different storage temperatures: 20 and 23 °C. The migration of oil in product was examined by determining the fatty acid composition of the test product by gas chromatography, the melting point by differential scanning calorimetry (DSC), the fat blooming by a DigiEye device and the sensory properties by sensory evaluation. There were big differences in the oil absorption capacity of the different edible plant materials. During storage, the major changes in product fatty acid compositions occurred in the control samples without plant material. Oil migration occurred in all the vegetable oil-based samples. The indicator fatty acids of oil migration, migrated to the test product more in vegetable oil-based samples than in the samples containing different fat. However, the edible plant materials bound the oil in the test product and slowed down the migration of oil. According to the DSC measurement, the fat of all the samples remained in the desired crystalline form. The migration of the oil had not progressed so far that the crystal form would have changed. Based on the DigiEye measurement, none of samples bloomed. However, by sensory evaluation, blooming had already occurred. The elevated storage temperature also accelerated the fat blooming of vegetable oil-based samples. Thus, in vegetable oil-based test product, the blooming due to oil migration had already begun. Research could be continued by further developing the filling as well as the shape of the samples. The storage time could also be extended to make the changes clearer.

Tutkimuksen tavoite oli korvata täysmajoneesin ja täysmajoneesipohjaisen katkarapusalaatin etikka- ja sitruunahappo osin muilla orgaanisilla hapoilla ja selvittää muutosten vaikutusta kyseisten majoneesituotteiden aistinvaraisiin ominaisuuksiin ja säilyvyyteen. Tutkimuksessa käytettiin maito-, omena- ja viinihappoa. Kokonaishappomäärästä 2-10 % korvattiin näillä hapoilla tai niiden yhdistelmillä. Näytteitä oli yhteensä 24. Tutkimus koostui aistinvaraisesta arvioinnista ja säilyvyyskokeesta. Aistinvarainen arviointi tehtiin kuvailevalla poikkeama vertailunäytteestä -menetelmällä. Menetelmässä näytteitä verrattiin tuotteiden markkinoilla oleviin versioihin. Koulutetussa raadissa oli seitsemän arvioijaa. Säilyvyyskoe koostui mikrobiologisesta analyysistä ja pH-mittauksista. Mikrobiologisessa analyysissä määritettiin aerobiset bakteerit, hiivat ja homeet. Katkarapusalaattien erot vertailunäytteeseen olivat useammin tilastollisesti merkitseviä kuin täysmajoneesien. Maitohappo käytettynä omena- ja viinihapon kanssa lisäsi katkarapusalaatin maun raikkautta. Maitohappo myös lievensi omena- ja viinihapon voimakasta makua. Täysmajoneesissa maitohappo lisäsi kuitenkin suutuntuma rasvaisuutta. Siten se voi sopia paremmin kevytmajoneeseihin kuin täysrasvaisiin versioihin. Omena- ja viinihappo lisäsivät katkarapusalaatissa maun suolaisuutta, happamuutta ja raikkautta sekä jälkimaun kokonaisvoimakkuutta. Korrelaatioiden perusteella maun raikkaus kasvoi maun happamuuden ja suolaisuuden sekä jälkimaun kokonaisvoimakkuuden kasvaessa. Koska omena- ja viinihappo lisäsivät merkittävästi maun suolaisuutta, niitä voidaan mahdollisesti hyödyntää vähäsuolaisissa majoneesisalaateissa. Omena- ja viinihappo myös korostivat tillin ja sipulin makua katkarapusalaatissa. Muutokset täysmajoneesin ja katkarapusalaatin happokoostumuksissa eivät vaikuttaneet niiden säilyvyyteen. Tuotteiden viimeisinä käyttöpäivinä hiivojen, homeiden ja aerobisten bakteerien kokonaismäärät eivät ylittäneet sallittuja rajoja. Täysmajoneesinäytteiden pH-arvojen todettiin nousevan hieman varastoinnin aikana. Samaa ei havaittu katkarapusalaattinäytteissä. Tutkimuksesta voidaan päätellä, että pienillä orgaanisten happojen muutoksilla voidaan säätää majoneesituotteiden aistinvaraisia ominaisuuksia ilman että säilyvyydessä tapahtuu muutoksia.

Vähittäiskaupoissa pyritään tarkalla suunnittelulla ja ennustamisella ehkäisemään elintarviketuotteiden myymättä jäämistä. Kokonaan siltä ei voida kuitenkaan välttyä, sillä kuluttajien ostokäyttäytyminen voi aiheuttaa odottamatonta myynnin vaihtelua. Elintarvikkeen päiväyksen umpeutumisen jälkeen tulee se hyödyntää muilla tavoin kaupan ruokahävikin ehkäisemiseksi. Ensisijaisten hävikinhallintakeinojen ohella kaupat hyödyntävät elintarvikkeissa päiväysalennuksia, joiden tarkoitus on alennetulla hinnalla saada kuluttajia valitsemaan lyhyemmän päiväyksen tuotteita. Säästämismahdollisuuden lisäksi kuluttaja voi päiväysalennettuja elintarvikkeita valitsemalla omalta osaltaan vähentää kaupan ruokahävikkiä. Tässä tutkimuksessa oli tavoitteena selvittää, millainen merkitys päiväysalennetuilla elintarvikkeilla on kuluttajille, millaiset kuluttajat niitä suosivat ostoksissaan ja tulevatko ostetut päiväysalennetut tuotteet missä määrin käytettyä kotitalouksissa. Aineisto kerättiin verkkokyselyn avulla, ja kysely koostui pääosin monivalintakysymyksistä, jotka pohjautuivat aikaisempaan tutkimustietoon ja kirjallisuuteen. Vastaajia saatiin 444, ja heistä suurin osa oli naisia. Tulosten mukaan ostotodennäköisyydet kolmen esimerkkielintarvikkeen päiväysalennetulle vaihtoehdolle olivat keskimääräisesti korkeat, ja siten todettiin, että päiväysalennukset kiinnostavat kuluttajia tällä hetkellä paljon. Etenkin nuoremmat ja pienituloisemmat kuluttajat valitsivat muita todennäköisemmin päiväysalennetun vaihtoehdon. Merkittävänä motivaationa valinnassa on mahdollisuus säästää niiden avulla, mutta tuotteiden laadusta tai tuoreudesta ei haluta silti tinkiä liikaa. Hävikin vähentäminen päiväysalennusten avulla on merkittävyydeltään vähäisempi. Vaikka tuotteita valitessaan kuluttajat pohtivat niiden käyttömahdollisuuksia, joutuu päiväysalennettuina ostettuja tuotteita myös kotitalouksissa välillä roskiin. Jatkotutkimuksessa aihetta tulisi tutkia verraten Suomen laajuisesti eri alueita ja erilaisia alennustapoja, kuten eri alennusprosentteja, jotta voitaisiin saada kattavampia tuloksia. Kvalitatiivinen tutkimus antaisi enemmän ymmärrystä kuluttajien käyttäytymiseen päiväysalennettuja elintarvikkeita kohtaan niin kaupassa kuin kotitaloudessa.

Elintarviketeollisuuden kiinnostus palkokasvituotteisiin on kasvanut, sillä palkokasveja lisäämällä voidaan parantaa aterioiden toiminnallisia ominaisuuksia. Palkokasvien lipidipitoisuudessa ja rasvahappokoostumuksessa on vaihtelua mm. lajin, lajikkeen ja kasvuolosuhteiden mukaan. Palkokasveilla on tyypillisesti hyvä rasvahappokoostumus, ja ne sisältävät paljon tyydyttymättömiä rasvahappoja. Tutkimusten mukaan herneiden lipidipitoisuus on 0,4–3,7 %, härkäpavun 0,6–3,9 % ja lupiinin 4,5–15 %. Lipidit vaikuttavat elintarvikkeiden laatuun, ja niillä on tärkeä rooli tuotteiden rakenteelle, flavorille ja ravitsemuksellisille ominaisuuksille. Tämän tutkimuksen tavoitteena oli selvittää herne-, härkäpapu- ja lupiinivalmisteiden (jauhot, konsentraatit, isolaatit) kokonaisrasvapitoisuus ja rasvahappokoostumus. Palkokasvivalmisteiden lipidit fraktioitiin poolisuuden mukaan ja karakterisoitiin erityisesti poolisten lipidien fraktioita. Lisäksi tavoitteena oli selvittää palkokasvivalmisteiden sisältämiä fosfo- ja glykolipideitä. Tutkimuksessa lipidien uuttamiseen käytettiin paineistettua nesteuuttoa. Lipidien erottamiseen poolisuudelta eroaviin fraktioihin (4 fraktioita) käytettiin kiinteäfaasiuuttoa. Kokonaisuutteiden ja fraktioiden rasvapitoisuus ja rasvahappokoostumus analysoitiin kaasukromatografisesti. Poolisten lipidien profiileja tutkittiin korkean erotuskyvyn nestekromatografialla käyttäen valonsirontadetektoria (HPLC-ELSD). Palkokasvivalmisteissa esiintyvien fosfo- ja glykolipidien tunnistamiseen käytettiin standardeja ja nestekromatografia-massaspektrometri (LC-MS) -analyysin tuloksia. Tutkimuksen tuloksista selvisi, että herne-, härkäpapu- ja lupiinivalmisteista proteiini-isolaateilla ja -konsentraateilla oli suuremmat kokonaisrasvapitoisuudet kuin muissa valmisteissa. Lipidit vaikuttavat kulkeutuvan proteiinien mukana proteiinivalmisteisiin. Herne-, härkäpapu- ja lupiinivalmisteissa yleisimpiä rasvahappoja olivat linolihappo, öljyhappo, palmitiinihappo ja -linoleenihappo. Näytteiden rasvahappokoostumus oli samankaltainen, paitsi hernevalmisteissa oli muita enemmän -linoleenihappoa. Näytteiden välillä oli eroavaisuuksia lipidien jakaantumisessa fraktioiden välillä. Yleensä fraktio 1 sisälsi selkeästi eniten lipidejä ja lipidien pitoisuus oli pienin fraktiossa 3. HPLC-ELSD-analyysin perusteella näytteiden fraktioissa 1 ja 2 oli poolittomia lipidejä, mutta ne eivät erottuneet selkeästi. Fraktiossa 3 oli lähinnä galaktolipidejä ja fraktiossa 4 fosfolipidejä.

In 2020, 377 million liters of beer were sold in Finland. A large part of it was sold in multipacks for example in 12 or 24 multipacks. These multipacks require a secondary package which are often made out of shrink plastic or corrugated board. The aim of this study is to determine which of these materials is better alternative as packaging material in terms of functional properties as well as from an environmental point of view. The hypothesis is that corrugated board is more environmentally friendly option because it is made of renewable and recyclable material and the image of corrugated board is more environmentally friendly than shrink plastic. The properties required of the secondary packaging material were elucidated for the interview study, interviewing the different stages of the secondary packaging value chain. In general, the packaging was expected to be as environmentally friendly as possible and corrugated board was chosen by each interviewee as more environmentally friendly packaging material compared to shrink plastic. The functional properties of corrugated board were also highlighted more than properties of shrink plastic. The differences in the life cycle assessment of the materials in the secondary packaging were investigated as accurately as possible. Differences arise, for example, from the energy consumption of the packaging device, the logistics of the material and its disposal or possible recycling. Less shrink plastic is needed compared to corrugated board but the shrink plastic packaging machine consumes significantly more energy than the corrugated packaging machine. As the corrugated packaging machine is also faster the amount of energy used for packaging increases greatly with shrink plastic. Recycling both materials lower their carbon footprint and recycling is possible across the country. Both materials have their own strengths but the environmentally friendly image of corrugated board, its functional properties and the low energy used in packaging compared to shrink plastic seems to make corrugated board a very good alternative as a secondary packaging material.

The aims of the thesis included firstly to develop a process to prepare an oat-based milk substitute (OBMS) model in laboratory conditions representing industrial scale processing. After that, the quality of the oat-based milk substitutes prepared using the developed model was assessed and related with differences in the compositions of oats. The hypothesis was that the oat samples differ in terms of their behaviour during milk substitute manufacturing as well as final quality characteristics of the milk substitute. The OBMS process included mixing of oat flour with water, homogenisation and enzymatic hydrolysis of starch with α-amylase followed by enzyme inactivation, salt addition, pH-adjustment and removal of insoluble particles. Calcium phosphate and oil were added to the liquid milk phase after which a second homogenisation step and a final heat treatment were performed. The final OBMS was characterised in terms of mass yield, protein and dry matter contents, reducing sugars, particle size, viscosity, colloidal stability and colour. A functional OBMS process was developed and predictably, the oat samples behaved differently in the OBMS process. Mass yield of the OBMS increased as the starch content of the oat groat increased. High ash content of the oat groat correlated well a high protein content in the final OBMS. Viscosity and redness of the final product predicted well the milk yield and furthermore, it was noted that the higher the viscosity of the OBMS was, the slower it sedimented. This work provides relevant information on the oat composition that is suitable for oat-based milk substitutes.

The seeds of faba bean (Vicia faba L.) contain volatile and non-volatile off-flavour compounds which are perceived as beany flavour, bitter taste, or astringent sensation, and which can impair the acceptability and liking of faba bean. The aim of this study was to investigate how hydrocolloids added to faba bean protein concentrate (FPC) affect its bitterness. The hypothesis was that the bitterness of FPC was significantly suppressed by the added hydrocolloids. A sensory evaluation study was conducted for six slurry samples that contained 25 % (w/w) FPC in water and of which five samples contained also one of the following ingredients selected based on preliminary tests: carboxymethyl cellulose, wheat starch, guar gum, NaCl, or sucrose. A trained panel (n = 10) assessed the bitterness and thickness of the samples on a line scale (from 0 = “not at all bitter/thick” to 10 = “very bitter/thick”) in three independent sessions. Additionally, the viscosities and pH of the samples were measured to study the possible changes that occurred during storage of the samples. Only a slight difference was found in the bitterness of the samples. The wheat starch sample was assessed as the least bitter and the thickest in mouth, and it was also the most viscous sample. However, these results need to be looked at critically as the viscosities of the samples decreased during the three-day storage, and as the panelists did not agree on the bitterness ratings of the samples. Hence, further research is needed to better understand the significance of hydrocolloids in masking the bitterness of faba bean.

Bacteria coordinate the virulence factor production and biofilm formation by activating the mechanism of intercellular communication called quorum sensing (QS). The biofilm matrix protects bacteria against variety of stress conditions, including e.g., effects of antibiotics and disinfectants. QS inhibitors (QSI) are molecules that can inhibit the QS mechanism. QQ is a QSI inhibitor that interrupts the cell-to-cell signaling already outside of the bacterial cell. Dairy propionic acid bacteria have known antimicrobial properties but their ability to produce anti-QS compounds have not yet been studied. Previous studies have shown positive results of the anti-QS activity exerted by lactobacilli, but more research is needed to uncover mechanistic details behind their QS-inhibitory effects. The aim of this study was to investigate the anti-QS and QQ activity of propionic bacteria and lactobacilli. The used method was an in-house optimized screening method based on using wild-type and mutant strains of Chromobacterium violaceum. This bioreporter produces a QS-mediated, measurable color pigment. Here, the limit of potential QSI and QQ inhibition was set to 50 % inhibition. Viability of bioreporter was analyzed by resazurin staining. Propionibacterium freudenreichii strains demonstrated both the QSI (64–71%) and QQ (52–60%) activities against the tested C. violaceum reporters. In the case of lactobacilli, Lacticaseibacillus rhamnosus GG, Limosilactobacillus mucosae 2674, Lactobacillus acidophilus 80, Lactobacillus curvatus 453 and Lactobacillus kefiri 3070 inhibited the QS-activation of the wild-type bioreporter strain by 45 to 90 %. There was a great variability in the anti-QS screening assays involving the mutant strain, which may be explained by the possible sensitivity of the compounds to the analysis conditions used or more sensitive response of the mutant strain to the tested agents. In conclusion, the obtained results show that L. acidophilus 80 produced bactericidal compounds. L. reuteri 410 did not have any effect on the QS-indicator production in wild-type bioreporter but was able to inhibit QS-induction in the mutant reporter by 72% (QQ activity). This study showed that P. freudenreichii strains as well as certain lactobacilli have an ability to produce QSI and QQ activity against some gram-negative biofilm pathogens. Pathogens have different QS mechanisms and experiments with C. violaceum strains are only one way to screen for anti-QS compounds. Therefore, validation of the obtained findings requires complementary screening assays against other bacterial bioreporters, involving both gram-negative and gram-positive biofilm bacteria.

Early detection of microbial contamination is the key issue for minimizing quality deviations in the beverage industry. Strict standard of process hygiene is one of the best guarantee for the production of microbiologically safe products. The aim of this thesis was to study the efficiency of CIP (cleaning in place) washes, the development of product residues and microbial counts during production cycle, and the surface cleanliness at different points in the production chain at target company beverage plants. In the thesis the microbiological hygiene of the CIP rinse samples from five production lines were studied by using traditional culture methods and ATP measurements. Analyzes of product rinsing samples were used to model the development of product residues and microbial counts during production cycle. Microbiological analyzes of the bottled products were conducted according to standard quality control practices using the filtration and/or pipetting method. A selective DRBC medium was also tested in the analytics of aquatic samples and end products with high microbiological risk. The microbiological cleanliness of critical process surfaces was determined by ATP measurement and Hygicult TPC hygiene test. The results revealed that the deviations observed in the microbiological cultures of the CIP rinse samples were not reflected in the ATP measurement or in the end product analyzes. According to ATP measurements of the CIP rinse samples, 95.7% of the samples were acceptable. Based on the cultivation results, the microbiological quality of the end products was at a good level, which acts as an indicator of the success of CIP wash and hygiene practices. Either there was no significant microbiological growth on Hygicult TPC plates used to test surface cleanliness. On the other hand, organic product residues were detected with ATP measurements during the production, which needs to be taken into account when optimizing hygiene practices. Overall, the process hygiene of the target company is at a good level. However, based on the results of the study, there was no clear relationship between traditional cultivation methods and the ATP method. The bioluminescence technology is not a substitute for microbiological cultivation method, but it is a valid method for monitoring process hygiene to indicate total organic contamination of the target. In a further research it would be beneficial to determine the natural ATP concentration of the raw water used by the target company to facilitate interpretation of RLU values in water samples.