Browsing by master's degree program "Elintarviketieteiden maisteriohjelma"

Poultry meat has become popular in human diet and to secure the growing demand of poultry meat, breeders have developed broilers with fast growth and high breast muscle yield. Because of this genetic selection modern broilers are suffering from various quality defects in their breast muscles, one of which is called WB myopathy. The aim of the thesis was to study whether exercise, WB status or age have effects on ultimate pH and glycolytic potential (sum of total glucose and lactic acid content, given as lactate) in M. pectoralis major of modern broilers chickens. A total of 154 post-rigor breast muscle samples of male broilers of hybrid Ross 308 were used in this study. Broilers were divided randomly into three groups (A-C). Group A birds were not subjected to any exercise during the experiment. Group B birds lived 25 days exactly like group A but after that the drinking water dispensers was elevated to a higher level. Group C birds had their drinking water dispensers elevated to a 5 cm higher level after three days, and it was risen stepwise to 25 cm during the study. Broilers were slaughtered randomly from different groups at 20, 30 or 41 days old. Group B results were disregarded due to technical problems. Initial and ultimate pH, total glucose, free and in glycogen, and lactic acid contents for glycolytic potential, were determined from the breast muscle samples. The results showed that there were no differences between groups A and C (p > 0.05). There were differences between normal and WB cases in ultimate pH (pHu; p = 0.000), total glucose content (p = 0.000), lactate content (p = 0.007) and glycolytic potential (p = 0.000), but the pH values 5 minutes after death showed no significance (pH5; p = 0.190). There were differences in pHu, total glucose and glycolytic potential (p = 0.000), and lactate (p = 0.007), between ages 20, 30 and 41 days old birds. As the severity of WB increased in the breast muscle, the pHu increased and total glucose, lactate content and glycolytic potential decreased. The correlations showed significant relationships between WB score and all the above variables (p < 0.000). The results of the current study show that exercise does not have an effect on the levels of carbohydrates in M. pectoralis major of modern broiler chickens, but WB status and increasing slaughter age result a decrease in glycolytic potential and increase in ultimate pH.

Sorghum (Sorghum bicolor L. Moench) has high contents of phenolic compounds which have both beneficial and antinutritional health effects, including forming insoluble complexes with proteins. This is significant because sorghum has low protein digestibility. Lactic acid bacteria (LAB) fermentation has been found to decrease and modify sorghum phenolic compounds and condensed tannins. The aim of this thesis was to evaluate the effects of LAB fermentation on the phenolic compounds in white and red sorghum using a metabolomics approach. The hypothesis was that fermentation would degrade phenolic compounds into smaller metabolites. Free phenolic compounds were extracted from sorghum using 80% ethanol. The samples were analysed using ultra-performance liquid chromatography coupled with a photodiode-array detector and quadrupole time-of-flight mass spectrometry (UPLC-PDA-Q-TOF). In order to identify phenolic compounds, both targeted and untargeted metabolomics approaches were used. Multivariate analysis was employed to determine compounds with different abundances between sample groups. The study confirmed the identification of 40 compounds, 37 of which were phenolic compounds, and 23 were distinct between sample groups. Red sorghum contained more flavonoids and condensed tannins compared to white sorghum. Native samples were statistically different from fermented samples, with most changes involving the release of phenolic acids from their conjugated forms and an increase in phenolamines. The metabolomics approach effectively covered the wide range of phenolic compound analysis in sorghum.

Merkittävä osa elintarvikeperäisistä mikrobiologisista ja kemiallisista vaaroista kasvaa, leviää tai syntyy kuluttajien kotona. Kuluttajat vaikuttavat ruoan turvallisuuteen käsittely- ja säilytystottumuksillaan, joiden arviointi on nykyisessä riskinarvioinnissa vaikeaa puutteellisen aineiston takia. Jotta riskinarviointi olisi paikkansapitävä, ja sen mukaan luodut ohjeistukset, säädökset ja lait mahdollisimman kohdennettuja, tulee kuluttajien vaaroille altistumisen arviointi olla aiempaa tarkempaa. Tutkimus suoritettiin Ruokaviraston toimeksiantona, ja sen tarkoitus oli luoda valmis kyselypohja riskinarvioinnin tueksi. Kyselylomakkeiden avulla pyrittiin selvittämään kuluttajien kalan ja lihan käsittely- ja säilytystottumuksia kotioloissa, millä on merkittävä vaikutus kemiallisille ja mikrobiologisille vaaroille altistumisessa. Tutkimus koostui kahden kyselylomakkeen luomisesta ja niiden validiuden arvioimisesta yksilöhaastatteluilla (n=30, 18–83 v.). Tutkimuksessa havaittiin, että lomakkeet eivät sellaisenaan olleet valmiita käyttöönottoon. Osa kysymyksistä ei soveltunut haluttuun tarkoitukseen, eikä niillä täten saatu kerättyä tarvittavaa aineistoa. Ennen lomakkeiden käyttöönottoa myös kyselyissä käytettyä 7-portaista ankkuroitua asteikkoa tulee muokata numeerisemmaksi, sillä sanalliset ankkurit olivat monitulkintaisia. Tässä tutkimuksessa ehdotettujen muokkausten jälkeen lomakkeiden validiteetti olisi tärkeää tutkia myös seurantatutkimuksen avulla, mutta myös sellaisenaan lomakkeet tuovat tarvittavaa aineistoa kuluttajien kotikäyttäytymisestä.

Cellular agriculture (CA) utilizes cells to produce alternatives for conventional animal or plant-based foods. Concepts for CA are available, but their feasibility for large scale production is not yet well documented. The aim of this work was to compare CA and conventional milk chain in terms of energy demand. Enzyme production was included to the analysis as a benchmark to precision fermentation. In the life cycle analysis (LCA), life cycle inventory was compiled from scientific literature for CA and enzyme production. Inventory data for milk powder production was taken from Valio Carbo Calculator. A functional unit of 1 kg protein was applied. Cumulative energy demand for each product was re-calculated applying a cradle-to-gate system boundary. Background data was compiled from Ecoinvent and Agri-footprint databases and analyzed with OpenLCA. Milk protein in general has lower requirement in non-renewable and renewable CED than CA alternatives. Main contributors to CED in CA were electricity, thermal energy, carbon source and in some scenarios cleaning-in-place (CIP). CED values were 185 MJ/FU, 179 MJ/FU – 1007 MJ/FU and 410 MJ/FU – 166 385 MJ/FU for milk protein production, CA, and enzyme production, respectively. Moreover, enzyme production revealed that CED of CA has potential to have much higher values than reported on CA production. In the future, studies with continuous fermentation utilizing different by-products and including more impact factors should be pursued.

Glucuronoxylans (GX) from birch and galactoglucomannans (GGM) from spruce are capable of forming and stabilising oil-in-water emulsions. Phenolic compounds co-extracted with wood hemicelluloses enhance the stability of an emulsion. The stabilising mechanisms of emulsions prepared from GGM have been studied in detail, while emulsions stabilised by GX require further investigation due to the complexity of their chemical compositions. On the contrary to GGM-based emulsions, pectin was found at the interface of GX-based emulsions. We hypothesise that pectin plays a role in emulsification and affects the bimodal droplet size distribution of an emulsion. Therefore, this study aimed to assess the functionality of pectin in GX-based emulsifiers with pectinase. First, pectinase treatment conditions were optimised, namely reaction medium, time, temperature and pectinase dosage. The enzymatic hydrolysis of pectin was confirmed quantitatively by gas chromatography (GC). To investigate the role of pectin in emulsion stabilisation, rapeseed oil-in-water emulsions were prepared from pressurised-hot-water-extracted (PHWE) spray-dried GX (sGX), sGX treated with pectinase (p-sGX), sGX treated with pectinase and centrifugation (c-sGX), ethanol-precipitated GX (eGX), eGX treated with pectinase (p-eGX), and eGX treated with pectinase and centrifugation (c-eGX). The stability of the 6 emulsions was measured in a 2-week accelerated storage stability test. Phenolic compounds originating from lignin were characterised by pyrolysis gas chromatography-mass spectrometry (pyrolysis GC-MS) to monitor the changes of lignin contents before and after pectinase treatment. It is concluded that the optimum conditions of pectinase treatment were: reaction medium: 0.1 M sodium acetate buffer (pH 4.5), reaction temperature: 50 °C, reaction time: 2 hours, pectinase dosage: 304 U per gram of birch hemicellulose. Results from GC analysis of free monosaccharides confirmed that only pectin was hydrolysed under the abovementioned pectinase treatment conditions and that the hemicellulose backbone structure remained intact. Emulsions prepared from sGX remained stable for over 2 weeks, while creaming was observed in emulsions stabilised by p-sGX and c-sGX during the second week of storage. Emulsions prepared from eGX, p-eGX, and c-eGX remained stable for over 2 weeks. Results from pyrolysis GC-MS indicated that pectinase treatment removed some of the phenolic compounds in GX. Therefore, it was concluded that associations existed among GX, lignin, and pectin. Pectin took part in the formation and stabilisation of emulsions prepared from sGX and eGX by connecting lignin to GX.

Plant-based milks can be unstable during storage due to the colloidal structure of these drinks. In general, e-coded additives are used to increase the viscosity of the drinks and hence, improve stability. Oat beta-glucan, microbially or enzymatically produced exopolysaccharides, such as dextran, and flaxseed mucilage are natural hydrocolloids that are known to have the ability to increase viscosity. These hydrocolloids could potentially be used to replace e-coded additives. The aim of this thesis was to study the stabilizing potential of oat beta-glucan, exopolysaccharides, and flaxseed mucilage in oat drinks. Oat drinks with added hydrocolloids were compared to control samples that were oat drink without added hydrocolloids and oat drinks with pectin at concentrations of 0.2% and 0.4%. Oat beta-glucan, exopolysaccharides, and flaxseed mucilage were added to the prepared drinks by replacing 10% of water with the extracts. Additionally, stabilizing properties of isolated and freeze-dried microbially produced dextran was studied by adding it to the drinks at concentrations of 1.5%, 1.0% and 0.5%. Stability of the oat drinks was assessed during a 14−day storage period by measuring the viscosity, pH, and phase separation. Results of this study demonstrated the stabilizing potential of the natural hydrocolloids. The addition of hydrocolloids increased the viscosity in all samples. The inclusion of natural hydrocolloids led to a similar stability, and in some cases also significantly lower viscosity, compared to pectin added drinks. Oat beta-glucan had a remarkable positive impact on the stability of oat drinks. This was most likely due to the network formation of oat beta-glucan molecules, which decreased the sedimentation of colloidal particles. Enzymatically produced dextran also improved the stability of oat drinks, which might be attributed to the viscosity-increasing -capacity of dextran. However, the stabilizing role of microbially produced exopolysaccharides was not shown. For future study, the molecular interactions of natural hydrocolloids in the colloidal solution should be investigated.

New alternatives for meat as the main source of protein are needed due to the negative impact of meat production on the environment and its high utilization of land sources. Vegetable proteins offer a more sustainable choice for meat and they can be processed into a structure that resembles meat using extrusion technology. The aim of this study was to produce a minced meat analogue using extrusion technology. The goal was to gain more information on the textural properties, colour and sensorial features of the meat analogue. In the experimental part, extrudates with replicates were produced from plant protein and fibre concentrate. Three differently processed samples were analysed. Texture analyser was used to measure the gumminess, springiness, chewiness, hardness, adhesiveness and shear energy of the samples. In addition, colour and moisture content were measured and a sensory experiment was conducted. According to the results, the content of the plant protein and fibre concentrate affected the textural properties and the colour of the samples. The results also showed that the composition of minced meat analogue had different effect on the textural properties depending how the sample was processed. In the sensory experiment, the reference sample (minced meat) had significantly higher score of pleasantness compared to extrudate containing samples. No significant differences were observed among the extrudate containing samples. This study showed that a product with some similarities to minced meat can be produced using extrusion technology with plant protein and fibre concentrate. For the development of the meat analogue, a more comprehensive sensory analysis would help to gain more information about the development targets of the product.

The literature review detailed the theoretical background for this study, identified the possibility about development of faba bean protein stabilized emulsion for food products and studied the effect of increased oil addition on the structure of emulsions. The practical work was divided into three parts emulsion analysis, emulsion gel analysis and sensory evaluation. Various research methods were applie d to support this study, including droplet size distribution , droplet charge ζ potential), texture evaluation, and rheological analysis. This study showed that oil addition increased emulsion droplet size, as well as the absolute value of ζ potential . Emulsifying activity index (EAI) and emulsion stability index (ESI) decreased with increasing oil concentration. F aba protein stabilized emulsions were better stabilized by oil addition , compared with those without oil additi on . From texture analysis of gel properties, firmness improved with increasing oil concentrations (0% 30%). In addition, rheolog ical analysis for faba yogurt samples showed that increasing oil concentrations improved the viscosity of the faba yogurt samples. T he results also illustrated that increasing oil concentrations led to increased deformation meaning the emulsion gels were more easily destroyed with increasing oil concentrations (0 30%). Oil addition resulted in higher whiteness when compared with samples without oil. Sensory evaluation by a professional panel for faba yogurt samples indicated that samples with 20% oil concentration w ere the most preferred and had the highest overall quality .

There is a growing demand for new, environmentally sustainable, clean label food additives driven by consumers’ desire for healthier and sensorially appealing food products. The aim of this thesis is to study a novel, “clean label” food additive called fibrillated microcrystalline cellulose (fMCC) in the formation of emulsions, elucidate its stabilization mechanism, as well as emulsion storage stability at room temperature over time. To this aim, oil-in-water emulsions with fMCC and vegetable oil were formed via mechanical treatment. It was found that the oil droplets anchor on the surface of the fibrils attached to the microcrystalline cellulose. After homogenization fMCC formed large, entangled aggregates that were located in the continuous phase of the emulsion. This increased the viscosity of the emulsion, which contributed to the stability of the system. During storage, further aggregation was observed. High oil content emulsions exhibit some coalescence, while oil droplets in low oil content emulsions remained unchanged. In this thesis, it was shown that fMCC can be used as a suitable and environmentally sustainable ingredient for emulsion formation and stabilization, with the added benefit of increasing the fiber content of many processed foods and thus increasing their nutritional value.

Gluteeniton kauraleivonta on teknologisesti haastavaa, sillä viskoelastisen gluteeniverkoston puuttuessa kaurataikinoita on hankalaa työstää ja kauraleivät jäävät usein tiiviiksi, kosteiksi ja tahmeiksi. Hyväksyttävän rakenteen aikaansaanti on vaikeaa ja gluteenittomille leiville on tyypillistä, että ne vanhenevat nopeasti. Leivän vanhenemiseen johtavina tekijöinä pidetään tärkkelyksen uudelleenkiteytymistä ja veden liikkumista leivässä säilytyksen aikana. Tutkimuksen tavoitteena oli parantaa gluteenittoman kauraleivän säilyvyyttä käyttämällä taikinassa esiliisteröityä tärkkelystä. Tutkimuksen hypoteesina oli, että velliksi esiliisteröidyn kaurajauhon käytöllä vesi saadaan sidottua tiukemmin tärkkelysgeeliin, jolloin säilytyksen aikana tapahtuva veden liikkuminen leivässä hidastuu. Kun rakennetta pehmentävä vesi puristuu hitaammin ulos tärkkelysgeelistä ja liisteröityneisiin, amorfisiin tärkkelysalueisiin on sitoutunut enemmän vettä, on leivän rakennetta kovettavien tärkkelyskiteiden muodostuminen hitaampaa. Lisäksi tutkimuksessa vertailtiin kauravellin hapatusta mikrobiologisella ja kemiallisella menetelmällä. Mikrobiologisen hapatuksen aikana jauhopartikkelit ehtivät vettyä ja liueta edelleen, ja tällä oletettiin olevan rakennetta pehmentävä vaikutus. Tutkimuksen kokeellisessa osassa kauraleipien rakenteen kovettumista tutkittiin kaksivaiheisella puristustestillä aineenkoestuslaitteella ja tärkkelyksen uudelleenkiteytymistä seurattiin DSC-kalorimetrillä. Taikinoiden ominaisuuksia havainnollistettiin erilaisin geelitestein. Tutkimuksessa havaittiin, että esiliisteröity kauravelli lisäsi kaurataikinan kaasunpidätyskykyä ja kasvatti kauraleivän ominaistilavuutta. Kemiallisesti hapatettua velliä sisältäneessä kauraleivässä rakenteen kovettuminen oli hitainta ja leipä oli tilastollisesti pehmein kuudenteen säilytyspäivään asti. Mikrobiologisesti hapatetun vellin käyttö taas nopeutti kauraleivän rakenteen vanhenemista. Esiliisteröidyn vellin käyttö pehmensi gluteenittoman kauraleivän rakennetta liisteröimällä enemmän tärkkelystä amorfiseen muotoon ja hidastamalla veden liikkumista leivässä säilytyksen aikana. Kauravellin kemiallinen hapatus pehmensi kauraleivän rakennetta edelleen, ja rakenne oli vellitöntä leipää pehmeämpi vielä kuudentena säilytyspäivänä. Tutkimuksessa onnistuttiin pidentämään gluteenittoman kauraleivän pehmeää aikaa käyttämällä taikinassa kemiallisesti hapatettua, esiliisteröityä velliä.