Browsing by master's degree program "Master's Programme in Food Sciences"
Now showing items 21-40 of 173
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(2021)Cowpea (Vigna unguiculata) is one of the most important legumes in the world due to its high nutritional content. Its nutritional value is, however, hindered by different anti-nutrients, such as phytic acid (PA), which can lower the bioavailability of minerals and proteins. PA is a nutritionally significant compound found in many plant materials, such as cereals and legumes. PA is myo-inositol-1,2,3,4,5,6-hexakis dihydrogen phosphate (IP6) by chemical nomenclature. Measurement of PA is challenging, due to its high charges and its low content, amongst other factors. The primary aim in the thesis was to create an accurate, selective, and sensitive UPLC-QTof-ESI-MS method for quantification of PA from legumes, cereals, and other plant materials. The secondary objective was to determine PA content in raw, fermented and phytase-treated white cowpea flour and investigate the effectiveness of the processing methods on PA hydrolysis. PA content in white cowpea has been previously determined with methods lacking the capability to directly measure only PA content, without also adding in the concentration of smaller inositol phosphates (InsP) or other phosphorus containing compounds. Therefore, the presumption was that the measured PA concentration should be lower when using the selective UPLC-QTof-ESI-MS method. Besides white cowpea flour, the concentration of PA in red cowpea, wheat bran, sorghum, wheat fraction and rapeseed protein concentrate flours was also measured to investigate if the method works for other plant matrices as well. The sample preparation method consisted of two-hour extraction in 0.5 M HCl, a neutralization step, lyophilization, reconstitution with 5% MeOH and addition of adenosine 5′-monophosphate monohydrate (AMP) as internal standard. The samples were then analyzed with UPLC-QTof-ESI-MS, with electrospray ionization on negative ion mode (ESI-). The PA quantification method had excellent precision, selectivity, repeatability, and linearity (R2 = 0.991). Accuracy was good and the recovery of 100% resulted in a high level of trueness. The LoD was determined as 3.22 µg/mL but could be possibly lowered. The PA content in white cowpea flour was 5.91 mg/g dry weight. As was presumed, this result was lower than previously reported in literature. The method was also relatively suitable for the other plant samples. However, wheat fraction, rapeseed protein concentrate, and sorghum flours gave unexpected results. In the fermented sample the PA content was 3.30 mg/g and in the enzyme-treated 0.09 mg/g (or 12.4 µg/mL). However, the fermentation and enzymatic treatments did not reduce the PA concentration under the threshold of <3.3 µg/mL, where iron cation chelation still strongly takes place. The processing method could be improved by increasing the phytase dosage or increasing the reaction times to achieve higher hydrolysis of PA.
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(2022)African crops are sustainable and healthy alternative ingredients for potential use in various gluten-free products among traditional African foods. In this thesis maise-based, gluten-free crackers with 50% cereal (amaranth, sorghum and teff) and 50% and 75% legume (Bambara groundnut and cowpea) replacements were produced, and their baking performance and technological properties were examined. The effect of sorghum and cowpea flour's bioprocessing and mechanical raw material modifications on cracker technological and sensory properties was studied. The thesis aimed to solve whether maise and African crop flours could be used in gluten-free crackers and how would they affect nutritional values, baking performance and technological and sensory properties in gluten-free crackers. The nutritional calculations indicated that African crop replacement increased fibre content at least by 2.4% and protein by 1.9 E% compared to 100% maise cracker. Crop replacements improved the dough elasticity and bakability and darkened the cracker surface. African crops and higher protein content increased cracker hardness and improved the rising ability. The highest hardness rate was measured with protein fractionated cowpea (31.55 ± 3.17 N, maise 4.02 ± 1.79%) and puffiness with Bambara groundnut 75% (43.57 ± 3.29%, maise 21.93 ± 0.002%). Raw material modifications changed the sensory profile of sorghum and cowpea crackers significantly by decreasing graininess in sorghum and beaniness in cowpea.
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(2021)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.
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(2020)Infant formulas are breast milk substitutes for 0 to 12-month-old infants. Addition of milk fat to infant formulas leads to an increase in solid fat content. Infant formulas are oil-in- water emulsions in which oil is dispersed into a continuous aqueous phase. Milk fat crystallization leads to partial coalescence and creaming which are types of instability in emulsions. Partial coalescence occurs when two droplets containing crystals collide and they partially coalesce by making contact between their oil phases. The aim of this thesis was to study if milk fat crystallization leads to partial coalescence which leads to a higher rate of creaming or the increasing density of crystallizing droplets leads to a lower rate of creaming. Also, the aim was to study the effect of interfacial layer on partial coalescence. Milk fat crystallization and emulsion stability were investigated from four series of oil-in- water emulsions containing different oils in different concentrations and either whey protein or lecithin as stabilizer. The samples were stored at 5, 20 and 40 °C and measured after 0, 7 and 28 days of storage. The crystallization of bulk fat and oil in emulsions were studied with melting enthalpies measured with differential scanning calorimetry. Emulsion stability was examined with particle size distribution, instability index and creaming velocity measurements. According to the results combining vegetable oil and butter oil, and emulsifying the fat decreases the total enthalpy change and crystallization onset temperature of oils. Mixing vegetable oil and butter oil before homogenization decreased crystallization onset temperature and total enthalpy change because the oils were in same droplet, and made the emulsions behave more like vegetable oil emulsions. Mixing the oils after homogenization made the emulsions behave similarly to butter oil emulsions. Whey protein was found to be a better stabilizer of emulsions than lecithin at 5 and 20 °C, but at 40 °C some Maillard reaction was noticed. It was suspected that the concentration of lecithin in emulsions was insufficient. Based on the results it could be stated that the increasing density due to crystallizing droplets made the emulsions more stable against creaming. Best stability of emulsions containing oil mixtures would be achieved if butter oil and vegetable oil were mixed after homogenization and whey protein used as emulsifier.
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(2024)The primary objective of this thesis was to observe the effect of fermentation of oat and faba bean flour mixture on oat β-glucan. The secondary objective was to define how fermentation conditions affect β-glucan content, pH, total titratable acidity (TTA) and viscosity in oat-faba bean matrix utilizing experimental design and response surface methodology (RSM). As fermentation is a part of manufacturing process of plant-based yoghurt alternatives, this thesis observed the fermentation process in detail to define its effect on β-glucan. The flour mixture consisted of whole grain oat flour, oat bran concentrate, faba bean flour, faba bean protein isolate and water. This mixture was fermented with a commercial yoghurt starter, consisting of Bifidobacterium sbsp., Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus paracasei and Streptococcus thermophilus species. Studied fermentation condition factors were time (7 h, 12.5 h, 18 h), temperature (30 °C, 37.5 °C, 45 °C) and inoculum ratio (0.01 %, 0.1 %, 1% w/w). The relationship between the factors and responses were analyzed with the Central Composite Face-centered (CCF) design and response surface modelling. In all tested fermentation conditions, no significant decrease in β-glucan content was observed. However, relationships between fermentation condition factors and other responses were obtained. All factors had decreasing effect on pH and increasing effect on TTA. All factors contributed to viscosity, but temperature was significantly more effective than others, having positive, non-linear effect.
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(2023)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.
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(2022)Herbs are valued for culinary and health purposes and their metabolism and chemical composition can be influenced with LED lighting. This Master’s Thesis aimed to study how different spectra (green, blue, and white light) affect the sensory properties of hydroponically grown dill (Anethum graveolens L.) and coriander (Coriandrum sativum). The hypothesis was that green light produces more soapy and musty flavours in coriander, whereas blue light produces more citrus and typical coriander-like flavours. For dill the hypothesis was that blue and green light treatments produce stronger flavours compared to white light. A generic descriptive analysis method was chosen, and trained panels created sensory profiles for three light treatment and one commercial coriander and dill samples. Intensities of smell, taste and flavour attributes were evaluated using a line scale (0 = not at all to 10 = extremely) in three replicates. Study was conducted during the COVID-19 pandemic in the sensory laboratory conditions (ISO 8589). One-way ANOVA showed that light treatments had only slight impact on the sensory profiles of coriander and dill. In coriander blue light produced significantly lower lemon odour intensity compared to green light treatment. In dill total odour intensity was significantly lower in blue light sample compared to white light and commercial samples. Otherwise, one-way ANOVA did not show significant differences between samples. However, principal component analysis (PCA) implied that samples differed. Two-way ANOVA results showed that neither panel worked uniformly and deviation among intensity scores was observed. Herb samples proved to be rather difficult to evaluate and more extensive training could have improved panel’s performance. In future consumer study could be performed to study if spectrum affects the hedonic response to these herbs.
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(2024)Elintarviketurvallisuus on ensiarvoisen tärkeää kansanterveyden ja kuluttajansuojan näkökulmasta. Euroopan unionin sisämarkkinat edellyttävät tiukkojen elintarviketurvallisuusstandardien noudattamista kaikilta toimijoilta. Tämä näkyy mm. salmonellan torjunnassa ja valvonnassa. Salmonellan merkitys elintarviketurvallisuudelle on monialainen ja vaikuttaa yksilöiden turvallisuuteen, mutta myös yhteiskuntaan. Useat salmonellatapaukset voivat aiheuttaa terveydellistä vaaraa yksilöille ja samalla nostaa yhteiskunnan terveydenhuollon kustannuksia. Salmonellan merkitys elintarviketurvallisuudelle näkyy erityisesti eläinperäisissä tuotteissa. Tutkimuksen tavoitteena oli selvittää eläinperäisten elintarvikkeiden sisämarkkinatuonnin toimijoiden lainsäädännön tuntemista ja selvittää, minkälaista on näiden käytännön osaamisen sekä toiveet valvojien ohjeistukselle. Tarkoitus oli saada käsitys siitä, minkälaiseksi toimijat kokivat oman osaamisensa harjoittamansa sektorin lainsäädäntöön. Tutkimus koostui toimijoiden haastattelusta puolistandardoidulla teemahaastattelulla, jonka avoimista kentistä selvitettiin toimijoiden hankaluuksia vastaanottotarkastuksien suorittamisessa ja jäljitettävyyden hallinnassa. Lisäksi selvitettiin, mitä asioita toimijat itse pitävät hankalina liittyen elintarvikkeiden tuontiin Suomeen. Tutkimuksessa havaittiin, että osa toimijoista kokee Suomeen vaadittavan byrokratian jopa epäreiluksi, sillä salmonellaerityistakuiden ulkopuolella olevat maat eivät läheskään aina tunnista, mitä asiakirjoja tulisi toimittaa Suomeen, sillä samoja asiakirjoja ei tarvita muualle. Tutkimuksen tuloksista havaittiin, että toimijat kaipaavat lainsäädännön päivityksen ohjeistusta sekä tietopakettia siitä, mistä maista tuodessa tulee saada myös erillinen salmonellatodistus. Havaittiin, että jatkotutkimukselle olisi tarvetta ja varsinkin isomman vastaajajoukon saavuttaminen olisi merkityksellistä. Nyt tutkimukseen ei saatu osallistumaan niin paljon toimijoita, kuin olisi ollut tuloksien kannalta tärkeää. Vähäinen vastaajajoukko jätti tuloksiin tulkinnanvaraa.
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(2022)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.
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(2020)Faba bean (Vicia faba L.) is a healthy and ecological pulse crop. Nevertheless, it contains antinutritive compounds, including lectins. Lectins are proteins or glycoproteins that bind to carbohydrates. Faba bean lectin is called favin and it binds specifically to mannose- and glucose-like carbohydrates. Agglutinatination assays have been traditionally used for the determination of lectins. These assays are, however, often inaccurate. The aim of this study was to adapt and optimize a method for the quantification of faba bean lectin and analyze lectin levels in untreated and treated faba beans. Enzyme-Linked Lectin Assay (ELLA), which is based on the ability of lectins to bind to specific carbohydrates, was adapted in the study. The hypothesis was that the method is suitable for the quantification of faba bean lectin. The commercial lectin standard did not react in the assay and thus the quantification of lectins was not possible. The faba bean samples, however, reacted and the absorbance values of varying samples were compared. The protein-rich faba bean fractions gave the highest absorbance values. Particle size affected the determination of lectins. Heating was efficient in lowering the absorbance values. Long-time roasting and boiling were the most efficient methods to reduce the binding capability of lectins.
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(2023)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.
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(2021)Enzyme treatments have been able to reduce the amount of oligosaccharides and phytates in legumes. Enzyme treatment has the potential to improve the sensory properties of the product and reduce the stomach symptoms they cause. The aim of the study was to find out how enzyme treatment affects to the sensory properties of spoonable yogurt-like faba bean and pea-based snack samples. In addition, an online survey was made to map stomach symptoms caused by legumes and to study their effect on the use of legumes and legume foods. The methods used in the study were generic descriptive analysis with a trained panel (11 panelists) and an online survey made with E-lomake (227 respondents). In addition, the benefit data from the second study of the project for pea snacks were used (27 evaluators). In the generic descriptive analysis, there were a total of 6 spoonable snack samples to be examined (3 faba bean samples and 3 pea samples). Both raw materials had a control sample (no enzyme treatment) and two differently enzyme treated samples. In the generic descriptive analysis, the panel evaluated 12 properties from the samples: color, fruity and legume-like odor, runniness, grainy, powderiness, thickness, sweet, bitter, legume-like, bitter aftertaste and total intensity of aftertaste. Enzyme treatment had an effect on texture and mouthfeel properties, but not on taste, color, or odor. As a result of the enzyme treatment, the structure thickened and became smoother. The raw material had an effect on all the properties to be evaluated, except for the legume-like flavor. Enzyme treatment had no effect on the pleasantness of spoonable pea snacks. According to the survey, the most common symptoms caused by legumes were flatulence and bloating. Of the legumes and legume foods, chickpeas and pea soup were the most common foods to cause symptoms. More than half (about 65 %) of the respondents stated that they would definitely or probably eat more legumes if they did not cause stomach symptoms. More than half (67 %) would also be absolutely or probably willing to try enzyme-treated legume foods. Based on the results, it is worth further investigating the effects of enzyme treatment on sensory properties, especially in terms of structure / mouthfeel. In addition, the effect of fermentation on the sensory properties of pea and faba bean spoonable snacks should also be studied, as fermentation has been found to improve the sensory properties and nutritional value of plant-based spoonable snacks. Based on the responses to the survey, there seems to be a demand for legume products that cause less stomach symptoms.
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(2021)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.
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(2020)Securing an adequate protein intake raises questions for the future, and various plant protein products have grown in popularity in recent years. Tofu is one of the most popular vegetable protein products due to its versatility. Also, its different structural types are appealing to consumers. One way to increase the value of other grain legumes closer to soybeans would be to develop a tofu analogue from them. Faba beans are potential for this purpose, as they can be cultivated under the northernmost conditions, they are as rich in protein like soybeans and the proteins within soybean and faba bean are similar in structure. This study complements research related to the gelation of faba bean proteins. The aim was to study how different coagulants, their contents and different faba bean protein contents in the emulsion affect the resulting gel structure. The gels produced by each coagulant were examined separately so that the variables, i.e., coagulant and protein contents, were given three different values. The protein content of the emulsion was either 6, 7 or 8% (w/v), and the contents of coagulants were as follows: transglutaminase (TG) 5, 25 or 50 U/g of protein, gluconodeltalactone (GDL) 0.3, 0.65 or 1%, citric acid 0.14, 0.16 or 0.18% and calcium sulphate (CaSO4 · 2 H2O) 0.5, 1 or 1.5% (w/w). The structures of the gels were compared based on the results of Texture Profile Analysis (TPA) and sensory observations, and in addition, the samples were examined for the interactions formed between the proteins. This was done by dissolving the gels in various solvents. Of the gels studied, the most different structure was produced by transglutaminase, which provided a solid-like gel structure at the highest content combined with the highest protein content in the emulsion. Its TPA value for hardness was the highest. The interactions between proteins also differed most when comparing the results of other gels to transglutaminase gels. A probable explanation for these results was the strong isopeptide bonds formed by TG. GDL, citric acid or calcium sulfate did not produce such a solid gel structure, but the structures of the samples were much softer, part almost liquid. The protein content had a statistically significant effect on the hardness of gels coagulated with TG and calcium sulfate, among others. The coagulant content also affected the results of the TPA measurements, but they had less effect than the protein content.
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(2023)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.
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(2021)Oat β-glucan is well known for its health benefits, which are related to its rheological behavior in the gut. The objective of this thesis was to investigate the extractability and viscosity of β-glucan from oat bread under physiological conditions and to see whether there were varietal differences. Oat flours of twenty different cultivars were used to bake breads which were subjected to in vitro digestion. The resulting extracts were studied for viscosity using a rheometer, and the β-glucan contents of the breads and the extracts were determined to evaluate the extractability. In addition, the effect of flour particle size on extractability was investigated. Variance in the in vitro extractability of β-glucan was seen between cultivars, which was not explained by flour particle size. All samples produced highly viscous extracts, and the viscosities increased sharply with increasing β-glucan concentration, which suggests that the β-glucan was not extensively degraded during the breadmaking process. The viscosities also varied between cultivars, as some exhibited considerably higher viscosities at similar concentrations. The results indicate that the β-glucan from the oat breads would have good capacity to increase viscosity in the intestine, although varietal differences were observed.
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(2020)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.
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(2022)Previous studies have demonstrated that legume proteins have high potential to lose their native functional properties during conventional wet fractionation, since heating and drying in the processes can lead to protein aggregation and solubility reduction. However, the effect of this process on faba bean protein has not been investigated thoroughly before, according to the literature review. Therefore, the aim of this study was to investigate the influence of wet fractionation process with and without spray drying on faba bean protein gelling properties. The hypothesis was that protein isolate produced with isoelectric precipitation without spray drying would have better solubility and gelling properties than spray dried isolate. Faba bean protein concentrate (FBPC) was used to prepare faba bean protein isolate with alkaline extraction followed by isoelectric precipitation, which was then dispersed into water and neutralized (faba bean protein slurry, FBPS). Some of FBPS was spray-dried (pilot faba bean protein isolate, FBPI-P). Commercial faba bean protein isolate (FBPI-C) was used as a reference sample. Their (FBPC, FBPS, FBPI-P, FBPI-C) functionality was studied by measuring thermal denaturation (DSC), protein solubility, particle size and light microscope pictures. In addition, glucono delta lactone (GDL) induced oil-in-water emulsion gels were prepared from FBPS, FBPI-P and FBPI-C. Water holding capacity (WHC), rheological and texture properties were measured from the gel samples. Surprisingly the obtained results of faba bean in this study were different from previous research on other legume proteins. It was found that spray-dried FBPI-P showed better gelling properties than wet based FBPS. This might be due to differences in thermal denaturation. Based on DSC curves, FBPI-C was found to be fully denatured and in a poor solubility. Interestingly, GDL-induced gels had strongest gel properties, which might be highly related to industrial manufacturing process of FBPI-C. When considering the theoretical environmental impact of these processes, FBPS could show potential of being more environmentally friendly process, as it could be more energy efficient than processes which require drying and heating. It was demonstrated that FBPS showed almost as good functional properties as the pilot spray-dried isolate. Hence, FBPS could work as functional and more environmentally friendly option for food industry. Future study could be conducted in near future about FBPS safety, technological applications, process optimization and environmental impact.
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(2023)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 .
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(2023)This master's thesis investigated consumers' insights on sustainability, animal welfare, and nutrition-related qualities to increase the attractiveness of red meat. The study focused on Finnish young adult (18 to 35-year-old) flexitarians, who have reduced their red meat consumption and incorporated plant-based proteins into their diets. This study conducted a quantitative analysis through a questionnaire (n=588) and explored consumer dietary behavior, trust in labeling, social pressure, and opinions regarding rational and value-based quality factors through willingness to buy and pay. For Finnish young adult flexitarians, environmental, ethical, and nutritional factors emerge as the most influential aspects when changing dietary behaviors. The effect of social pressure is only mild, but flexitarians do exhibit greater bad conscience for red meat consumption. Domesticity is recognized as an important quality attribute for all respondents in this study. In contrast to other meat-eating consumers, flexitarians perceive plant proteins as healthier alternatives to red meat but still acknowledge its nutritional benefits. Most consumers, especially flexitarians, value ethical production and express willingness to pay more for meat with good animal welfare. Consumers' trust in company-provided sustainability and health-related information about their products is found to be lower than with general packaging information. The study proposes solutions related to carbon footprint and animal welfare labeling among others and emphasizes the significance of objective information and transparency. This master's thesis aids in understanding the quality factors necessary to maintain consumer acceptance of red meat and sheds light on the key drivers prompting consumers to adopt a more plant-based diet. The research guides companies and the meat industry on how to enhance their practices and bolster the attractiveness of red meat for future consumers.
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