Browsing by Subject "protein"

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  • Rekola, Kristiina (Helsingfors universitet, 2015)
    Chemical composition of oats and its suitability for baking were reviewed in the literature part. The special features of baking without gluten and possibilities to increase the quality of gluten-free bread were also discussed. The aim of the experimental research was to develop high protein gluten-free oat-based bread. The effect of different protein concentration on structural, textural and sensory properties of gluten-free oat bread was studied. Also the effect of processing method on bread quality was studied by using sourdough technology and straight dough technology. Gluten-free oat bread recipe and baking protocol as well as sourdough fermentation conditions were optimized on the basis of preliminary trials. Oat-based breads with varying protein content were baked by using straight dough and sourdough technologies. Reference sample was oat-based bread without added protein. Specific volume, moisture content, texture profile analysis (crumb hardness, chewiness and resilience) and starch retrogradation of gluten-free breads were analysed. For shelf life measurements, breads were stored in plastic bags at room temperature from 1 to 3 days. Sensory profile of bread samples were evaluated on the day of baking by a trained panel. Descriptive analysis method was used. Palatable high protein gluten-free oat-based bread was obtained in this study. Increasing amount of protein improved the crumb structure and shelf life of gluten-free breads. All of the protein supplemented breads had agreeable sensory profile. Sourdough did not further improve the quality of high protein gluten-free bread except for increased aroma intensity. Oats and its fractions can be successfully applied as an ingredient for gluten-free baking to enhance the nutritional quality.
  • Fogelholm, Mikael; Anderssen, Sigmund; Gunnarsdottir, Ingibjorg; Lahti-Koski, Marjaana (2012)
  • Tischmann, Lea; Drummen, Mathijs; Joris, Peter J.; Gatta-Cherifi, Blandine; Raben, Anne; Fogelholm, Mikael; Matias, Isabelle; Cota, Daniela; Mensink, Ronald P.; Westerterp-Plantenga, Margriet S.; Adam, Tanja C. (2020)
    An unfavorable lipid profile and being overweight are known mediators in the development of cardiovascular disease (CVD) risk. The effect of diet, particularly high in protein, remains under discussion. Therefore, this study examines the effects of a high-protein (HP) diet on cardiometabolic health and vascular function (i.e., endothelial function, arterial stiffness, and retinal microvascular structure), and the possible association with plasma endocannabinoids and endocannabinoid-related compounds in overweight participants. Thirty-eight participants (64.5 +/- 5.9 (mean +/- SD) years; body mass index (BMI) 28.9 +/- 4.0 kg/m(2)) were measured for 48 h in a respiration chamber after body-weight maintenance for approximately 34 months following weight reduction. Diets with either a HP (n= 20) or moderate protein (MP;n= 18) content (25%/45%/30% vs. 15%/55%/30% protein/carbohydrate/fat) were provided in energy balance. Validated markers for cardiometabolic health (i.e., office blood pressure (BP) and serum lipoprotein concentrations) and vascular function (i.e., brachial artery flow-mediated vasodilation, pulse wave analysis and velocity, and retinal microvascular calibers) were measured before and after those 48 h. Additionally, 24 h ambulatory BP, plasma anandamide (AEA), 2-arachidonoylglycerol (2-AG), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and pregnenolone (PREG) were analyzed throughout the day. Office and ambulatory BP, serum lipoprotein concentrations, and vascular function markers were not different between the groups. Only heart rate (HR) was higher in the HP group. HR was positively associated with OEA, while OEA and PEA were also positively associated with total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol concentrations. Vascular function markers were not associated with endocannabinoids (or endocannabinoid-related substances). In conclusion, the HP diet did not affect cardiometabolic health and vascular function in overweight participants after completing a weight-loss intervention. Furthermore, our data indicate a possible association between OEA and PEA with TC and LDL cholesterol.
  • Zou, Ling (Helsingfors universitet, 2009)
    Andean lupin (Lupinus mutabilis Sweet) is a potential oilseed crop, with a very high protein content (40–45%) and 15–20% oil content. It is valued as an alternative protein source for both human and animal consumption, and like several other lupin species, has a potential role in phytoremediation. Previous experience in central and southern Europe has shown the crop to have low and unstable yields with high sensitivity to heat and drought during the grain–filling stage. The species may therefore be more suitable for cool–temperate climates, as it comes from similar altitudes and latitudes as potato. Therefore, an experiment was set out to quantify the responses of Andean lupin to heat stress, using both gradually and suddenly rising temperatures during grain filling. In preliminary tests 60 accessions from 4 germplasm banks were screened for time to flowering and daylength sensitivity. For this experiment, 3 accessions were chosen, 478435, 457972, 457977, with vegetative phase durations of 44, 53, 64 days from sowing to first flower, respectively. Forty two plants of each accession were sown and reduced to 30 on the basis of uniformity. Plants were grown in a glasshouse with 22 °C, 18 h days and 18 °C, 6 h nights until about 25 days after flowering. Ten plants of each accession were subjected to one of the following treatments: control (continuing in the same glasshouse conditions), sudden heat stress (transferred to a growth chamber and subjected to 38 °C from 11:00 to 15:00) or gradual heat stress (transferred to a growth chamber and subjected to temperature increases of 4 °C day temperature and 2 °C night temperature, with the final two days at 38 °C from 11:00 to 15:00). The plants were returned to the glasshouse and when mature, the seeds were harvested and pooled into 3 replicates per accession and treatment for quality analysis. Seed protein, oil, soluble sugar, ash and moisture content were determined. Data were calculated on the basis of percentage of overall seed mass and also on a milligrams per seed basis in order to reflect the seed physiology at grain–filling stage. Sudden heat stress had greater effects on seed composition than gradual heat stress. When compared with control, sudden heat stress resulted in more loss of every component than gradual heat stress, on a per–seed basis, in all 3 accessions and the responses of the accessions to the sudden stress were not statistically different. Under sudden heat stress, mean seed weight declined by 70%, protein content by 70%, oil content by 85%, ash content by 50%, and soluble sugar content by 75%. The accessions responded differently, however, to the gradual heat stress. Accession 478435 experienced significantly greater reduction in seed weight, protein and ash content than accessions 457972 and 457977. Oil content per seed and soluble sugar content per seed were also lower in 478435 than in the other two cultivars, but the difference was not significant. On the flour basis, sudden heat stress increased ash content and decreased oil content and soluble sugar content significantly in all accessions. Accession 478435 had highest value in ash content at significant level. Under gradual stress, protein and ash content were increased while oil mass and soluble sugar mass were decreased. 478435 had significantly higher protein mass and ash mass in flour with respectively 57% and 5.1%, 457977 had significantly higher soluble sugar content with 112 mg/g. The results showed that heat stress can have a significant effect on the quantity and quality of seed yield in Andean lupin. While all tested accessions were severely susceptible to sudden heat stress, gradual stress identified differences between accessions, with one being much more susceptible than the other two. The most susceptible accession was the earliest to flower. Gradual heat stress allows better resolution than sudden heat stress when screening germplasm for heat tolerance.
  • Peltola, Taru; Kaljonen, Minna; Kettunen, Marita (Taylor & Francis, 2020)
    Sustainability Science Practice Policy 16 1 (2020)
    Reducing meat consumption has become a key concern in attempts to respond to climate change. We explore possibilities to empower collectives of people to reflect on their eating preferences by organizing protein demonstrations for Finnish students aged 10‒16. We analyze the protein demonstrations as public experiments – specific arenas allowing people to experience alternative foods and deliberate on sustainable eating. Video recordings of the demonstrations revealed two key interactive modes that were crucial in this undertaking. Tasting as an embodied form of interaction allowed the students to share their experiences about the foods while playful interactions created a more inclusive and informed setting for engagement. Unlike conventional public engagement methods, the protein demonstrations enabled participants to share their emotions and feelings and to express their doubts and concerns about the idea of sustainable eating. The project revealed tensions between visceral experiences and socially constructed ideas of eating that might otherwise remain unaddressed. The protein demonstrations were thus a means of systematically producing conditions that enabled the elements influencing dietary transition to be made visible and discussed. Addressing these elements is crucial in achieving long-term and internally motivated changes in unsustainable eating preferences.
  • Taha, Lamia (Helsingin yliopisto, 2021)
    The endoplasmic reticulum (ER) is an important organelle of the cell where a high number of proteins are synthesized and modified to obtain their final structure. Therefore, the ER stress, which is caused by accumulation of unfolded proteins in the ER, is not to be taken lightly since it could contribute to many diseases, such as cancer and neurodegenerative diseases. The response to the ER stress is the unfolded protein response (UPR), which is an adaptive system that helps in adjusting for increased folding needs within the ER. One of the main protein branches in the UPR is inositol requiring enzyme 1 (IRE1). IRE1 detects the status of protein folding inside the ER and initiates the UPR signaling pathway to achieve either normal folding status or cell death. The aim of this research was to express yeast IRE1 in E.coli and human IRE1 in insect cells, purify with affinity chromatography and study the IRE1’s crystal structure with a small molecule modulator that could possibly enhance its activity. The protein was expressed successfully and purified with glutathione S-transferase (GST) tag, and the activity of the pure protein was determined. The structural studies were not fully completed since the absolute purity and yield that was necessary for crystallization was not achieved due to loss of protein during gel filtration and precipitation. Based on the results it is likely that the structure of the protein could be solved and further biochemical and structural studies with F10 are possible.
  • Niskakoski, Anni (Helsingin yliopisto, 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.
  • Meri, Seppo; Haapasalo, Karita (2020)
    Complement-mediated inflammation or dysregulation in lipid metabolism are associated with the pathogenesis of several diseases. These include age-related macular degeneration (AMD), C3 glomerulonephritis (C3GN), dense deposit disease (DDD), atherosclerosis, and Alzheimer's disease (AD). In all these diseases, formation of characteristic lipid-rich deposits is evident. Here, we will discuss molecular mechanisms whereby dysfunction of complement, and especially of its key regulator factor H, could be involved in lipid accumulation and related inflammation. The genetic associations to factor H polymorphisms, the role of factor H in the resolution of inflammation in lipid-rich deposits, modification of macrophage functions, and complement-mediated clearance of apoptotic and damaged cells indicate that the function of factor H is crucial in limiting inflammation in these diseases.
  • Drummen, Mathijs; Tischmann, Lea; Gatta-Cherifi, Blandine; Fogelholm, Mikael; Raben, Anne; Adam, Tanja C.; Westerterp-Plantenga, Margriet S. (2020)
    Background: Weight loss has been associated with adaptations in energy expenditure. Identifying factors that counteract these adaptations are important for long-term weight loss and weight maintenance. Objective: The aim of this study was to investigate whether increased protein/carbohydrate ratio would reduce adaptive thermogenesis (AT) and the expected positive energy balance (EB) during weight maintenance after weight loss in participants with prediabetes in the postobese state. Methods: In 38 participants, the effects of 2 diets differing in protein/carbohydrate ratio on energy expenditure and respiratory quotient (RQ) were assessed during 48-h respiration chamber measurements similar to 34 mo after weight loss. Participants consumed a high-protein (HP) diet In = 20; 13 women/7 men; age: 64.0 +/- 6.2 y; BMI: 28.9 +/- 4.0 kg/m(2)) with 25:45:30% or a moderate-protein (MP) diet (n = 18; 9 women/9 men; age: 65.1 +/- 5.8 y; BMI: 29.0 +/- 3.8 kg/m(2)) with 15:55:30% of energy from protein:carbohydrate:fat. Predicted resting energy expenditure (REEp) was calculated based on fat-free mass and fat mass. AT was assessed by subtracting measured resting energy expenditure (REE) from REEp. The main outcomes included differences in components of energy expenditure, substrate oxidation, and AT between groups. Results: EB (MP = 0.2 +/- 0.9 MJ/d; HP = -0.5 +/- 0.9 MJ/d) and RO (MP = 0.84 +/- 0.02; HP = 0.82 +/- 0.02) were reduced and REE (MP: 73 +/- 0.2 MJ/d compared with HP: 78 +/- 0.2 MJ/d) was increased in the HP group compared with the MP group (P <0.05). REE was not different from REEp in the HP group, whereas REE was lower than REEp in the MP group (P <0.05). Furthermore, EB was positively related to AT (r(s) = 0.74; P <0.001) and RQ (r(s) = 0.47; P <0.01) in the whole group of participants. Conclusions: In conclusion, an HP diet compared with an MP diet led to a negative EB and counteracted AT similar to 34 mo after weight loss, in participants with prediabetes in the postobese state. These results indicate the relevance of compliance to an increased protein/carbohydrate ratio for long-term weight maintenance after weight loss.
  • Coda, Rossana; Varis, Jutta; Verni, Michela; Rizzello, Carlo G.; Katina, Kati (2017)
    The effects of the substitution of wheat flour with faba bean flour and faba bean sourdough on the properties of composite bread were investigated. Bread was prepared by replacing wheat flour with 30% of faba bean flour, native or after sourdough fermentation. The addition of faba bean flour influenced the structure of the breads, causing a slight decrease of volume and higher hardness compared to wheat bread. However, when fermented faba bean flour was added, the crumb porosity of the bread was not affected. The addition of 30% of faba bean flour increased wheat bread protein content from 11.6 up to 16.5% of dry matter. The addition of native faba bean flour did not affect the in vitro protein digestibility, resulting similar to wheat bread (64%). On the contrary, faba bean sourdough bread showed higher protein digestibility (73%). Generally, the addition of native faba bean flour caused an improvement of the nutritional indexes of the composite bread, further enhanced when fermentation was carried out. The free amino acid profile, protein chemical score, and biological value index were the highest in faba bean sourdough bread. In addition, the predicted glycemic index was the lowest in faba bean sourdough bread. (C) 2017 Elsevier Ltd. All rights reserved.
  • Yoo, Bo Ram (Helsingfors universitet, 2017)
    Cardiovascular disease is one of the leading causes of mortality worldwide. Upon myocardial infarction, billions of cardiomyocytes are lost, a fibrotic scar forms, and the heart's contractile function is compromised. Mammalian cardiomyocytes lose most of their proliferative capacity shortly after birth. This decline in proliferative capacity is associated with a switch from glycolysis to oxidative phosphorylation, yielding more ATP, but also inevitably forming reactive oxygen species (ROS). Therefore, finding a way to extend the proliferative window seems crucial to cardiac repair. microRNAs (miRNAs) are short, single-stranded noncoding RNAs that repress gene expression after transcription by binding to their target mRNAs. SIRT1-7, mammalian homologs of the Sirt2 protein in yeast, have been implicated in the regulation of metabolic homeostasis, cell proliferation, cardiac hypertrophy, and aging. The objective of our research was to investigate the differential expression of SIRT1-7 between day 1 and day 7 neonatal mice. Since cells continue to divide until day 7, we wanted to compare the differences in sirtuin expression during the two time points. By doing so, we hoped to gain insight into ways we could regulate sirtuin protein expression by manipulating miRNA and sirtuin gene expression in diseased hearts, thereby promoting the fetal gene program and inducing cells to reenter the cell cycle. Proteins were isolated from whole cell lysates of cardiac tissue of day 1 and day 7 neonatal mice, and western blotting technique was used to analyze SIRT1-7 expression. Expression of SIRT3 and 7 was significantly higher in day 7 as opposed to day 1 in at least two of the three runs, with SIRT7 levels being higher in day 7 in all three runs. Our study provides a basis for carrying out more quantitative analysis to validate gene and protein expression and protein activity, since expression is different at the gene and protein levels and does not necessarily translate into activity.
  • Helminen, Pirjo (Helsingfors universitet, 2014)
    Thesis literature review deals with composition of cow´s milk, yogurt manufacturing, composition and process attributes affecting textural properties of yogurt and measuring textural properties of yogurt. Plain, stirred yogurts (kg) were manufactured at Valio Riihimäki and Oulu Dairies. The aim of the research was to find out attributes that affect yogurt quality. First milk base composition was determined and, yogurt textural properties were determined (viscosity, graininess, syneresis) using different techniques. Finally yogurt statistical relationships or Pearson correlations and statistical significance between yogurt textural properties and milk base composition and manufacturing process were determined. Additional objective was to determine common specification limits to yogurt textural properties. Statistical analysis; pearson correlation coefficients, p-value and specification limits were carried out using MINITAB®16 statistical software. Good yogurt texture is viscous, free from grains and syneresis. This study showed that yogurt textural properties (viscosity, graininess and syneresis) were affected significantly by yogurt manufacturing plant. There were a lot of fluctuations in yogurt textural properties. Consequently yogurt viscosity fluctuated over 50%, graininess approx. 25% and syneresis approx. 30%. According to this study, yogurts standing a long time before packaging, were less viscose or watery compared to those with shorter standing time prior to packaging. Graininess and evaporating process were found to correlate positively. Yogurts were with more grains when manufacturing process`s evaporating temperature and evaporating rate (l/h) were higher. The higher milk base fat and dry matter content (%) were found to correlate lesser whey separation in yogurt. In addition the higher evaporating rate was in the yogurt manufacturing process, the lesser whey separation was observed. Results from this research are useful for developing dairy processes concerning yogurt manufacturing.
  • Mercier, Léon (Helsingin yliopisto, 2018)
    PURPOSE AND GOALS Microalgae are unicellular eukaryotic organisms capable of photosynthesis. They harvest sunlight and efficiently take up carbon dioxide and nutrients such as nitrogen and phosphorus from their environment and use them for their growth. Due to these properties, their rapid growth and ability to survive in a variety of environments, microalgae have potential in biotechnological applications that promote nutrient recovery and recycling, water purification and the carbon neutral production of biochemicals and possibly biofuels. The purpose of this study was to investigate the suitability of a side stream water originating from the production of baker’s yeast (yeastwater) for the cultivation of a species of microalga called Euglena gracilis. The study aimed to determine the capacity of this water to support growth and protein production of E. gracilis as well as the capacity of E. gracilis to remove nutrients from the water. The effect of filtration of the water on these parameters was also studied. Yeastwater contains an organic molecule called betaine in relatively high concentrations. Betaine has previously been shown to boost the production of the important vitamin cobalamin in bacteria. The study aimed to determine the effect of betaine on the growth of E. gracilis and on the production of cobalamin in the algal-bacterial symbiosis. METHODS E. gracilis was cultured in laboratory scale photobioreactors. Its growth, protein production and nutrient uptake capacity was determined. Baker’s yeast production side stream water diluted with MQ-water was used as the growth medium either in filtered or unfiltered form. A control treatment was prepared where no microalgal inoculate was added to the photobioreactor. The same microalga was also grown in a synthetic nutrient medium with and without betaine. The uptake of betaine and biomass concentrations of cobalamin were determined. For the determination of microalgal growth, dry weight determination and flow cytometry analysis were used. Protein production was determined on the basis of total nitrogen concentration in the biomass. Spectrophotometric measuring kits were used for the determination of nutrient concentrations. Liquid chromatography techniques were used for the determination of betaine and cobalamin concentrations. RESULTS Significant microalgal growth was observed in filtered yeastwater, while growth in unfiltered yeastwater was very low. Nitrogen removal was higher in presence of E. gracilis compared to the control treatment. Protein production in yeastwater was comparable to that of microalgae grown in synthetic medium. E. gracilis grew much better in the synthetic media supplemented with betaine than without the addition. Betaine enrichment had no effect on cobalamin production. Cobalamin was produced in unfiltered yeastwater both with and without the presence of E. gracilis. CONCLUSIONS Unfiltered yeastwater does not support growth of E. gracilis possibly due to its high turbidity. Filtered yeastwater, on the other hand can support the production of E. gracilis biomass. E. gracilis can be used to reduce nitrogen concentrations in yeastwater. Yeastwater can support cobalamin production by bacteria, but this phenomenon did not benefit from the presence of the microalga. The effect of betaine on microalgal growth warrants further study to determine whether it is related to the accumulation of intracellular nutrients, storage compounds or to some other phenomenon. Yeastwater is a promising nutrient feedstock for microalgal biomass production. However, the role of filtration and possibility of using other methods for turbidity reduction needs to be further studied.
  • Kettunen, Oona; Heikkilä, Maria; Linnamo, Vesa; Ihalainen, Johanna K. (2021)
    The aim of this study was to provide information on energy availability (EA), macronutrient intake, nutritional periodization practices, and nutrition knowledge in young female cross-country skiers. A total of 19 skiers filled in weighted food and training logs before and during a training camp. Nutrition knowledge was assessed via a validated questionnaire. EA was optimal in 11% of athletes at home (mean 33.7 +/- 9.6 kcal center dot kgFFM(-1)center dot d(-1)) and in 42% at camp (mean 40.3 +/- 17.3 kcal center dot kgFFM(-1)center dot d(-1)). Most athletes (74%) failed to meet recommendations for carbohydrate intake at home (mean 5.0 +/- 1.2 g center dot kg(-1)center dot d(-1)) and 63% failed to do so at camp (mean 7.1 +/- 1.6 g center dot kg(-1)center dot d(-1)). The lower threshold of the pre-exercise carbohydrate recommendations was met by 58% and 89% of athletes while percentages were 26% and 89% within 1 h after exercise, at home and at camp, respectively. None of the athletes met the recommendations within 4 h after exercise. Nutrition knowledge was associated with EA at home (r = 0.52, p = 0.023), and with daily carbohydrate intake at home (r = 0.62, p = 0.005) and at camp (r = 0.52, p = 0.023). Carbohydrate intake within 1 and 4 h post-exercise at home was associated with better nutrition knowledge (r = 0.65, p = 0.003; r = 0.53, p = 0.019, respectively). In conclusion, young female cross-county skiers had difficulties meeting recommendations for optimal EA and carbohydrate intake. Better nutrition knowledge may help young athletes to meet these recommendations.
  • Perkiö, Pasi (Helsingfors universitet, 2013)
    The aim of the literature review was to examine barley’s (Hordeum vulgare) alcohol-soluble proteins – hordeins and their technological attributes. Additionally, applicability of flow field flow fractionation (FFF) separation method as well as spectrophotometric and light scattering methods for protein characterization was under investigation. The objective of the experimental research was to determine a suitable extraction method for hordeins and subsequent analysis of their molecular weight distribution, size and conformation by the use of AF4 (asymmetric flow field flow fractionation) in combination with MALS-, UV- and RI-detectors. 40 % 1 propanol combined with mild sonication treatment proved to be the most efficient method to extract hordeins from barley flour. In order to prevent deterioration of the FFF channels the solvent had to be diluted to 20 %. Same dilution was used to measure hordeins’ extinction coefficient and to calculate ?n/?c theoretically. Berry plot was found to be the most suitable fit for the data analysis. Extracted hordeins were analysed with SDS PAGE. Extracts contained monomeric C, B and ? hordeins and polymeric B, D and ? hordeins. Also, small amounts of albumins, globulins and hydrolysed proteins were present. Extracts’ fractograms had five distinctive peaks. All of the peaks’ mass fractals and polydispersity indices were above 1, which means analysed aggregates were polydisperse and shaped as complex rods. This can be explained by 1 propanol influenced protein aggregation. Some inference in light scattering was identified in the MALS detector signal. This and the use of measured extinction coefficient and calculated index of refraction caused some errors in the data. The low sample yield (19–26 %) can be explained by the hordeins’ adhering to a syringe filter and adsorbing to the surface of AF4’s ultrafiltration membrane. Also, the use of over simplifying mathematical model to calculate the results and yield could cause some errors in the results. This study showed that it is possible to study Mw, size and conformation of polymeric hordeins with AF4 combined with MALS/UV-detectors and that hordeins form big aggregates in 20 % 1 propanol. For MALS proteins should be extracted in a solvent that will not interfere with subsequent analysis and proteins net charge, which creates a challenge to find proper solvent for hordeins. Nevertheless AF4 proved to be useful and delicate tool for characterizing cereal polymeric proteins.
  • Lius, Elina (Helsingin yliopisto, 2019)
    Finding new plant-based protein sources is important from a sustainable development perspective. Ethanol and starch production from barley results in fiber and protein side-stream fractions that are currently utilized for animal feed. Nonetheless, it would be more profitable if the barley protein side-stream was used as a human food ingredient. The main storage proteins in barley are known as hordeins. They are polymeric proteins and have low solubility, due to their inter-chain and inter-molecular disulfide bridges and hydrophobic side-chains. In food technology applications protein solubility is an important property for emulsifying and foaming functionality. Proteins are sensitive to the surrounding environment, especially to pH, which could be used to alter the solubility. In this thesis the literature review examined barley (Hordeum vulgare) proteins, especially the hordeins, functionality and effect on food materials. The review includes previous studies concerning cereal proteins functionality in general and their effect on food materials and a discussion on protein stabilized emulsions. The aim of the study was to determine the protein composition of two barley protein concentrates, OP1 and OP2, and to evaluate protein solubility and emulsifying properties. Furthermore, the aim of the study was to compare the functionality of the concentrates. According to SDS gel electrophoresis the protein concentrates consisted mostly of hordeins, especially C-hordein and some B-hordein. Minor amounts of other proteins where also identified. The protein solubility was determined by Lowry’s method. The proteins were more soluble in sodium phosphate buffer than in deionized water. In sodium phosphate buffer at pH 3,8 the solubility of OP1 proteins was 100 mg/g ± 11 mg/g and in deionized water at pH 3,9 the solubility was 45 mg/g ± 1,1 mg/g. The solubility of the OP2 proteins in sodium phosphate buffer at pH 3,8 was 47 mg/g ± 1,5 mg/g and in deionized water at pH 3,7 the solubility was 45 mg/g ± 1,1 mg/g. In both samples the proteins solubility increased as the pH increased. Most proteins were solubilized at pH 11: the solubility for OP1 and OP2 proteins were 240 mg/g ± 11 mg/g and 140 mg/g ± 12 mg/g respectively, which is problematic regarding food products, but could be used as a treatment to improve solubility. The smallest oil droplets were formed in emulsions were the pH was adjusted to 7 with sodium phosphate buffer. The stability of emulsions was however poor in all samples because of phase separation, which was already significant after one day of storage. The phase separation was considered to be flocculation which finally resulted in creaming or sedimentation. The flocculation may have occurred due to hydrophobic interactions between the proteins on the oil/water interface. However, shaking of the emulsion causes the flocculated oil droplets to separate, forming an even emulsion. No coalescence was observed in all samples, except for OP1-emulsions with 1 % (w/v) dry matter. These results confirm that these protein concentrates can be used in food products, especially in milk type drinks that need to be shaken before usage.
  • Liu, Chang (Helsingfors universitet, 2015)
    The literature review related to faba bean proteins, the mechanism of protein oxidation and detection methods for protein oxidation as well as the relationship between lipid and protein oxidation. Native faba bean, faba bean treated by oven and microwave, as well as soy protein isolate were used as materials. The materials differed in their lipoxygenase activity. Oil-in-water emulsions were made of 10% purified (removal of antioxidants) rapeseed oil and 3% water soluble proteins that were extracted from flour samples. The emulsions were prepared by homogenizing using microfludizer. Oxidation took place in the oven at 37 °C in the dark with constant stirring by magnet stirrers. Sampling for measurements was carried out on day 0, 1, 4 and 7 from each replicate. Oxidative stability of was monitored by following lipid oxidation as formation of conjugated dienes and hexanal, and by following protein oxidation by measuring loss of tryptophan, formation of carbonyls and dityrosine through fluorescence detections both in the lipid phase and in the continuous phase. In this study, the degree of protein oxidation was generally consistent with corresponding lipid oxidation. Generally, the degree of protein oxidation in lipid phase of emulsions was higher than that in continuous phase, although the protein content was far less in the lipid phase. Both results implied co-oxidative relationship between lipid and protein oxidation. In addition, the results showed that thermal treatment or microwave irradiation can not only result in retarding or decreasing lipid oxidation by lowing lipoxygenase (LOX) activity, but also affect protein oxidation via lipid oxidation and the conformational changes of proteins.
  • Kolu, Anna-Maija (Helsingfors universitet, 2013)
    Spray drying is one way to dry protein medicines and it has many advantages compared to other drying methods, for example it is a fast process. In spray drying high temperature and mechanical stress can inactivate the protein. Disaccharides are generally used as protective agents of protein in spray drying because they have an ability to protect the structure of the protein during drying and storage. Aim of this research was to study the stability of the protein during spray drying and storage by using β-galactosidace as a model protein. Aim was also to characterize the physical properties of trehalose and melibiose and to study how well they protect the protein. Some of the central matters to be examined were the glass transition temperature, crystallinity, water activity, yield of the spray dried powder and protein activity. Especially studying the properties of melibiose in spray drying was important because it has not been used before. The study also included the optimization of the process parameters to be suitable for the product. Trehalose and melibiose transformed to an amorphous form during spray drying. Both XRPD and DSC showed an amorfous form. Trehalose and melibiose proved to be good protective agents for the protein during spray drying and storatge probably because they remained their amorphous structure. β-galactosidase remained activity very well. Optimizing of the process parameters was successful because protein remained its activity and still the powder was quite dry and yield was good. The changes in the structure of the protein were studied with FT-IR but the amount of the protein was too small. Problems caused by the spray drier may have an effect to the results, but on the other hand the spray dryer was made to work optimally.
  • Ketonen, Krista (Helsingfors universitet, 2014)
    Variation of the protein and amino acid content of barley, wheat and oats were studied. Diets based on grain samples of different protein content were optimized for pigs and poultry.The study went on to optimize diets for pigs and poultry with grains of different protein contents. The amino acid and raw protein analysis was undertaken on 38 grain samples. Correlations were calculated between different variables in grain samples and linear regression analysis was conducted between the protein and amino acid composition. The best estimate for amino acid concentrations of cereals was the protein content. The relative content of amino acids decreases as protein content increases and especially so in barley and wheat. Most reliable regression equations between amino acid and protein content were made for barley and wheat samples. For oat reliable regression equations could not be made. Oats also differed by other features from barley and wheat as it correlated with different variables compared to barley and wheat. Amount of needed protein concentrate levels decreased when barley and wheat protein and amino acid contents were considered in optimization. Protein concentrate levels did not decrease when used oat sample with highest protein content.
  • Paivarinta, Essi; Itkonen, Suvi T.; Pellinen, Tiina; Lehtovirta, Mikko; Erkkola, Maijaliisa; Pajari, Anne-Maria (2020)
    Increased consumption of plant-based foods and decreased consumption of animal-based foods is recommended for healthy diets and sustainable food production. We investigated the effects of partial replacement of dietary animal proteins with plant-based ones on intake of energy-yielding nutrients, fibre, and plasma lipoproteins. This 12-week randomised clinical intervention comprised 107 women and 29 men (20-69 years) in three diet groups with different dietary protein compositions ("ANIMAL": Animal 70%/plant 30%; "50/50": Animal 50%/plant 50%; "PLANT": Animal 30%/plant 70%; all: Protein intake 17 E%). Nutrient intakes were assessed by 4-day food records. Saturated fat intake (E%) was lower and polyunsaturated fatty acid intake (E%) higher in the PLANT and 50/50 groups compared to the ANIMAL group (p <0.001 for all). Fibre intake was higher in the PLANT (p ? 0.001) and 50/50 (p = 0.012) groups. Total and LDL cholesterol were lower in the PLANT than in the ANIMAL group (p = 0.003 for both) but no differences in HDL cholesterol or triglycerides were observed (p > 0.05). Replacing animal protein with plant protein sources in the diet led to an increased fibre intake and improved dietary fat quality as well as blood lipoprotein profile. Flexitarian diets could provide healthy and more sustainable alternatives for the current, predominantly animal-based diets.