Browsing by Subject "Elintarviketieteiden maisteriohjelma"

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  • Helander, Riina (Helsingin yliopisto, 2019)
    Ruokaturvallisuuden merkitys korostuu tulevaisuudessa muun muassa ilmastonmuutoksen, kuluttajan toiveiden ja globalisaation myötä. Ammattikeittiöissä ruokaturvallisuus painottuu elintarvikehygieniaan ja sitä toteutetaan omavalvonnalla. Omavalvonnan kirjauksia, kuten lämpötilahallintaa, on perinteisesti tehty käsin paperille ja valvonnan mittaukset ovat olleet näytemittauksia jatkuvan valvonnan sijasta. Suomalaisissa ammattikeittiöissä omavalvonta toteutuu pääasiassa hyvin, mutta lainsäädännön tulkinta, resursointi ja epäyhtenäiset toimintatavat saattavat aiheuttaa haasteita. Ihmisen rooli ruokaturvallisuudessa on merkittävä. Tänä päivänä teknologian hyödyntäminen ruokaturvallisuudessa yleistyy ja uusia innovaatioita siihen kehitetään jatkuvasti. Omavalvonta voidaan digitalisoida ja automatisoida. Tämän tutkimuksen tavoitteena oli kehittää digitaalista omavalvonnan palvelua ruokaturvallisuutta edistävästi. Tutkimus oli laadullinen tutkimus, jossa menetelminä käytettiin puolistrukturoitua teemahaastattelua ja lyhyempää kyselyhaastattelua. Teemahaastattelujen haastateltavat olivat ammattikeittiöiden keittiöpäälliköitä tai ylemmän tason esimiehiä ja kyselyhaastatteluihin vastasi keittiöiden työntekijät ja kokit. Lisäksi haastateltiin neljää valvontaviranomaista. Teemahaastattelun teemoja olivat omavalvonnan merkitys, haasteet ja ajankäyttö, digitaalisen omavalvonnan vahvuudet, heikkoudet ja kehittäminen, palveluntarjoajan rooli sekä digitaalisen omavalvonnan vaikutus ruokaturvallisuuteen. Valvontaviranomaisilla teemana oli myös valvontakäynnit. Nauhoitetut aineistot litteroitiin ja analysoitiin sisällönanalyysilla teemoitellen. Haasteita omavalvonnassa tuottivat resursointi, lainsäädännön tulkinta sekä eri tasoinen osaaminen niin ruokaturvallisuudesta kuin digitaalisista työvälineistä. Digitaalinen omavalvonta lisäsi haastateltavien mielestä ruokaturvallisuutta automaattisen lämpötilaseurannan, läpinäkyvyyden ja sitouttamisen myötä. Digitaalista omavalvontaa tulisi kehittää kahdesta näkökulmasta. Ensinnäkin, digitaalisten työvälineiden tulisi ohjata käyttäjää tekemään ruokaturvallisia ratkaisuja, perehdyttää, motivoida ja sitä kautta sitouttaa paremmin omavalvonnan tekemiseen. Toiseksi, teknologian ratkaisuja ja automatisointia tulisi lisätä laajemmin koko omavalvontaan. Eri keittiöiden eri prosessit ja sitä kautta omavalvonnan toimintamallit tulee huomioida kehityksessä.
  • Haajanen, Hanna (Helsingin yliopisto, 2020)
    3-Chloro-1,2-propanediol (3-MCPD), 2-chloro-1,3-propanediol (2-MCPD) and 2,3-epoxy-1-propanol (glycidol) and their fatty acid esters are contaminants formed during processing fat containing foodstuffs at high temperatures. Mainly MCPD and glycidyl esters have been found to be formed in the deodorization process of oils, and in vegetable oils, such as palm oil, they have been measured at high concentrations. In accordance with the restrictions imposed by the European Commission, the levels of glycidyl esters must be especially monitored, as they have been identified as potentially carcinogenic compounds. The aim of the study was to introduce and validate a gas chromatographic analysis method for glycidyl esters and MCPD esters for the Customs Laboratory. The method was validated for two matrices: first for oils and then for powdered infant formulas. In addition, the success of the validation was examined by analyzing various oil samples previously received by the Customs Laboratory. The Customs Laboratory is also involved in the activities of the European Union Reference Laboratory, for which it was intended to participate in the reference measurement organized by the EU Reference Laboratory. The method for the determination of 3-MCPD, 2-MCPD and glycidyl esters in oils and infant formulas was carried out according to the guidelines of the European Union Reference Laboratory for Contaminants (EURL-PC). Determination of MCPD and glycidyl ester concentrations in oils and infant formulas included the following steps: fat extraction by liquid-liquid extraction (for infant formulas), addition of standards, solid-phase extraction, conversion of glycidyl esters to 3-MBPD esters, transesterification, neutralization, salting out, derivatization and analysis with gas chromatography-mass spectrometry system. Concentrations were determined using internal standard method. The method was validated for the following parameters: specificity, selectivity, limit of detection and quantitation, reproducibility, repeatability, trueness, linearity and working range, stability and measurement uncertainty. The analytical method developed for the determination of MCPD and glycidyl esters was successfully validated for oils and powdered infant formulas. The developed method proved to be specific and selective. The limit of determination was found to be 6.3 µg/kg, 1.3 µg/kg and 0.8 µg/kg for the oil matrix 3-MCPD, 2-MCPD and glycidyl esters. The limits of determination for the infant formula were 5.4 µg/kg, 3.0 µg/kg and 1.6 µg/kg for 3-MCPD, 2-MCPD and glycidyl esters. Recoveries for MCPD and glycidyl esters in the oil and powdered infant formulas were 83-105%. R2 for calibration lines were greater than 0.99, and the lines were linear over the entire measurement range of 2-1000 µg/kg. The relative standard deviation of repeatability and reproducibility was less than 20% for both matrices. The expanded measurement uncertainty for the MCPD and glycidyl esters of the oil and powdered infant formula was less than 50%. For all parameters, the requirements set by the Customs Laboratory and the performance requirements of Regulation (EU) 1881/2006 were met. A method validated for two matrices can then be accredited. The customs laboratory may use the developed method in the future to control 3-MCPD, 2-MCPD and glycidyl esters levels of oils and powdered infant formulas. In the future, the method could also be validated for new matrices, such as liquid infant formulas.
  • Tuccillo, Fabio (Helsingin yliopisto, 2021)
    As the number of vegetarians and flexitarians is increasing, the demand for meat alternatives is following the same trend. Faba bean is a promising crop for environmental, health, and social reasons. From its seeds, several products can be produced, such as flour, protein concentrate, and protein isolate. These materials can be further processed for the development of texturized vegetable proteins. In this context, high moisture extrusion (HME) is an innovative technology, which requires more water, but milder temperatures than the more studied low moisture extrusion. The present thesis aimed at covering the current knowledge gap on this technology, by focusing on the flavor aspect of faba bean-based meat alternatives. The volatile profile of faba bean flour, protein concentrate, protein isolate, and mixtures was studied before and after high moisture extrusion by means of HS-SPME-GC-MS. Comparisons were made between raw materials (flour, protein concentrate, protein isolate, mixtures) and extrudates. The effect of the origin (Canadian and Finnish) of the protein concentrate was also investigated. Materials were also characterized for the following aspects: moisture, ash, protein, lipids, lipid-degrading enzymes (lipase and lipoxygenase), free amino acids, and free mono-, di-, and oligosaccharides. Several classes of volatile compounds were observed in both raw materials and extrudates, namely organic acids, alcohols, aldehydes, alkanes, alkenes, aromatic compounds, furans, esters, ketones, nitro compounds, and terpenes. Many compounds were characteristic of only one material, demonstrating that the formation of certain volatiles was product dependent. However, some other compounds were found in all materials, such as 1-hexanol, hexanal, and 2-pentylfuran. Literature addresses these compounds as responsible for the beany flavor. HME caused the inactivation of lipase and lipoxygenase but did not prevent the formation of lipid oxidation products. Products from Maillard reaction were not found in the extrudates. After HME, 1-hexanol levels decreased, whereas the abundance of 2-pentylfuran significantly increased. The behavior of hexanal after HME was less stable and predictable than the two beforementioned compounds. Not only these novel findings could have application in product development, but they also laid the basis for further research aimed at improving the flavor of faba bean.
  • Tukia, Nea (Helsingin yliopisto, 2021)
    The objective of the research was to compare collagen characteristics, general meat quality parameters and carcass characteristics of three different muscles from freely pasturing Mangalitza Red breed and highly bred domestic/commercial pig breed. Collagen content and collagen solubility was analyzed by hydrolyzing the three different muscle samples. Meat quality parameters were analyzed previously by Natural Resources Center (Luke). The pH of Mangalitza LD muscle varied from 5.41 to 5.64, SM muscle from 5.53 to 5.75 and IS muscle from 5.74 to 5.87, IS having higher pH than the two other muscles (P < 0.05). The pH of commercial pig LD muscle varied from 5.47 to 5.75, SM muscle from 5.52 to 5.77, and IS muscle from pH 5.96 to 6.51, IS having higher pH than the two other muscles (P < 0.05). Breed had effect on pH of muscle IS (P < 0.05), but no effect on muscles LD or SM (P > 0.05). The color of muscles of Mangalitza was darker than commercial pig’s in all the three muscles (P< 0.05). In Mangalitza, LD was lighter than SM and IS, but in commercial pigs, LD and SM were lighter than IS (P < 0.05) Collagen content of all three muscles of Mangalitza differed from each other (P < 0.05) and the collagen content of LD and SM were lower (P < 0.05) than of commercial pig’s collagen content. In commercial pig, collagen content of LD and SM muscles were lower than in IS muscle (P < 0.05). Collagen solubility of all three muscles of Mangalitza differed from each other (P < 0.05) and the collagen solubility of SM and IS were lower (P < 0.05) than of commercial pig’s collagen solubility. In commercial pig, collagen solubility of LD and SM muscles were lower than in IS muscle (P < 0.05). In contrast to collagen content, collagen solubility of LD muscles did not differ between the breeds (P > 0.05). The amount and solubility of collagen did not deviate from normal; it can be concluded that this study did not provide any new information other than the collagen content and solubility of Mangalitza Red breeds muscles of LD and SM.
  • Ylipoti, Kerttu-Maaria (Helsingin yliopisto, 2020)
    Take away food has increased in popularity in the past years. However, there are not many cardboard-based take away packaging options for restauranteurs. Plastic materials such as expanded polystyrene are most commonly used for take away packaging, but the single-use plastics directive by the European Commission has added polystyrene as one of the materials to be banned by 2021. Additionally, consumers are also becoming more educated on material sustainability, which brings added pressure and opportunity for developing new alternatives to the market. This case study implemented customer-dominant logic (CDL) to the design process of a cardboard-based take away package. In CDL, value-creation is perceived as a personal, subjective and holistic process, where the customer is in the center of the value formation process. The aim was to create a CDL based design framework and test whether it resulted in a cardboard-based take away package which created value for the consumer. The case study also aimed to uncover the factors of take away packaging which contributed to the value creation for customers. The results were collected through three consumer studies, which used qualitative methods such as responsive interviews and the Value Toolkit®. It was concluded that cardboard as a material was seen as renewable and easy-to-recycle. The cardboard-based package was successfully designed, as it was rated highest in comparison to a polystyrene-based package and a compostable bagasse package in the final consumer study. It was discovered that out of the four value types: performance, experience, status value, and responsibility, consumers thought performance was the most important in take away packaging. The CDL based framework for package design was successful. The framework can further be studied with collateral case studies, where one design team uses the CDL based framework and the other uses a more traditional approach to design.
  • Kazerani Garcia, Afsane Aurora (Helsingin yliopisto, 2021)
    Non-communicable diseases such as cardiovascular diseases (CVDs) and erosive, unsustainable industrial fat-production methods pose two of the biggest threats to human health in great part of our planet. CVDs and obesity have been linked to diets high in fat and low in dietary fibre, pushing food manufacturers to adapt to more sustainable ingredients. For this reason, this research developed and researched about a new and sustainable plant-based oleogel intended to act as a substitute for saturated and hydrogenated fats. Its characterization was conducted through several techniques, including optical and field emission electron scanning microscopy, differential scanning calorimetry, Fourier transmission infrared spectroscopy, and synchrotron X-ray powder diffraction. The results showed that the build-up of the formation of the new oleogel was possible, while ensuring that both processing requirements and ingredients are readily available at food manufacturing plants, globally. These findings pose a great opportunity for plant-based fat-replacement formulations, through a sustainable approach. Considering previous studies, this novel system could potentially help in reducing the burden of obesity and CVDs, turning it into a functional food component. Further research on food applications and digestibility models could give more insight on the future applications of this fat-replacement system.
  • Kalmu, Niina (Helsingin yliopisto, 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.
  • Kinnunen, Eveliina (Helsingin yliopisto, 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.
  • Astola, Anni (Helsingin yliopisto, 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.
  • Niklander, Katariina (Helsingin yliopisto, 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.
  • Kang, Jingran (Helsingin yliopisto, 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.
  • Rissanen, Janina (Helsingin yliopisto, 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.
  • Laitinen, Miikka (Helsingin yliopisto, 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.
  • Kantanen, Katja (Helsingin yliopisto, 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.
  • Sammalisto, Saara (Helsingin yliopisto, 2019)
    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.
  • Tikkanen, Pinja (Helsingin yliopisto, 2021)
    Tutkimuksen tarkoituksena oli kartoittaa optimaalinen hydrokolloidiyhdistelmä, joka parantaa gluteenittoman leivän rakennetta ja tuoreena säilymistä. Hypoteesina oli, että löytyisi tietty kahden hydrokolloidin yhdistelmä koesuunnitelmaa käyttämällä. Tutkimuksessa käytettiin kolmea eri hydrokolloidia ja niiden määrät vaihtelivat kolmella eri tasolla. Hydrokolloidien vesiliuosten reologisia ominaisuuksia tutkittiin viskositeetti- ja oskillaatiomittauksilla. Leivistä mitattiin tilavuus, rakenne ja rakenteen säilyminen seitsemän vuorokauden säilytyksessä ja raskista mitattiin pH ja happoluku. Leivistä tehtiin myös aistinvarainen asiantuntija-arviointi. Raskien pH-arvojen keskiarvo oli 4,49 ±0,01 ja happoluvun keskiarvo 12,9 ±0,2. Hydrokolloidien vesiliuosseosten, GM + MNS1 ja GM + MNS2, viskositeettien mittauksissa virtauskäyrissä ei ollut eroa mutta GM:n (galaktomannaanista muodostunut kasvikumi, joka on peräisin palkokasvista) viskositeetti oli selvästi matalampi kuin seosten. Oskillaatiomittauksessa GM:n huomattiin myös erottuvan seoksista huomattavan paljon pienemmällä viskositeetilla sekä varasto- ja häviömoduulilla. GM muodostaa yksin ollessaan heikon geelirakenteen, mutta seoksilla on vahvempi geelirakenne. Modde-ohjelmiston vastepintaohjelman avulla saaduista tuloksista voitiin nähdä vain kimmoisuuden ja joustavuuden mallintuvan yhden päivän säilytyksen jälkeen. Tehtyjen analyysien perusteella päivä leivonnan jälkeen modifioitu neutraali selluloosa 1 (MNS1) ja modifioitu neutraali selluloosa 2 (MNS2) paransivat leivän joustavuutta. MNS2 lisäsi myös leipien kimmoisuutta, kun taas MNS1:llä ei ollut vaikutusta ja GM pienensi leipien kimmoisuutta. Myös seitsemännen säilytyspäivän jälkeen MNS1 piti leivän rakennetta joustavampana muihin saman ikäisiin leipiin verrattuna. Käytetyillä hydrokolloideilla ei ollut tilastollista eroa leivän kovuudessa, pureskeltavuudessa eikä murtumisherkkyydessä. Selkeitä eroja leivissä näkyi aistinvaraisesti arvioituna vain huokosjakaumassa. Huokosjakaumalta epätasaisimpia olivat leivät, joissa oli käytetty MNS1 tai MNS2 tasolla 3. Leipien säilönnän aikana oli kuitenkin huomattavissa selkeää kuivumista ja kovettumista. Leivonnasta seitsemännen päivän kohdalla lähes kaikki leivät olivat todella kovia ja sisus oli kuiva. Leipien maku oli myös heikentynyt aiempiin päiviin verrattuna. Tutkittujen hydrokolloidien vaikutusta leivän pehmeyteen ja nautittavuuteen ei voida todentaa tehtyjen tutkimusten perusteella, aistinvaraisesti arvioituna leivät eivät olleet selkeästi pehmeämpiä hydrokolloidilisäysten myötä.
  • Aaltonen, Saara-Sofia (Helsingin yliopisto, 2021)
    The beneficial nutritional quality of oats and the recognition as a naturally gluten-free grain has increased its popularity. In the baking of wholemeal oat bread, the absence of gluten complicates the handling of the dough, and the oat cultivars differ in their baking quality a lot. For now, test baking is the only way to optimize whole oat baking. The aim of this study was to define how oat cultivars differ in their baking quality and how to adjust the dough yield for optimal baking result. The hypothesis was that oat varieties grown in different fields bake differently and by optimizing the dough consistency with dough yield, baking result can be improved. The work examined three oat cultivars and a total of five oat flour samples in the baking of palabread i.e. flat, yeast proofed bread. Moisture content, beta-glucan, and protein contents, pasting curves, particle sizes of flour and water binding were determined from the samples according to standard methods. All flour samples were baked first with dough yield of 215. The consistencies of doughs were measured with backward extrusion method by Texture Analyzer device. Based on the oat bread that proved to be the best in test baking, the optimal level of consistency was determined, to which dough yields were adjusted for the following baking tests. Breads baked with dough yields of 215 and breads obtained from optimized consistencies were compared sensorially and bread staling was measured by the hardness of the crumb for three days after baking. Oat cultivars differed in beta-glucan and protein contents. High beta-glucan and protein content of oat flour resulted in higher water-binding capacity and higher dough consistency. The low water-binding capacity of oat flour was associated with greater drying of the breads and faster aging. Moisture was bound better to the bread when the water-binding capacity of the oat was higher. The consistencies of the dough varieties of oat cultivars differed significantly with the same dough result, and the consistencies obtained from different flour samples of the same cultivars also differed from each other. There were no major sensory differences in the oat breads of the study, but breads baked from different oat flours differed in hardness and aging rates, even though the breads were baked with the same dough consistencies. The optimization of the consistency evened out the quality differences between the oat samples and improved the work-ability of the dough. The optimization was found to be successful in modifying handling of the dough and the structure of the baked bread in desired direction.
  • Päivärinta, Katariina (Helsingin yliopisto, 2019)
    Hajuammattilaisuudella, hajuharjoittelulla ja muulla systemaattisella hajuille altistumisella on merkittävää vaikutusta hajuaistin toimintaan. Muutokset näkyvät esimerkiksi hajuaistin herkkyydessä sekä kyvyissä havainnoida, tunnistaa ja erottaa hajuja toisistaan. Tämän maisterintutkielman tavoitteena oli selvittää eroavatko aistinvaraisen arvioinnin ammattilaiset ja elintarviketieteiden opiskelijat toisistaan hajujen tunnistamisen, kokemisen ja ruokamieltymyksien suhteen. Tutkimuksen hypoteesien mukaan ammattilaiset olisivat parempia tunnistamaan hajuja, kuvailisivat niitä useammilla sanoilla ja arvioisivat ne keskimäärin tutummiksi sekä heillä olisi vähemmän ruokainhokkeja. Lisätavoitteena tutkimuksessa oli myös tarkastella mahdollisia hajunäytteiden välisiä eroja. Tutkimuksen merkityksenä oli olla osa aistinvaraista perustutkimusta ja tuottaa uutta tietoa vähän tutkitun hajuammattilaisten alatyypin, elintarvikkeiden aistinvaraisen arvioinnin ammattilaisten, hajuaistikyvyistä. Tutkimukseen osallistui yhteensä 85 koehenkilöä, joista aistinvaraisen arvioinnin ammattilaisia oli 23 kpl, elintarviketieteiden opiskelijoita 56 kpl ja muiden alojen opiskelijoita tai työntekijöitä 6 kpl. Tutkimus koostui kolmesta osasta, jotka olivat hajujen tunnistustesti, hajunäytteiden arviointitehtävä sekä verkkokysely. Hajujen tunnistustestissä koehenkilöiden hajuaisti testattiin 32 hajun Sniffin’ Sticks-tunnistustestillä. Hajunäytteiden arviointitehtävässä näytteitä oli 6 kpl (β-jononi, tyrni, L-karvoni, valkosipuli, D-karvoni, balsamico) ja niistä tutkittiin koettua miellyttävyyttä, voimakkuutta, tuttuutta ja laatua. Verkkokyselyllä kartoitettiin koehenkilöiden ruoka-asenteita ja suhtautumisia erilaisiin ruokalajeihin ja ainesosiin. Tutkimuksessa havaittiin ammattilaisten olevan parempia tunnistamaan hajuja ja kuvailevan niitä useammilla sanoilla kuin opiskelijat. Ammattilaiset eivät kuitenkaan arvioineet hajuja keskimääräisesti tutummiksi eikä heillä ollut tilastollisesti merkitsevästi vähemmän ruokainhokkeja. Hajunäytteiden keskinäisessä vertailussa havaittiin eroja hajujen välillä. Miellyttävimmäksi arvioitu β-jononi oli myös hajuista vähiten tuttu ja voimakas. Voimakkaimmaksi ja epämiellyttävimmäksi arvioitiin balsamico, kun taas tutuin haju oli valkosipuli.
  • Nikander, Vertti (Helsingin yliopisto, 2021)
    Mixed culture beer contains additional microbes in addition to brewing yeast, Saccharomyces cerevisiae. Typical microbes found in mixed culture beer are lactic acid bacteria and other yeast species than S. cerevisiae. Mixed culture beers are usually sour so they can be also called sour beers. They also contain a very small number of hops. German Berliner Weisse and Belgian Lambic are traditional mixed culture beers. Craft beer has made mixed culture beers more popular. This has led to development of new kinds of mixed culture beers. The goal of this study is to establish, can alternative souring microbe be used in brewing. This study wanted to establish does the microbe grow in beer, what kind of substances it produces and how does it affect the sensorial qualities of beer. The study was executed by making two identical beers, which the other was inoculated with the souring microbe and yeast and the other with only yeast. CFU/ml of the souring microbe and yeast was determined by plating. In addition, the most vital carbohydrates, organic acids and the ethanol content together with volatile compounds was determined by liquid and gas chromatography respectively. Samples were taken a duration of three months after which there was a sensory evaluation with a trained panel. Based on the results the souring microbe is suitable for brewing. It grew in beer during fermentation and after bottling. Based on the sensory evaluation, beer containing the souring microbe did not differ considerably compared to beer containing only yeast. It was evaluated to be very similar in measured attributes in the sensory evaluation. The biggest difference between specified substances were in organic acids only found in beer containing the souring microbe. Also, beer containing the souring microbe had deviation in maltose and ethanol content possibly because of contamination. Differences between volatile compounds were small in the two beers respectively. More study is needed to optimise the fermentation process and improve the sensorial qualities with more sensorial study.
  • Sainio, Taru (Helsingin yliopisto, 2019)
    Availability of plant-based food products and snack products has increased during the last years. In Finland, especially oat-based food products have been popular. Milk-based yogurts have been accompanied by fermented oat-based snack products, ‘oatgurts’. The aim of this study was to investigate texture and mouthfeel properties of commercial oatgurts and milk-based yogurts. Pleasantness of the mouthfeel and overall pleasantness were also studied. In addition, structure properties of the products were measured with instrumental methods. Sensory study of the products was conducted as a consumer study (n = 87) using a time-dependent method called Temporal Dominance of Sensations, TDS. TDS was used to study dominant sensations of mouthfeel properties (creamy, foamy, thick, thin, sticky and watery) during eating. Two milk-based yogurts with 2,5 % and 4,0 % of fat and five oat-based gurts were used as samples. Overall pleasantness and pleasantness of the mouthfeel were evaluated with a 7-point hedonic scale. Assessor’s demographic factors, innovativeness and usage frequency of plant-based yogurts were studied with the sensory study. With instrumental methods viscosities during steady state shear rates 10 s-1 and 50 s-1 were measured. In addition, flow curves, amplitude sweeps, frequency sweeps were conducted, and particle sizes of the products were measured. According to the results, milk-based products were scored more pleasant in the overall pleasantness and in the mouthfeel pleasantness. However, one of the gurts was statistically as pleasant in the mouthfeel as the milk-based yogurt with lower fat content (2,5 % of fat). Ethnic background of the assessors had an impact to the hedonic ratings of the gurts. Assessors with Finnish background (n = 68) evaluated the gurts more pleasant in the overall pleasantness and in the pleasantness of the mouthfeel. Innovativeness of the assessors had an impact to the overall pleasantness of the gurts but not to the pleasantness of the mouthfeel. According to TDS results, creaminess and thickness improved the hedonic ratings whereas wateriness and thinness had a negative effect on the hedonic ratings. According to the instrumental measurements, structures of the products were different. One of the gurts showed rheopectic behavior which is less common among food products. Other products were thixotropic. From the results it can be concluded that high viscosity of the products correlated positively with dominance ratings of thickness. To find reliable connections between sensory properties and instrumental measurements, more research must be done. There were differences in the mouthfeel properties of the milk- and oat-based products. Oatgurts and their mouthfeel properties have lot to be improved that their pleasantness would be equal to milk-based yogurts. In a future research, it would be good idea to find out what kind of qualities consumers want for oatgurts and whether milk-based yogurts are good reference products for oatgurts.