Browsing by Subject "Food Technology (Cereal technology)"

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  • Heikkilä, Pirketta (Helsingfors universitet, 2011)
    The focus of the literature review of the study was on ice cream, different kinds of coatings used in the food industry and coating methods. In addition, the typical combosition of chocolate, rheological properties of liquid chocolate and the interaction between the consistency and rheological properties were reviewed. The objective of the study was to find out how consistency and coating temperature affects viscosity, yield value, solidification time and the amount of the coating layer in ice cream stick. The idea was primarily to find out how the amount of the coating layer could be controlled. Variables selected in this study were the amount of fat and emulsifiers in the milk chocolate coating and the coating temperature. The amount of coating layer, solidification time of the coating and viscosities and yield values of liquid coating were measured. The xperiment was planned using a Box-Behnken design. Results were calculated with regression analysis. Response surface methodology was used to estimate how the changes in fat amount, emulsifier amount and temperature affected the amount, solidification time, viscosity and yield value of coating. Increasing the amount of fat significantly decreased the amount, solidification time, viscosity and yield value of the coating. Increasing the amount of emulsifier decreased the amount, solidification time and yield value of the coating. Increasing temperature of the coating decreased the amount and viscosity of the coating, but increased solidification time of the coating. From the results, temperature, fat content and emulsifier content of the coating were found to affect the amount of the milk chocolate coating layer on an ice cream stick. Response surface methodology foud to be suitable method for investigating the amount of chocolate coating. Methods to control the amount of coating layer were examined by means of response surface methodology.
  • Luoto, Sanna (Helsingfors universitet, 2011)
    The literature review dealt with celiac-toxic Triticeae prolamins and their enzymatic degradation. Also the immunochemical methods for prolamin analysis were introduced. The gluten-derived immunogenic peptides are proline-rich and thereby remarkably resistant to proteolytic degradation. Most of the triggering prolamins can, however, be degraded by combining endogenous cereal enzyme activity with acidic incubation. Despite of this residual prolamins still exist and their concentration exceeds the threshold considered to be safe for gluten intolerants. The objective of the experimental work was to further hydrolyse the residual prolamins present in malt autolysates of wheat, barley and rye, with a food grade proline endopeptidase from Aspergillus niger (AN-PEP). Size-exclusion chromatography (SEC), free amino nitrogen (FAN) and SDS-PAGE analysis determined the extent of protein hydrolysis. Actual prolamin degradation was observed with immunological methods. Hydrolysis of residual prolamins was extensive in all malt systems – more than 96% of the prolamins were hydrolysed. The SEC and FAN data revealed that continuation of the hydrolysis overnight converted the polypeptides into smaller hydrolysis products. According to enzyme-linked immunosorbent assay analyses, 22 h incubation decreased the prolamin contents of wheat and rye malt hydrolysates below the level of 100 mg/kg. This level was achieved with AN-PEP concentration of 35 ?L/g in relation to freeze-dried autolysate. According to the Codex Alimentarius, food products containing gluten up to 100 mg/kg can be labelled 'very low gluten' and thus included in coeliac diet. AN-PEP treated rye malt ingredient could especially be a promising low-gluten ingredient to enhance the flavour of often poor-quality gluten-free bread. Before commercial applications can be devised the potential as a flavouring agent as well as the clinical safety of the product must be evaluated.
  • Wanhalinna, Viivi (Helsingfors universitet, 2010)
    In this master´s thesis the quantity of the greenhouse gas (GHG) emissions produced by food supply chain was studied. Also results from life cycle studies related to GHG emissions of bread, flour and some other food material were collected. In the experimental study the carbon footprints (GHG emissions, CO2 equivalents) of wheat and rye breads were calculated. Industrial scale production, Finnish grown wheat and rye, and simplified bread recipes were used as starting points. The life cycle calculations included cultivation, milling and baking phases and also consumer´s action. The amounts of GHG emissions for these phases were obtained from previous studies and the information reported by food enterprises and organizations. The cultivation of wheat and rye were studied separately, but the milling and baking processes were considered similar. The data were collected from two mills and seven bakeries and included details from energy and water consumption and the amount of organic waste and waste water produced. The emissions associated with the production of salt, baker´s yeast, vegetable fat, sugar and packaging material were also included. For consumer´s, there were two scenarios, one included transportation of bread from grocery by car, and 10 % wastage. The other included also toasting of the bread. It was calculated that the carbon footprint of bread was 1400-1500 g of CO2-equivalents/ kg bread. The cultivation´s share was 40 %, the mill´s share was 2 %, the bakery´s share was 45 % and the consumer´s share was 13 %. When the toasting of bread was included, this action alone resulted approximately 180 g more GHG emissions. There was a small difference between the carbon footprint of rye and wheat bread. The difference results mainly from differences in recipes of breads. There are not yet uniform standards to calculate the carbon footprint. Therefore a lot of generalizations and assumptions had to be made in the calculations. Nonetheless the carbon footprint obtained in this study is of the same magnitude as recently obtained in other studies performed in Europe.
  • Meskanen, Marko (Helsingfors universitet, 2013)
    Most barley is used for animal feed or malting. However, barley contains technologically and nutritionally valuable components. The compositions of different barley cultivars as well as the factors affecting the concentrations of different nutrients (beta-glucan, protein, starch and ash) were surveyed in the literature part of this Master’s thesis. Special attention was paid to beta-glucan as it has attained significant interest in the food industry due to its positive health effects. In addition, the effect of grain composition on the pearling, milling and air classification properties of barley were surveyed. The nutrient composition and milling properties of ten different barley varieties were examined in the experimental part of the thesis. The varieties were divided into four subgroups based on their potential end usage: 1) speciality barley, 2) feed barley, and 3) starch barley, and 4) malting barley. The milling properties were analysed by sieve analysis and volumetric particle size distribution from the whole grain barley flours. In addition, coarse fractions were separated from the whole grain flour by air classification. These fractions were also analysed by the abovementioned particle analyses. Beta-glucan, protein and ash concentrations were usually higher in the speciality barley varieties and their coarse fractions. Starch concentrations were lower in these varieties and fractions. Feed and starch barleys had somewhat higher beta-glucan concentration compared to malting barleys, which respectively had the highest starch concentrations. Zero to 25 % of the grain’s outer layers was removed by pearling. Compositional analyses revealed that pearling decreased the amount of ash and increased the concentration of starch and betaglucan until about 15 % of the grain was pearled off. Starch and beta-glucan concentrations did not change significantly after this pearling level. Pearled barley flour was manufactured by pearling off 15–20 % of the grain’s outer layers, and milling the remaining pearled grains with a fine impact mill. Flour was then air classified to give fine and coarse fractions. The coarse fractions contained enriched concentrations of beta-glucan, protein and ash. However, their concentrations and yields were dependent on the speed of the classifier wheel. By contrast, starch was enriched in the fine fractions. The highest beta-glucan concentration was obtained with the beta-glucan-rich speciality variety D, which initially had 9.4 % beta-glucan. The beta-glucan concentration was enriched up to 11.4 % by pearling. Air classification of whole grain flour resulted maximally in 13.5 % and air classification of pearled grain flour in 15.5 % beta-glucan concentration. Based on the results, the beta-glucan concentration of the raw material seems to play the most important role in the enrichment. However, proper milling technology and air classifier settings are of utmost importance.
  • 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.
  • Arte, Elisa (Helsingfors universitet, 2013)
    The literature review focused on the composition of the barley hordeins and the known extraction methods. The metal-catalysed oxidation of proteins and amino acids was also reviewed. The aim of the experimental part was to develop a simple selective extraction method for the B and C hordeins and to study how metal-catalysed oxidation affects these hordeins. Hulles barley cf. Jorma was selected as test material since milling of this cultivar was simple with a Brabender Junior mill. From the milled barley, water and salt-soluble material were removed and the rest was freeze-dried. The freeze-dried sample flour was studied by gel separation, precipitation and extraction with aqueous alcohols. The aqueous alcohol extracted the C hordeins completely although there was some B hordeins present. Two-dimensional electrophoresis showed that the isoelectric point of C hordeins was between the pH 5–7. Aqueous alcohols, extraction temperatures and pH were studied for hordein extraction. None of the studied methods improved the extraction of B and C hordeins. The hordein sample used in further experiments was extracted with 55% 2-propanol at 50 ºC. The metal-catalysed oxidation of the extracted hordeins was studied by using copper or iron as a catalyst and hydrogen peroxide or ascorbic acid as an oxidant. The reactions were analysed with SDS-PAGE and SE-HPLC. The results showed that the most effective reaction was with copper and hydrogen peroxide where the B and C hordeins were degraded efficiently after 24 hours of incubation. The results from SE-HPLC showed aggregated B hordeins in the extracted sample, which were partly degraded after two hours of incubation with hydrogen peroxide and copper. The results of this study indicated that the biggest groups of hordeins, the B and C hordeins, cannot be selectively separated with extraction. The barley hordeins efficiently degraded in the metal-catalysed oxidation with hydrogen peroxide and copper.
  • Männistö, Laura (Helsingfors universitet, 2012)
    The literature review focused on the basic structure and characteristics of the cereal starches such as the structure of the starch granule, chemical composition and gelatinization properties. Properties of starches from different botanical sources were compared. The objective of the experimental study was to compare the characteristics of native barley starch to other cereal starches and especially to potato starch. Native commercial barley starch was used as testing material which has uniform size distribution (A). This barley starch was compared to commercial wheat, corn and potato starches. Gelatinization properties were measured by RVA (Rapid Visco Analyzer) in acidity range from 3 to 6. Starch granules were observed by light-microscopy. Viscoelastic properties of starch gels were measured reometrically and texture analyzer was used for surface properties. Synersis as diffused amount of liquid was measured of starch gels. Suitability of barley starch in sponge cakes was also investigated. The effect of pH was significant on gelatinization of starches. The maximum viscosity of cereal starches increased when pH decreased, at the same conditions the viscosity of potato starch decreased. The maximum viscosity of potato starch was nearly ten times higher compared to cereal starches. Native cereal starches formed harder gel and during the storage syneresis was stronger than in the potato starch. The potato starch gel was sticky and bright in color. Sponge cake made of potato starch had the highest level of retrogradation and its volume was small. Potato starch may not be applied to confectionary, because it made the crumb structure dry faster than cereal starches. The sponge cake made of corn or potato starch was firmer in crumb structure. Barley starch was more suitable for sponge cake than corn or potato starch. The size distribution of starch granules seemed to have an impact on stability of cake dough. Barley starch was different in many properties compared to potato starch and those applications differ from each other. Based on this research barley starch is suitable for cake baking.
  • Rahikainen, Antti (Helsingfors universitet, 2013)
    The aim of the literature review was to research barley proteins, metal-catalyzed oxidation and subjects related to it, like antioxidants and oxidation reactions in beer. In addition ACE inhibition was looked into. The object of the experimental part was to find out if the proteins of a barley-based industrial side product can be modified by metal-catalyzed oxidation or enzymatic hydrolysis, and how these treatments affect the different proteins in the sample material. In addition, the possible ACE inhibition activity of the reaction products was determined. The sample material was a protein-rich side-product of barley starch production. Two protein fractions were extracted from the material; an alcohol soluble fraction and a reduced fraction. The modification of the proteins in the sample fractions by oxidation and hydrolysis was determined with gel electrophoresis and size exclusion chromatography. The ACE inhibitory activity of the small peptides from these reactions was determined with UV-VIS spectroscopy. Three protein groups were identified from the sample material; polymeric B hordein, monomeric B hordein and C hordein. Contrary to expectations metal-catalyzed oxidation did not break down any of the proteins in the sample; instead it aggregated the proteins into bigger units. The enzyme treatment hydrolyzed the proteins effectively. Small peptides from the enzyme hydrolysis had an ACE inhibition IC50 of 246 µg/ml, which is similar to gluten hydrolysates IC50 of 29 µg/ml. IC50 is the inhibitor concentration where 50% of enzyme activity is inhibited. Instead of breaking down the subject proteins metal-catalyzed oxidation aggregated them, and thus it could not be used to make ACE inhibitory peptides. Enzyme hydrolysis was found to be a valid method of inhibitor peptide production. The peptides produced had an ACE inhibition capacity similar to previously known ACE inhibitory food hydrolysates.
  • Laine, Juhana (Helsingfors universitet, 2011)
    The literature review focused on the composition of oats along with wheat-free oat baking technology. Enzyme active baking and rye malt utilization in low gluten baking was also reviewed. In the experimental part the effect of an extract prepared from rye malt sourdough on dough viscosity and oat bread quality was studied in order to develop technology to good quality rye flavored oat bread. Rye malt flour of high enzyme activity was used to prepare a sourdough enabling degradation of rye prolamins, harmful to celiac patients. Rye malt extract was prepared from the sourdough by centrifugation. Part of the extract was heated for enzyme inactivation to compare the effects of the enzyme active and inactive extracts on oat dough and bread. The extract was used for baking 15, 25 and 30 % (dough weight) by reducing water. Miniature size breads (20 g) were baked in small pans. Dough viscosity was measured to show partial hydrolyzation of beta-glucan due to enzyme activity. Rye flavor was measured with the help of trained jury. Rye malt extract decreased dough pH approximately from 5.8 to 4.4 and increased the titratable acidity. The dough was less viscous when using enzyme active extract and more viscous when using the inactivated extract. The rye malt extract increased bread firmness and flavor and aroma were improved. Also the pores in the crumb were smaller and more evenly distributed. The inactivated extract increased bread crumbliness. The results suggest that the production of good quality rye flavored oat bread is technologically possible when using an enzyme active extract. This can possibly be explained by the low pH inhibiting the amylases together with high gelatinization temperature of oat starch. During fermentation, the pH of the rye malt sourdough drops so low that it inhibits the excessive ?-amylase activity in the dough so that excessive starch hydrolysation cannot occur. Therefore the use of the rye malt extract in baking process is possible without inactivation. Sourdough fermentation as part of gluten-free baking can improve bread color, aroma, flavor and texture. Also, the addition of rye malt extract improved mold-free time by lowering the pH. It seems that with the help of this technology it is possible to add long yearned rye flavor to low gluten oat bread. Based on earlier results it was concluded that it is possible to achieve bread prolamin content of 63.5 mg/kg. However, it should be possible to obtain even better results with the help of further development.