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Study of the presence of phenolic substances and their antioxidant activity in food products containing rosehip (Rosa canina L.)
Hronová, Vendula ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor's thesis monitored the content of bioactive substances and antioxidant activity in the jams made of the fruit of rose hips (Rosa canina L.). The jams were sweetened with various sweeteners such as cane sugar, beet sugar, erythritol and stevia. Moreover, the rheological properties of jams were determined. The properties of home-made jams prepared from rosehip fruit were compared with the commercial jam. Another aim was to determine whether the by-products received after the production of jams could serve as beneficial sources of bioactive substances after the preparation of water extracts. The content of carbohydrates, polyphenols, flavonoids, and antioxidant activity were determined in jams and extracts spectrophotometrically. Next, the spectrophotometric detection of pectin, the chemical characterization of jams by infrared spectrometry, and the spectrophotometric determination of the jam colour were performed. The concentration of bioactive substances in jams was influenced by the geographical location and the time and weather conditions of harvest. The rheological properties and pectin content of the jams depended on the type of the used sweetener. The assessment of the water extracts prepared from the by-products after jam production and from the dried fruits of rosehip showed the high content of bioactive substances and high antioxidant activity in all tested extracts. The presented work points out that it is possible to prepare jams with superfood properties from the fruit of rose hips and extracts with high antioxidant activity.
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Monitoring of fatty acids content during cheese production
Rajnochová, Veronika ; Mikulíková, Renata (referee) ; Vítová, Eva (advisor)
This master thesis deals with the monitoring of fatty acids during production of natural Edam cheeses, i.e. natural hard cheeses with low heat curd, and of processed cheeses, which were produced from them. The theoretical part briefly characterizes the natural Edam cheese and processed cheese, the main attention is paid to lipids, fatty acids and the possibility of their determination. In the experimental part the content of fatty acids in the model samples of natural and processed cheese produced at Tomas Bata University in Zlín was determined. The method according to ISO 1735 was chosen for extraction of lipids from the samples, the method according to ISO 5509 using methanol solution of potassium hydroxide was chosen for the esterification of fatty acids. The resulting methyl esters were determined by gas chromatography with FID detection.
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The effect of the quantity and type of nuts used in the production of pâté on the product sensory quality
Mejzlíková, Blanka ; Kovalčík, Adriána (referee) ; Mikulíková, Renata (advisor)
This bachelor thesis deals with the sensory evaluation of pâté with nuts. The 9 samples of pâtés which contained different quantity of nuts and different types of nuts were produced for sensory evaluation. In the theoretical part pâtés are characterised, their history, composition and manufacturing are described. The part of literature search is description and chemical composition of nuts which were used for production of pâtés. Another topic is a description of conditionals and methods of sensory analysis and sensory evaluation of meat products. The practical part comprises production of test samples, samples for sensory analysis, evaluating the heat treatment and sensory analysis. Percentage amount of lipids and composition of fatty acids were determined by gas chromatography. Processing of results of sensory and chemical analysis of samples of pâtés was determined that the best samples were pâtés with cashew nuts and pistachios.
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Utilization of waste banana peels for packaging materials
Vachta, Jonáš ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis deals with isolation of cellulose from waste banana peels and it’s use as a filler in composite films. The aim of this work was to prepare a bioplastic capable of being an eco-friendly alternative to conventional polymers with a potential for application in the packaging industry. The cellulose was isolated from banana peels using a method combination of alkalic and acidic hydrolysis and bleaching by sodium chlorite. The samples after isolation were characterised by Fourier transform infrared spectroscopy (FT-IR) and their average particle size was determined by microscope observation. Subsequently, composite films were prepared using agar and starch matrix, glycerol as plasticizer and isolated cellulose as filler in various concentrations to assess the effect of added cellulose on the properties of the resulting bioplastics. Characterization of the prepared bioplastics included FT-IR measurement, surface examination by a scanning electron microscope (SEM) and the determination of mechanical properties by measuring tensile strength, elongation at break and Young’s modulus. It was found that the addition of cellulose from banana peels has a positive effect on the mechanical properties of all prepared agar- or strach-based composites, with the exception of elongation at break in agar films, where there was a slight decrease compared to the reference films.
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Effects of the addition of fortified wine in the production of pates on the sensory quality of the product
Kmeť, Jan ; Slavíková, Zuzana (referee) ; Mikulíková, Renata (advisor)
The aim of this thesis is to evaluate effect of addition of fortified wine on sensory quality of pâté. Thesis deals with preparation of fortified wine enriched pâté and their suitability for consumption. Main ingreditents, mainly meat and fortified wine are described in theoretical part. Furthermore, the technology of pâté production, methods and conditions of sensory analysis are also listed in this thesis. A total of nine types of pâté were prepared, eight of these pâtés contained different amouts of selected fortified wines. By evaluation of thermosterilation process, prepared pâtés were suitable for consumption. The sensory analysis showed us that addition of fortified wine mailny affects appearence, colour and flavour of product. Most preffered were pâtés without addition of fortified wine. Pâtés that contained Santa Cruz pink porto Rosé wine and Czech liqour wine Agni were well rated.
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Dependence of quality parameters of malt on the temperature of mashing at sweet wort preparation
Zlámalová, Petra ; Sachambula, Lenka (referee) ; Mikulíková, Renata (advisor)
The Masters thesis deals with dependence of quality parameters of malt on the temperature of mashing at sweet wort preparation. The theoretical part focuses on the technology of malt production including description of ingredients, production parts, some kinds of malt and the quality parameters. There is also described the technology of sweet wort preparation and the methods of determination of the malt quality parameters in the sweet wort there. The experimental part focuses on determination of malt extract, viscosity, haze, colour, time of starch cleavage, pH, degree of fermentation and beta-glucans content. Based on temperature dependence of parameters, the individual samples were compared and the effects of temperature were discussed. The biggest extract of light and caramel malts was explored at 70 °C, of coloured malt at 50 °C. The lowest viscosity of light and coloured malts was explored at 65 °C, of caramel malt at 50 °C. The lowest haze of wort was at 65 °C. Ideal colour of all malts was at all mashing temperatures. Ideal pH of all malts was explored at 70 °C. Ideal time of starch cleavage was explored at 70-85 °C. The biggest achievable degree of fermentation and the hugest increase of beta-glucans content were explored at 65 °C.
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Modification of soda lignin isolated from winery waste
Chovanec, Martin ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis provides research on the antibacterial activity of lignin isolated from grape pomace. To separate lignin from grape pomace was used soda lignin isolation method. This method helps to dissolve lignin in the solution of sodium hydroxide. Two isolation procedures were used: 1) isolation by using a conventional laboratory set-up at atmospheric pressure and a temperature of 110 °C and 2) isolation by using a hydrothermal autoclave at increased pressure and a temperature of 110 °C. The hydrothermal autoclave was explicitly developed for this bachelor thesis. Both separations methods were compared from the viewpoint of lignin yields and lignin purity. The lignin yield obtained by using the hydrothermal autoclave was much higher compared to the conventional laboratory set-up, yielding about 36.4 g of soda lignin per 100 g of grape pomace. The infrared spectroscopy analysis of both lignins showed that lignin received by using the conventional laboratory set-up was mixed with hemicelluloses and cellulose. The isolation by using the hydrothermal autoclave enabled to prepare lignin with higher purity. Lignin isolated from grape pomace did not show any antimicrobial activity. The antimicrobial activity was reached after modification of lignin with silver particles in situ. Antimicrobial activity was tested against Bacillus subtilis, Escherichia coli, Micrococcus luteus, Serratia marcescens, Saccharomyces cerevisiae and Candida glabrata. The lignin/silver compound showed the antibacterial activity against all tested bacteria, however no antimicrobial activity against yeasts.
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Analysis of sensorially active substances contained herbal extracts
Koloničná, Markéta ; Vítová, Eva (referee) ; Mikulíková, Renata (advisor)
The peppermint (Mentha piperita), the salvia (Salvia officinalis), the lemon balm (Melissa oficinalis), the camomile (Matricaria chamomilla) and the valerian (Valeriana officinalis) are herbs with healing effects. Their ethanol extracts are used for food fortification or in a cosmetic industry. Substances contained in herbal extracts were analyzed in this thesis. The extracts were prepared by maceration. Next, they were analyzed by using a gas chromatography and a mass spectrometry. The aim of this thesis was an optimalization of the method used for the analysis of sensorially active substances. Then, herbal extracts were analyzed and concentration of sensorially active substances was determined.
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Multirezidual analysis of selected pesticides in barley
Ehrenbergerová, Martina ; Duroňová, Kateřina (referee) ; Mikulíková, Renata (advisor)
Barley is one of the economically important crops. Its production is primarilly used as fodder barley and also in brewery and food industry. Particularly the part of its production intended for malt production must be of high quality. There are some important factors which can influence the quality of the crops, such as harmful organisms – diseases, pests and weed. In order to regulate the occurence of harmful organisms, agricultural measures are taken in the integrated protection system and resistant variants and pesticides are used. The higher the demand on the production quality, the bigger is the volume and the spectrum of pesticides used. The increasing extent of pesticide use also poses a risk for internal production quality and the environment. This fact makes it necessary to monitor unfavourable influences, including the contents of the pesticide residues in barley. This work studies the possibility of multiresidual determination of some selected pesticides in malting barley.
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Optimalization of SPME for assessment of volatile sulphur compounds in malt and beer
Mišovie, Zuzana ; Vespalcová, Milena (referee) ; Mikulíková, Renata (advisor)
Volatile sulphur substances originating during technological processes in malt and beer production can be a cause of various off-flavors and aromas. Their precursors are sulphur-containing amino acids. Sulphur substances play an important role in brewing as even in very low concentrations they can negatively affect total character of beer. Therefore, it is necessary to monitor volatile sulphur substances and their precursors to eliminate undesirable processes. Because sulphur substances occur in beer and raw materials at trace levels, microanalytical methods are used for their detection. This diploma thesis describes the problems of sulphur substances and their determination using the SPME/GC method.
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