|
|
Application of profile test on several types of foods
Přerovská, Mariya ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This diploma thesis was focused on the use of profile tests for sensory analysis of foods. The development of profile methods, advantages and disadvantages of the techniques, specific training of panelists, the organization and the requirements for testing place and testing is described in theoretical part. There is a brief overview of other methods and legislation used in sensory analysis. In the experimental part of this work several types of foods such as bread, ham, yogurt, apple and chocolate have been selected. For each of these foods the forms for profile evaluation of flavor and texture have been developed. Consequently, the selected samples were sensorially evaluated by panel composed from students of FCH BUT.
|
|
|
Determination of alergenic and potential alergenic metals in cosmetics
Krakovková, Lenka ; Zemanová, Jana (referee) ; Diviš, Pavel (advisor)
The aim of the diploma thesis was to provide an overview of the prevalence of allergenic and potentially allergenic metals in eye shadows. The diploma thesis gives an overview of the legislation on cosmetics and description of the types of allergenic reactions caused by allergenic and potential allergenic metals in eye shadows. Listed below are the preparation methods of the samples for analysis and the list of the methods by which can the selected metals be analyzed. The experimental part of the diploma thesis deals with an analysis of selected allergenic and potentially allergenic metals in eye shadows. In the experimental part of diploma thesis method of sample preparation for analysis of eye shadows and a method of analysis of sample of eye shadows by ICP-MS have been optimized. Monitored analytes were selected metals. Altogether 6 samples of eye shadows from different manufacturers were chosen. Measured results have been statistically processed, confronted with the applicable legislation and assessed in terms of possible allergic reactions.
|
|
|
Representation of selected elements in human hair
Jochimová, Eva ; Janoušková, Eva (referee) ; Zemanová, Jana (advisor)
Hair is an excellent matrix for monitoring trace elements and minerals in the body. To long-term changes in concentration of elements in the body are reflected in their value in her hair, so the assessment of the organism from the mineral analysis of hair is a very suitable method. This method is widely used in toxicological testing and forensics. This work deals with the analysis of Mg, K, Fe, Zn, Mn, Se, As, Cd and Pb in 100 samples by ICP-MS. It is a male hair samples with the age range 19 – 74 years. Analysis of hair revealed that concentrations of individual elements are moving in a narrow range of values. Values of older age category are in some case significantly deflective.
|
|
|
Analysis of selected allergens in fragrances
Koláčková, Adéla ; Janoušková, Eva (referee) ; Zemanová, Jana (advisor)
This thesis is focused on potentially allergenic substances (PASs) in cosmetics. Their specific features, methods of control and observation are described. There are also mentioned dermatology problems connected with usage of perfumed cosmetic products in which the allergenic ingredients can be found and possibilities of their regulation. Fragrances are mixtures of natural or synthetic character which give the aroma. In nature, fragrances are produced mainly by plants. More than one hundred fragrances have been identified as allergens. Twenty six of them were declared as PASs. Allergenic components of perfume compositions are the main cause of allergic contact dermatitis. Experimental part of the thesis is focused on the procedure of analysis of specific allergenic fragrances (?-Amylcinnamaldehyde, Anisealcohol, Benzylsalicylate, Cinnamaldehyde, ?-Hexylcinnamaldehyde, 7-Hydroxycitronellal and Methyl-2-octynoate). Headspace-Solid Phase Microextraction connected with Gas Chromatography-Flame Ionisation Detector (HS-SPME-GC-FID) was used for extraction, analysis and identification of these substances. The method was validated and applied on the spectrum of real samples of cosmetic products.
|
|
|
Thermo-oxidative stability of mixtures of vegetable oils
Kovačíková, Barbora ; Lehocký,, Marián (referee) ; Zemanová, Jana (advisor)
Rostlinné oleje se používají v mnoha odvětvích chemického průmyslu. V průběhu zpracování konkrétního produktu, ve kterém jsou rostlinné oleje použity, dochází často ke zvyšování teploty. Vyšší teplota urychluje průběh auto-oxidace což negativně ovlivňuje stabilitu olejů nebo výrobků z nich připravených. Mezidruhové mísení olejů je poměrně častým jevem jak při samotné výrobě tak i ve finálním výrobku. Cílem této práce bylo stanovit termo-oxidační stabilitu šesti čistých rostlinných olejů a jejich binárních směsí. První část práce zkoumá oleje a připravené směsi pomocí metody diferenciální kompenzační kalorimetrie. Tato metoda umožnila pochopení vztahů mezi termo-oxidačním chováním olejů a jejich směsmi pomocí stanovení teplot degradace. Přímá souvislost mezi obsahem mastných kyselin a stabilitou byla prokázána pouze zčásti, stejně tak jako původní předpoklad, že přídavek stabilnějšího olej zvýší stabilitu oleje méně stabilního. V několika případech docházelo dokonce ke snížení stability pod teplotu degradace obou čistých olejů. Ve druhé části byl zjišťován mechanismus pro-oxidační fáze vedoucí k degradaci olejů pomocí termogravimetrie, která ukázala přírůstek hmotnosti ve vzorcích oleje způsobeného absorpcí kyslíku a tvorbou peroxidů předcházející degradaci. V tomto případě již bylo možné pozorovat jistou souvislost mezi obsahem mastných kyselin a vzrůstem hmotnosti, pouze však jen pro čisté oleje. Ani v tomto případě nebyla prokázána aditivita vlastností způsobujících stabilitu směsí rostlinných olejů.
|
|
|
Evaluation of stability of selected vegetable oils
Němečková, Lenka ; Lehocký,, Marián (referee) ; Zemanová, Jana (advisor)
This diploma thesis is focused on issues concerning the stability of selected vegetable oils which are used in cosmetic industry. The stability of eight oils without additives were determined by a differential scanning calorimeter. In the first phase, the temperatures of oil degradation were determined for different rates of heating, i.e. nonisothermal stabilities. They were consequetly used to calculate isothermal stabilities alias induction periods. The calculation of induction periods was completed by using integral isoconversional methods, which applied four different temperature functions. One of the temperature functions corresponded to Arrhenius equation while the others to non-Arrhenius functions. The confrontation of induction periods under standart conditions showed that an optimal temperature function to calculate oil stabilities is one of the non-Arrhenius functions in exponential form. We can state that all oils are degraded by similar, if not the same, mechanism. The specified stabilities, in periods of months, have proved the importance of using stabilizers and other additives in the commercial and technological use of vegetable oils.
|
|
|
Diurnal changes of Rubisco content and its activity under ambient and elevated concentrations of carbon dioxide
Matulková, Zuzana ; Zemanová, Jana (referee) ; Hrstka, Miroslav (advisor)
In this diploma thesis, the diurnal changes of initial and total Rubisco activity and Rubisco enzyme content in beech (Fagus sylvatica) were studied under conditions of ambient (A) CO2 concentration (350 µmol.mol-1) and elevated (E) CO2 concentration (700 µmol.mol-1) during the day. Samples were taken on July 8th (from 10:00 to 21:30), on July 9th (from 04:00 to 12:00) and then on July 22th (from 04:00 to 21:30). The initial and total activity were measured spectrophotometrically and the activation level was calculated from the ratio of initial and total activities. Rubisco enzyme content was determined by SDS-PAGE method and the initial and total specific activity were calculated from the ratio of initial or total activity and Rubisco enzyme content. In our experiment no statistically significant difference was found between Rubisco activities in beeches cultivated under conditions of ambient CO2 concentration and elevated CO2 concentration, so any down-regulation of Rubisco activity did not appear under the influence of ambient CO2 concentration. Diurnal changes of Rubisco activities showed only statistically nonsignificant fluctuation. After daylight no significant increase of total Rubisco activity was observed, which demonstrates the absence or the immaterial effect of CA1P night inhibitor in beech. Intensive fluctuation of the activation level (40–90 %) proves the regulation of photosynthesis during the day via Rubisco enzyme carbamylation. Rubisco enzyme content in beech cultivated under conditions of ambient CO2 concentration was lower than that one in beech cultivated under conditions of elevated CO2 concentration. Then down-regulation of Rubisco enzyme content is presented under conditions of ambient CO2 concentration. Before daylight Rubisco enzyme content showed an indistinctive minimum on the level of statistical significance, during the day only nonrelevant fluctuation was noticed.
|
|
|
Evaluation of applicability of indirect photometric detection for chiral separations of selected carboxylic acids in dairy products
Dvořák, Miloš ; Zemanová, Jana (referee) ; Vespalcová, Milena (advisor)
In this diploma work is check possibility application indirect photometric detection for enantiomers separation lactic acids and beta-hydroxybutyric acid with capillary electrophoresis. As chiral selector is used vankomycin. Verifyed his ability partial separation lactic acid on antipode with using picric acid as vizualition anion in background electrolyte. Used was coated capillary. Application indirect photometric detection succeed. Chiral separation beta-hydroxybutyric acid wasn't successful. Hip roll by selection fit vizualization anions for purposes indirect photometric detection. Are measured their electrophoretic and spectrophotometric characteristics, for inquest compatibility use in capillary electrophoresis in relation to indirect photometric detection. From timed datums were to be you - nap optimal vizualizatin anions for others experimentation. According to ascertained and measured feature reflect be optimal eosine soluble in alcohol and bromophenol blue.
|
|
|
Evaluation of selected dietary supplements - climacterium
Tobolková, Blanka ; Vránová, Dana (referee) ; Zemanová, Jana (advisor)
A dietary supplement is a product that contains nutrients (e.g. vitamins, minerals, herbs, amino acids or fatty acids) intended to supplement the diet. The aim of the diploma thesis was to suggest a prescription for preparation of three types of dietary supplements which are used to reduce of climacteric symptoms, their production and determination of energetic (nutrition) value on account of detected content of proteins, fats and saccharides in dietary supplements. A part of the diploma thesis was to suggest suitable wrapping and price of prepared dietary supplements. The three dietary supplements were used for analyses, namely capsules, herb syrup and herb drops. The content of proteins was determined by Kjeldahl´s method, total fats were determined by Soxhlet extraction and saccharides were determined by titration with potassium permanganate (Bertrand´s method). Dietary supplements in form of capsules were particular analysed on content of heavy metals (lead, cadmium and arsenal). In herbal drops was in addition determined alcohol content (ethanol). There was from the measured data found out, dietary supplement in form of capsules was chosen as the product with the lowest energetic (nutrition) value.
|
|
|
Study of preservative systems for cosmetics
Šmétková, Zuzana ; Vítová, Eva (referee) ; Zemanová, Jana (advisor)
The aim of this diploma thesis was to prove the antimicrobial actvivity of the selected syntetic preservatives used in cosmetics, such as methylparaben, butylparaben, phenoxyethanol, bronopol, imidazolidinyl urea and methylisothaizolinone, in different concentrations (up to the highest permitted concentration and in increased concentrations), and of some essential oils, which are possible to use in cosmetics (essential oil from Eucalyptus globulus, Pimpinella anisum, Lavandula officinalis, Rosmarinus officinalis, Foeniculum vulgare, Mentha piperita, Juniperus communis and Pinus sylvestris). The effect was investigated in every preservative system alone, in order to evaluate the spectrum and the rate of each one. As indicator microorganism was chosen Bacillus subtilis and Penicillium chrysogenum. The used methods was disk difusion method and modify difusion method. From synthetic preservatives had the best effects bronopol, imidazolidinyl urea and methylisothiazolinone. From chosen natural antimicrobails had the effect against both indicator microorganisms the Mentha piperita, Foeniculum vulgare and Juniperus communis extracts.
|
guest ::
