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Characterisation of elderberry fruits
Christovová, Silvia ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
This master's thesis deals with the characterization of elderberry fruit (Sambucus nigra L.) with emphasis on the aroma active compounds (AAC) and vitamin C (ascorbic acid (AA), dehydroascorbic acid (DHA)). The theoretical part gives a brief outlook on the chemical composition and attributes of Sambucus berries, its healing properties and the means of processing. The rest of the theoretical part thoroughly examines the AAC and vitamin C. The suitable assessment methods are also discussed. The experimental part of the work consists of two main tasks. The first one was to assess the aroma profile of Sambucus berries using the HS-SPME-GC-FID. 18 samples were examined (the wild elderberry and 17 cultivated varieties). In total, 24 different volatile aroma active compounds were identified and quantified, 12 of which belonged to alcohols, 5 to aldehydes, 4 to esters, 1 to acids and 2 “other” compounds (linalool and -damascenone). The chemical composition of the individual samples was not uniform; no single sample contained all of the identified compounds. The second task was to assess the total vitamin C content (the sum of DHA and AA) using the HPLC. For the purpose of reducing DHA to AA three reducing agents were examined (DTT, TCEP and L-cysteine) at two different pH levels (7 and 4). TCEP at pH 4 turned out to be most efficient and was subsequently applied on the samples of 5 selected elderberry varieties. The measured vitamin C content was within the range of 5,1 – 13,0 mg per 100 g of fruit.
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Determination of sweeteners and preservatives in energy drinks by HPLC
Zídková, Anežka ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This master´s thesis is focused on simultaneous determination of sweeteners and preservatives in energy drinks by liquid chromatography coupled with DAD and ELSD detection. The method was optimized for determination of aspartame, acesulfame K, saccharin, sucralose, steviol glycosides, benzoic acid and sorbic acid. Analyses were carried out on the Poroshell 120 EC-C18 column (4.6 x 150 mm, 2.7 m, Agilent) using mixture of methanol, acetone and water with formic acid and trimethylamine as a gradient mobile phase at a flow rate 0,5 mL•min-1. Validation parameters were determined (limit of detection, limit of quantification, repeatability and recovery). The validated method was applied on real samples.
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Analysis of mycotoxins in barley and malt
Čuta, Robert ; Obruča, Stanislav (referee) ; Běláková, Sylvie (advisor)
This bachelor´s thesis deals with the mycotoxines present in cereals, especially in barley and malt. Teoretical part summarizes the knowledge of mycotoxines and their occurrence. The possibilities of mycotoxines determination are held forth in this thesis. In the experimental part an ultrasonic extraction metod of deoxynivalenol was optimized. For the deoxynivalenol determination was used a method of high-performance liquid chromatography with a mass detector (HPLC – MS/MS). This method was used for deoxynivalenol determination in barley and malt produced from this barley. The bachelor´s thesis was implemented in the Research Institute of Brewing and Malting, Plc. in Brno.
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Developement and optimization of the method for the extraction of ferulic acid from wheat bran
Hubačová, Klára ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
Bachelor thesis is considering usage of wheat bran for an extraction of ferulic acid. Wheat bran is a large-scale by-product of milling industry which is produced during milling of cereals (wheat) into flour. This low-cost product is usually used as a livestock feed. An initiative is raised for some other potential applications, because too large quantity produced every year can not be consumed just as a feed. There is a significant amount of phenolic acids from which ferulic acid is the most abundant one. It was found out after examination of structure of the wheat bran. This acid is connected with polysaccharides of a cell wall. The alkaline hydrolysis was used to disrupt a linkage between ferulic acid and polysaccharides. Then ethanol was added to precipitate the polysaccharides and the mixture was filtered. The filtrate contains ferulic acid which has great health benefits such as anti-inflammatory, antioxidant, anti-carcinogenic, antimicrobial effect etc. It plays an important role as an agent against UV radiation in the cosmetic products.
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Characterisation of chokeberry and saskatoon berry fruits
Burdějová, Lenka ; Omelka, Ladislav (referee) ; Vítová, Eva (advisor)
Diploma thesis deals with the characterization of chokeberry (Aronia melanocarpa) and saskatoon berry (Amelanchier alnifolia) fruits. The theoretical part focuses on the botanical classification, chemical composition, curative effects and the use of chokeberry and saskatoon berry in the food industry. Further, the attention is also devoted to a review of methods for the determination of important antioxidants, specialized on the determination of polyphenols, anthocyanins, ascorbic acid and total antioxidant activity. The experimental part of the work deals with the determination of selected parameters in different varieties of chokeberry and serviceberry, harvested in 2012 and 2013 using spectroscopic and chromatographic techniques with an emphasis on effect of solvent (50% ethanol, destilled water, DMSO). Specifically total content of polyphenols and anthocyanins, color characteristics using the CIE L*a*b* system and the ability of the sample to reduce the iron are determined using the UV-VIS-NIR spectroscopy. Further ascorbic acid concentration in individual extracts is quantified by High performance liquid chromatography coupled with a diode array detector and the total antioxidant activity is characterized by electron paramagnetic resonance involving •DPPH and ABTS•+ assays.
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Comparison of vitamin C content between less known kinds of fruit
Mařáková, Veronika ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
This thesis deals with the determination of vitamin C in different varieties of cornelian cherry (Cornus mas) and mountain ash (Sorbus aucuparia). The theoretical part describes the botanical characteristics of both plants, the extension in the CZ and in the world, methods of reproduction, the content of meaningful health substances and the importance of both plants in food-processing industry. Attention is paid to vitamin C, which is in their fruits in high quantity. Conclusion of the theoretical part discusses various methods of determination of vitamin C. The aim of the experimental part was to comparison of the vitamin C content in different varieties cornelian cherry and mountain ash. The chosen method for the determination of vitamin C by high performance liquid chromatography (HPLC) with UV detection was first tested on standards. Selected validation parameters of this method was then determined. Validated method was used to determine the content of vitamin C in nine varieties cornelian cherry and six varieties of the mountain ash. For comparison were also tested some samples of the determination of total vitamin C after reducing dehydroascorbic acid by using dithiothreitol (DTT).
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Determination of zearalenone in malting barley
Wawroszová, Simona ; Čumová,, Martina (referee) ; Běláková, Sylvie (advisor)
This bachelor thesis deals with monitoring of zearalenone content in malting barley using immunochemical method ELISA and consequently method of liquid chromatography with mass spectrometry (LC-MS/MS). Theoretical part describes the brewing raw materials and important toxinogenic filamentous fungi. Special attention was drawn to selected fusarium mycotoxins (fumonisins, trichothecenes, zearalenone). It also describes some methods for determination of mycotoxins. Experimental section describes analyze 90 samples of malting barley of different varieties using method ELISA. In 19 samples zearalenone concentration was higher than limit of quantification. The highest level of zearalenone concentration (39,2 g•kg-1) contained barley, variety Wintmalt, where corn was used as a fore-crop. The samples were subsequently analyzed by LC-MS/MS. Zearalenone concentration was higher than limit of quantification only in four samples, namely in samples of Blaník, Malz and Wintmalt varieties of barley. Furthermore, the samples of intermediate products of malting process were analyzed by LC-MS/MS. No sample showed level of zearalenone higher than limit of quantification.
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Analysis of onion and garlic samples of different geographical origin
Korček, Jakub ; Mikulíková, Renata (referee) ; Diviš, Pavel (advisor)
Presented master thesis dealt with the analysis of garlic and onion samples and tried to find correlations between chemical composition and country of origin. The parameters examined were dry content, crude protein content, concentration of phenolic compunds, carbohydrate content (fructose, glucose), alliin content and concentration of selected elements (P, Mg, Ca, Na, K, Fe, Zn). Average content of dry matter of fresh samples was 35,84 ±2,12 g/100 g and of dehydrated samples was 90,61 ±2,90 g/100 g. Concentration of phenolic compounds was measured spectrophotometrically with Folin-Ciocault reagent. Average phenolic compounds content of samples was 0,1840 ±0,1286 GAE g/100 g. Crude protein content was measured by Kjeldahl method, and calculated from total nitrogen content. Carbohydrates were measured by HPLC-ELSD after hydrolysis of fructans. Average content of fructose of garlic samples was 57,014 ±0,863 g/100 g, of onion samples was 33,718 ±1,168 g/100 g. Average content of glucose of onion samples was 22,633 ±0,405 g/100 g. Alliin content was measured by HPLC-DAD method. Average alliin content of fresh samples was 4,644 ±0,446 g/100 g and of dehydrated samples was 1,962 ±0,180 g/100 g. Elemental analysis was conducted by ICP-OES method. Average concentration of selected elements was: P 2,15 ±0,11 mg/g, Mg 0,638 ±0,03 mg/g, Ca 1,246 ±0,05 mg/g, Na 0,550 ±0,08 mg/g, K 7,49 ±0,41 mg/g, Fe 79,3 ±6,16 mg/kg, Zn 11,4 ±3,33 mg/kg. Obtained data were statistically processed on significance level 0,05. Based on the principal components analysis, it was found, that the best parameters to differentiate samples from Czechia, Poland and Ukraine from other countries were content of nitrogen, phosphorus, magnesium, sodium and calcium. It was also discovered, that genus differences between onion and garlic have greater significance than geographical differences.
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Development and validation of the analytical method for the purity assessment of Nalbumin hydrochloride
Děd, Jozef ; Maliarová,, Mária (referee) ; Mrázová,, Viera (advisor)
High Performance Liquid Chromatography is currently used for the purpose of analytical evaluation of drugs. This is mainly because it allows the separation method both, a qualitative and a quantitative, analysis of high selectivity mixture evaluation and sensitivity. The diploma thesis deals with the issue of purity evaluation of pharmaceutical substance Nalbufin hydrochloride. The aim of the experimental part of the diploma thesis deals with the development and validation of the analytical method for assessing the purity of Nalbufin hydrochloride.An HPLC method was developed on a Nova-Pak C18 column. The mobile phase consisted of two components A and B. MF A composition was as follows: 0.97 g of sodium octane sulfonate was dissolved in 900 mL of water to which were added 100 mL of acetonitrile and 2 mL of triethylamine. Created solution was treated with phosphoric acid to pH 2.5. MF B had the following composition: 0.86g of sodium octanesulfonate was dissolved in 800 mL of water to which 200 mL was added acetonitrile of 2 mL of TEA. The resulting pH was adjusted to pH 2.5 with phosphoric acid. gradient MF had the following composition: From zero minutes from 100% A to 30 min. to 0% A. The 30-60min. 0% A, 60-61 min. with a linear change to 100% A, 61-70 min. equilibrium into the original conditions to 100% A at a flow rate of 1 mL/min. In the following section we evaluated the basic validation parameters: linear dynamic range 0.3 - 4.5 g/mL, we calculated the linear regression equation for Nalbuphine in R2 (0.9999), Oxycodone R2 (0.9999) and Noroxycodone R2 (0.9998). The method gave us detection limits for Nalbuphine 0.069 g/mL. Oxycodone had a detection limit of 0.053 g/mL and Noroxycodone 0.048mg / mL. The limist of quantification in these cases were 0.209 g / mL for Nalbuphine, 0.161 g/mL for Oxycodone and 0.147 g/mL for Noroxycodone. Repeatability for the limit of quantification was also set expressed by the relative standard deviation. For Nalbuphine - RSD = 0.40%, Oxycodone - RSD = 2.39% and Noroxycodone - RSD = 1.25% (RSD 7.0%). The following validation parameter was accuracy. The resulting RSD was 0.44% (RSD 5.0%). The last evaluated parameter was robustness. For pH 2.4, the change value was resolution of 1.5% and repeatability of RSD = 0.85%. The change of resolution value for pH 2.6 was 2.8% and repeatability RSD = 1.29% (max. 5% limit). The second factor observed for the robustness was the temperature change of the column. The arithmetic average was calculated from the individual peak areas and relative standard deviation RSD = 3.45% was evaluated with the change of resolution, which had a value of 3.34%. Thus, we can state that the developed chromatographic method has been verified in the givenvalidation parameters and is suitable for determining the purity of Nalbuphine hydrochloride.
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Determination of hydroxymethylfurfural in honey
Dohnalová, Barbora ; Slavíková, Zuzana (referee) ; Diviš, Pavel (advisor)
Honey is a valuable food of a natural nature that can be subject to adulteration for higher profits. One method of detecting this adulteration may be to determine hydroxymethylfurfural, the formation of which is promoted by heating. The theoretical part of the thesis deals with the types of honey, their origin, and the possibilities of their falsification. HMF, its occurrence and use and methods for its determination are also described. The practical part is devoted to the description of the experiment such as sample preparation, measurement and evaluation. The HPLC (high performance liquid chromatography) method was used to determine HMF in honey, which can be used to determine even very low concentrations. There were five samples for the experiment, four of them directly from the beekeeper and one from the retail chain. All samples were compared for HMF content. The highest concentration of HMF was determined in a sample of commercially available honey. In domestic honeys, the HMF content increased with the age of the honey. The content of HMF in all honeys complied with Decree No. 76/2003 Coll.
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