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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Plynová chromatografie esterů mastných kyselin ve vybraných druzích potravin

Rozíková, Veronika January 2010 (has links)
No description available.
2

Studium korelací jakostních parametrů vín a destilátů

Veverka, Lukáš January 2012 (has links)
PhD dissertation thesis "Study of correlation of quality parameters of wines and wine distillates" was done at Department of Post-Harvest Technology of Horticultural Products, Faculty of Horticulture, Mendel University of Agriculture and Forestry in Brno during 2006 - 2012. Samples of wines and samples of distillates made from these wines were analysed using liquid-liquid extraction method (LLE) followed by gas chromatography analysis (GC). Potential characteristics -- chemical markers were determined: trans-linalool oxide and cislinalool oxide which are typical for Muscat Ottonel and tetradecanote, ethyl 3- methylpentanoate for Pinot Blanc. In wine distillates, ethyl 2-methylbutanoate, ethyl 3- methylpentanoate, 1,1-diethoxybutane, diethoxypentane were determined, however none of these substances were found in wines. These substances probably originate as a result of esterification process during ageing of wine distillates after distillation process. Differences in chemical composition of wine distillates made from red wine grape cultivars were analysed using main component method. Group of substances such as ethyl butanoate, hexanoate, octanoate, decanoate, dodecanoate and diethyl succinate can be considered as possible markers identifying wine distillates from red wine grape cultivars and white grape cultivars. Characteristic aroma of grape variety was recognisable in wine distillates from Muscat Ottonell and Blue Frankish varieties. Samples of wine and wine distillates were analysed using Solid-phase micro extraction (SPME-headspace) technique followed by Gas chromatography--mass spectrometry (GCMS). Negative correlation between 1-hexanol content and intensity of aroma was discovered in wine distillates. Characteristic aroma of grape variety showed significantly in distillates from Pinot Gris (RS_2) and in distillates from red wine grape cultivars, particularly Saint Laurent (SV) and Pinot Noir. Based on analysis of samples of wine distillates from red wine grape cultivars, ten major terpentic aromatic substances were determined (o-cymen, limonen, cis-b-ocimen, cislinalool oxid, linalool, isoborneol, terpinen-4-ol, a-terpineol, trans-sabinyl acetate a transkalamenen). All these substances influence aroma of grape variety. Both centred log ratio transform (clr) and main component method were applied and similarity in aroma of wine distillates was found and it was discovered that aroma of wine distillate from varieties Merlot, Pinot Noir and similar ones are influenced by terpenoids cis-linalool oxid, linalool, 94 isoborneol, terpinen-4-ol a a-terpineol. On the other hand, aroma of wine distillates from varieties Blue Portugieser and Cabernet Sauvignon are influenced by o-cymen, limonen, trans-sabinyl acetate and trans-kalamenen. Analysis of terpentic content wine distillates was carried out using Solid-phase micro extraction (SPME-headspace) technique followed by Gas chromatography--mass spectrometry (GC-MS).Major terpentic substances identified are limonen, linalool, a-ylangen, b- bourbonen, g-kadinen, trans-nerolidol, 2,3-dihydrofarnesol and (2-cis, 6-trans)-farnesol. Verifiable differences were discovered between various distillates types. Predominantly mono-terpentic substances were identified in wine distillates; in grappa there were also identified sesquiterpenic substances which are characteristic for these types of distillates.
3

Aromatický profil mladých vín

Tomanová, Barbara January 2015 (has links)
Aromatic compounds belong to the most valuable substances that give the wine a distinctive expression and are important for sensory evaluation of wine. We chose two samples of white wine - Grüner Veltliner and Sauvignon, where we have set aromatic compounds. Wines were concluded with two different closures (screw cap and classic cork) and then these wines were stored for one year in two conditions different especially by temperature - cool in the cellar and at room temperature. After a year of storage, we have set the aromatic compounds again. The most significant decrease was in the esters of higher alcohols with acetic acid (especially isoamyl acetate and hexyl acetate). These esters are typical for young wines and give them fruitiness particularly. The decrease of these substances was detected in both conditions of storage, but during storage at room temperature was more pronounced. Impact of the closure wasn`t proved. Temperature is a very important factor which influences the aromatic compounds during storage.
4

Identifikace senzoricky aktivních látek v konopí / Identification of aroma compounds from Cannabis

Jarošová, Šárka January 2017 (has links)
Hemp is a complex system of chemicals which interacts with one another. The most important chemicals in cannabis are cannabinoids and terpenoids. These compounds evince synergism that makes a number of medicinal effects, e.g. antioxidant, anti-inflammatory, antifungal and analgesic. Volatiles cause aroma of cannabis and have therapeutic effects when it is inhaled. The main of this study was to identify sensory active compounds in the varieties of cannabis by GC-MS/FID and sensory analysis by GC-MS/O. There were 7 samples of varieties to analysis: Cannatonic (CT) Conspiracy Kush (CK) Jillybean (JB) Jacks Cleaner (JC), Jack Skellington (JS) Nordle (N) and Nurse Jackie (NJ). Selection of these varieties was based on its genetic origin - the ratio of morphological types C. sativa and C. indica. Aromatic compounds were extracted by using SPME fiber. Sensory analysis was performed by one trained sniffer. The results show that the most represented volatiles in cannabis varieties (both in C. sativa and C. indica) is myrcene. This terpenoid was in the greatest amount in variety of N (33.4%), NJ (29.8%), CT (29.7%) and JB (29.7%). Then beta-caryophyllene had a large number of presence with high ratio in CK variety (21.1%), JC (20%) and NJ (14%). In the varieties with higher level of morphotype C. indica (CK, N), there were limonene and alpha-humulene represented. Results based on the sensory analysis showed, that sensory activity of limonene, linalool and alpha-humulene is higher in varieties with greater ratio of C. indica. The varieties with a higher ratio of morphotype C. sativa were rich in myrcene and terpinolene.
5

Obsah PUFA n-6 a n-3 ve vybraných živočišných tkáních

Koláčková, Martina January 2016 (has links)
The literature review summarizes characteristics of polyunsaturated fatty acids, problems of their metabolism, physiological effects and their occurrence in food. It pursues procedures and possibilities of fatty acids assessment with the help of gas chromatography. Experimental part of the thesis describes an assessment of fatty acids profile in fallow deer meat, roe deer and deer meat using the gas chromatography method operating the Fison 8000 series gas chromatograph as well as flame ionization detector. Conclusive differences in content of particular fatty acids and n-6/n-3 fatty acids ratio among single types of venison are being monitored by means of statistic processing. .
6

Plynová chromatografie mastných kyselin ve vzorcích vepřového masa

Maděrová, Petra January 2011 (has links)
No description available.
7

Jakost vína ovlivněná řízeným kvašením

Mertová, Pavla January 2011 (has links)
No description available.
8

Vliv stavebních materiálů na zatížení vnitřního ovzduší interiéru

Bohatá, Jana January 2007 (has links)
No description available.
9

Vliv skladování na změny obsahových látek konopí

Vomáčka, Vít January 2017 (has links)
This thesis deals with the effect of storage of cannabis on the level of content of its active substances. The theoretical portion focuses on a botanical characteristics sum-mary. It further describes the growing needs and options of cannabis on the fields and of medical cannabis in covered areas. Portion of the thesis deals with the use of each individual parts of the cannabis plant. The thesis contains detailed description of canna-binoids and other substances. It further describes the effect of individual external factors on the stability of cannabinoids in cannabis products. The last part of the theore-tical section deals with the ability to analyze cannabinoids. The goal of the experimental section was to discover effects of different type of storage on the level of content of cannabidiol and delta-9-tetrahydrocannabinol in cannabis samples. The setting included a gas chromatograph GC Fisons instruments with FID detector. These samples were regularly collected and ex-tracted during the period of one year. Retention periods of individual cannabinoids and calibration curves were created. The results showed a reduction of cannabinoids in higher temperatures. The results further confirmed storage of vacuumed materials at -20 °C temperature as the most appropriate type of storage for female inflorescence of can-nabis.
10

Vliv přídavku oleje do krmiva modelového organismu na zastoupení mastných kyselin ve vybraných tkáních

Kaňoková, Linda January 2019 (has links)
The Master's thesis deals with the effect of feed enrichment with various types of oils on the deposition of fatty acids in selected tissues. Forty male Wistar Albino rats were divided into four groups and fed for 10 weeks daily ad libitum with a basic feed mixture enriched with 8 % palm, 8 % safflower, 8 % fish oil or 8 % microalgae Schizochytrium sp. oil. Rats had also free access to the drinking water. Fat from the tissue samples (liver, muscle, visceral fat) was extracted, converted to methyl esters and analyzed with usage of gas chromatography. The results of the experiment show that the addition of various types of oils to the feed of model organism can influence the deposition of fatty acids in its tissues. The addition of fish oil and microalgae Schizochytrium sp. oil caused statistically significant decrease (p < 0,05) in the ratio of PUFA n-6/n-3 in all observed tissues to a value of 1 or less compared to the addition of palm and safflower oil. Low ratio of n-6/n-3 polyunsaturated fatty acids is considered to be more desirable in reducing the risk of cardiovascular diseases.

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