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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.
31

Use of plant-derived essential oil compounds and naturally-occurring apple flavor compounds to control foodborne pathogens in apple juice

Abdulmalik, Takiyah 25 April 2012 (has links)
Recent demands for minimally-processed foods, has led to the exploration of plant-derived essential oil (EO) compounds as an alternative means of preservation. While some of these compounds are effective against foodborne pathogens, their strong aroma and "spicy" flavor are not compatible with the flavor of juice. The purpose of this research was to evaluate the antimicrobial activity of three EO compounds (thymol, eugenol, and trans-cinnamaldehyde) alone and in combination with three naturally-occurring apple aroma compounds (hexanal, trans-2-hexenal and 1-hexanol) in order to identify combinations that lower the concentrations needed to destroy foodborne pathogens in apple juice. The standard agar dilution method (SAD) and the Spiral Gradient Endpoint method (SGE) were compared for their abilities to determine minimum inhibitory concentrations (MIC) of the EO compounds. Both methods produced similar patterns of inhibition; however, the MICs produced by the SGE system were significantly higher than those produced by the SAD method of analysis (P<0.05). Since the results produced by the SAD method were more comparable with those published in literature, this method was selected for further testing. In general, the EO compounds were significantly more effective against the test pathogens (Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aurues) than were the apple aroma compounds (P<0.05). Cinnamaldehye exhibited the highest degree of activity, followed by thymol and eugenol. Eugenol was the only compound that acted synergistically with the apple aroma compounds. The most effective compounds (cinnamaldehyde, eugenol and trans-2-hexenal) were then used to inactivate L. monocytogens and S. Typhimurium in preservative-free apple juice. In most cases, treatment with 0.05% of each compound resulted in a 5 log CFU/ml reduction in bacterial numbers following one day of storage at 4°C or 25°C. Likewise, treatment with antimicrobial combinations (containing 0.025% of trans-2-hexenal in combination with 0.025% trans-cinnamaldehyde or eugenol) also resulted in a 5 log CFU/ml reduction in bacterial numbers, following one day of storage at 4°C or 25°C. Since these combinations contained half the effective concentration of the essential oil compounds, they may be used to preserve the microbial quality of apple juice, while reducing the likelihood of off flavors in the final juice product. / Ph. D.
32

Effect of Foliar Nitrogen and Sulfur Applications on Aroma Profile of Vitis vinifera L. cv. Petit Manseng using Modified Quantitative Descriptive Analysis, SPME GC-MS and Electronic Nose Technology

Kelly, Molly Kathleen 12 June 2013 (has links)
Petit Manseng grapes harvested in 2011 and 2012 were fertilized with soil nitrogen at 0, and 30 kgN/ha, foliar nitrogen at 15kg/ha and foliar nitrogen plus sulfur at 15kg/ha and 5kg respectively. Point quadrat analysis demonstrated foliar nitrogen alone and nitrogen plus sulfur treatments increased percent gaps and lower leaf layer numbers. Berry juice samples differed in ammonia, arginine and yeast assimilable nitrogen concentration. Total glycosides were 25 percent higher in the foliar nitrogen treatment versus the control treatment. Electronic nose measurements on field clusters and laboratory berry analyses was different among treatments in volatile content. Harvest samples underwent acid or enzyme hydrolysis of precursor fractions. Solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC/MS) analysis identified 27 free aroma and flavor compounds and 52 bound compounds. Lactones and carboxylic acids were the major components of the free fractions while bound fractions had increased concentrations of alcohols, esters and terpenes compared to the free fraction. With nitrogen fertilization, acid and enzyme hydrolysis had reduced concentrations of some higher alcohols and carboxylic acids. Acid hydrolysis released more terpenes with nitrogen treatments versus enzymatic hydrolysis. Ester content was increased in both acid and enzyme hydrolysis fractions in vines receiving nitrogen treatments. For descriptive analysis, eight trained panelists described aroma, flavor, texture/mouthfeel and aftertaste attributes. Analysis of Variance (ANOVA) demonstrated that wines were a significant source of variation with 23 of the 24 attributes used. Wine principal component analysis (PCA) of aroma attributes explained 23.5% of the variation from PC1, while flavor-by-mouth and texture/mouthfeel attributes explained 26.3% of the variation due to PC1. The aim of this study was to develop descriptive terms for Petit Manseng and determine the influence of fruit nitrogen levels on the aroma and flavor profile of this cultivar. / Ph. D.
33

Propriétés interfaciales et émulsifiantes de gomme d'Acacia senegal, Acacia seyal et de leurs fractions / Interfacial and emulsifying properties of Acacia senegal and Acacia seyal gum and their fractions

Aphibanthammakit, Chutima 29 October 2018 (has links)
Les gommes d’Acacia (AG, E414EC) sont largement utilisées par ses propriétés stabilisantes, émulsifiantes et filmogènes. Le but de ce projet de thèse consiste à caractériser les propriétés interfaciales et émulsifiantes des gommes d’Acacia. Les études des propriétés interfaciales liquide-liquide ont confirmé que l’A. senegal permettait une plus grande diminution de la tension interfaciale et une formation plus rapide de films à l’interface. Ceci est en accord avec sa teneur plus élevée en AGP de masse molaire élevée riche en protéine, la meilleure accessibilité de la partie protéique et la plus grande flexibilité moléculaire par rapport à A. seyal. De même, ces avantages biochimiques et structuraux de l’A. senegal se sont avérés être impliqué dans les propriétés émulsifiantes des gommes. Les résultats d'une approche innovante visant à contrôler la teneur en AGP de masse molaire élevée riche en protéines dans le milieu et la concentration totale de gomme par le mélange de deux fractions bien caractérisées isolées chez A. senegal ont confirmé la synergie fonctionnelle entre la quantité des AGP de masse molaire élevée riche en protéines et la concentration totale en gomme. De plus, en présence de quantités élevées d'AGP de masse molaire élevée riches en protéines, les émulsions étaient stables contre la floculation/coalescence en raison de la forte teneur en protéines permettant une répulsion électrostatique entre les gouttelettes et la viscosité apparente élevée du milieu. Celles-ci étaient en accord lorsque les propriétés émulsifiantes de A. senegal et A. seyal ont été comparées. En effet, A. senegal contient une plus grande quantité d'AGP de masse molaire élevée riches en protéines et d'acides uroniques, et sa dispersion présente une viscosité apparente supérieure à celle d'A. seyal. En outre, lorsque les gommes d'Acacia étaient utilisées sous forme de films séchés, la grande teneur en AGP riches en protéines de masse molaire élevée et la bonne accessibilité des fragments protéiques d'A. senegal permettaient aux films d’avoir une surface homogène lisse avec des propriétés hydrophobes caractéristiques. En revanche, les films de A. seyal étaient irréguliers et constitués d'une organisation répétitive comme de nombreuses grosses particules uniformément réparties sur la surface par rapport au faible degré de ramification, une teneur élevée en arabinose favorisant les liaisons hydrogènes intra et inter moléculaires et une forte capacité d'hydratation chaînes polysaccharidiques de A. seyal. Selon les résultats, cette thèse apporte de nouvelles connaissances sur la relation entre la composition biochimique, les propriétés structurales et physico-chimiques, pour la première fois, dans les deux aspects de la gomme, à savoir sous forme de dispersion liquide et de films séchés.Mots clés : gomme d’Acacia, propriétés interfaciales et émulsifiantes, arabinogalactane-protéines, arômes / Acacia gums (AG, E414 EC) are widely used for its stabilizing, emulsifying and film-forming properties. The aim of this project is to characterize the interfacial and emulsifying properties of Acacia gums. The main results from liquid-liquid interfacial properties study confirmed that A. senegal showed a faster decrease of interfacial tension and a more rapid interfacial film formation. These were in agreement to its greater content of high molar mass-protein AGPs content, the more accessibility of proteinaceous moieties, and the higher molecular flexibility compared to A. seyal. In the same vein, these biochemical and structural advantages of A. senegal were found to be involved in the emulsifying properties of gums. The results from an innovative approach aiming to control high molar mass protein-rich AGPs content in bulk and the total concentration of gum by mixing two well characterised fractions isolated from A. senegal confirmed the functional synergism between the amount of high molar mass protein-rich AGPs and the total gum concentration. Moreover, in the presence of high molar mass protein-rich AGPs in high amount, the emulsion became stable to flocculation/coalescence due to the great protein content allowing electrostatic repulsion between droplets and the high bulk apparent viscosity. These were in agreement when the emulsifying properties of A. senegal and A. seyal were compared. Indeed, A. senegal containing a greater amount of high molar mass protein rich AGPs and uronic acids and its dispersion having a higher apparent viscosity than A. seyal allowing the former to form emulsion with a more stability. Besides, when Acacia gums were used in the form of dried film, the great content of high molar mass protein-rich AGPs and the good accessibility of proteinaceous moieties of A. senegal allowed the smooth homogeneous surface with a hydrophobic characteristic properties of A. senegal dried films. In contrast, A. seyal films was irregular and composed of a repetitive organization as numerous large particle uniformly distributed on surface in the relation to the low degree of branching, high arabinose content favoring intra and inter molecular hydrogen bonding and high hydration ability causing aggregation of polysaccharide chains of A. seyal. According to the results, this thesis brings new knowledge of the relationship between biochemical composition, structural and physicochemical properties, for the first time, across both aspects of gum, i.e. in the form of liquid dispersion and dried films.Keywords: Acacia gums, interfacial and emulsifying properties, arabinogalactan proteins, aroma compounds
34

Aroma-producing yeasts associated with cocoa beans fermentation: starter culture selection for flavor modulation of chocolate

Alvarez, Jonatan Peregrino 22 March 2017 (has links)
Chocolate is one of the most important products for the food industry, being of economic interest all over the world. The cocoa quality depends directly on the post-harvest processing, being the cocoa-pulp fermentation a crucial step for chocolate quality development. The aim of this work was to study the diversity of aroma-producing yeasts associated with cocoa beans fermentation and to select suitable yeast starter culture to cocoa flavor modulation. A total of 39 cocoa-derived yeast isolates were screened for their capacity to produce volatile aroma compounds in a cocoa pulp simulation medium. The seven highest aroma-producing yeasts were identified by ITS-rRNA gene sequencing as belonging to Pichia kudriavzevii, in spite of exhibiting different metabolic profiles. A computer-assisted analysis of rep-PCR genomic fingerprints of Pichia kudriavzevii strains clearly differentiated the upper aroma-forming yeast strains (G1 group; P. kudriavzevii LPB06 and P. kudriavzevii LPB07) from the other strains (G2 group). This demonstrates the potential of rep-PCR technique as a promising genotypic tool for rapid and reliable speciation of aromatic yeast strains. In the second stage of this study, two strains with superior aroma production, namely P. kudriavzevii LPB06 and P. kudriavzevii LPB07, were used in cocoa beans fermentation at laboratory scale. They were able to establish an accelerated fermentation process with efficient yeast growth, sugars consumption and ethanol formation compared to the spontaneous process. The resulting cocoa beans were analyzed by diverse chemical analysis methods, including SPME-GC/MS, FTIR spectroscopy and metal and colorimetric analysis. All together, the results indicated that inoculated fermentations generated cocoa beans with better color development and richer aroma composition, suggesting that cocoa-associated yeast diversity at strain level can be exploited for flavor modulation of cocoa beans. / Atualmente, o chocolate é um dos produtos mais importantes para a indústria de alimentos, sendo de interesse econômico em todo o mundo. A qualidade do cacau depende diretamente do processamento pós-colheita, sendo a fermentação da polpa um passo crucial para o desenvolvimento da qualidade do chocolate. O objetivo deste trabalho foi estudar a diversidade de leveduras aromáticas associadas à fermentação de cacau e selecionar uma cultura iniciadora com potencial para modular o flavor de chocolate. Um total de 39 leveduras foram isoladas e caracterizadas quanto à formação de compostos aromáticos. As sete melhores produtoras foram identificadas através do sequenciamento do gene ITS-rRNA como Pichia kudriavzevii, apesar de apresentarem diferentes perfis metabólicos. Análise de impressões digitais (fingerprints) dos isolados pela técnica de rep-PCR claramente distinguiu as cepas com maior produção de compostos aromáticos, demonstrando o potencial desta técnica como uma ferramenta para rápida e confiável seleção de leveduras. Na segunda etapa deste estudo, duas cepas com superior formação de aroma (P. kudriavzevii LPB06 e P. kudriavzevii LPB07) foram testadas como culturas iniciadoras para fermentações de cacau em escala laboratorial. Estas duas cepas foram capazes de estabelecer um acelerado processo fermentativo, com eficiente consumo de açúcares e formação de etanol, em comparação ao método natural. As amêndoas de cacau resultantes destes processos foram analisadas por diferentes métodos químicos, incluindo SPME-GC/MS, espectroscopia FTIR e análises de metal e calorimetria. Os resultados indicaram que as fermentações inoculadas desenvolveram amêndoas de cacau com melhor cor e composição de aroma, sugerindo que a diversidade de levedura em fermentações de cacau pode ser explorada para a modulação do flavor de chocolate.
35

gamma-Lactones in wine: Synthesis, quantification and sensory studies

Brown, Rachel Christine, rcbrown@adam.com.au January 2007 (has links)
gamma-Lactones are found in a wide variety of food and beverage products, in particular grapes and wine. This thesis details the work completed on some gamma-lactones in wine: their synthetic preparation, development of quantification methodologies and sensory studies. Chapter 1 outlines the history of the Australian wine industry from the arrival of the first vines on the First Fleet in 1788 with Captain Arthur Philip. This chapter provides: an overview of Australia’s position in the world of grape and wine production; an analysis of the export arm of the industry; and a look at the different wine producing regions around the country. The latter part of the chapter focuses on the different volatile compounds found in wine. Part A: Chapter 2 provides an overview on the history of barrel manufacture and the use of oak wood in cooperage, with an emphasis on oak’s well known ability to impart desirable characteristics to wine through the extraction of volatile aroma compounds. This chapter provides a summary of these odorants with a particular emphasis on the oak lactones. Previous sensory studies and synthetic work are discussed. Of great importance to this work are the recent advancements in 1,2-dioxine chemistry, highlighted in this chapter. Chapter 3 details the synthetic work completed for the preparation of all four possible oak lactone stereoisomers. A suitably substituted racemic 1,2-dioxine featured as the common intermediate and enabled preparation of the gamma-lactone moiety upon reaction with a chiral malonate diester and separation of the diastereomers by column chromatography. A key step involved the decarboxylation of the ester cleaved gamma-lactone diastereomers, which could be directed to give either the cis- or trans-products. Standard chemical transformations were then utilised to produce the desired stereoisomers of oak lactone. Chapter 4 describes the results from the sensory studies that were completed on the synthetic oak lactone samples. Odour detection thresholds were measured in both a white and a red wine. The thresholds in the former medium were calculated to be 24 ug/L, 172 ug/L, 132 ug/L and 305 ug/L, while in the latter medium the thresholds were calculated to be 57 ug/L, 380 ug/L, 175 ug/L and 285 ug/L, for (4S,5S)-cis-, (4S,5R)-trans-, (4R,5R)-cis- and (4R,5S)-trans-oak lactone, respectively. Difference testings were completed on the pairs of enantiomers and also on mixtures of the nature-identical isomers: between the cis-enantiomers a significant difference was found at the 99% confidence level, while between the trans-enantiomers and also the mixtures of cis- and trans-isomers little difference was observed. Chapter 5 contains the experimental procedures for Part A. Part B: Chapter 6 discusses the sensory properties of some gamma- and delta-lactones, with the focus on a series of five-alkyl substituted gamma-lactones: gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone. Topics covered in this chapter include chirality, biosynthetic pathways and quantification results in wine from previous studies for these gamma-lactones. Chapter 7 concerns the method development for the quantification of gamma-lactones in wine using a stable isotope dilution assay (SIDA). Deuterated analogues were prepared from commercially available racemic gamma-lactones for use as internal standards. Initially a head space solid-phase microextraction (HS SPME) method was developed using d5-standards; however, analysis of bottled wine samples revealed the presence of co-eluting compounds that contained several of the selected ions. Thus an alternative method was developed using d7-standards, with a specific focus on sample clean-up, via solid-phase extraction (SPE). Using this procedure, 44 white and 120 red wines were analysed for their gamma-lactone content. The lactones were found to be significantly more common in the red wines, with gamma-nonalactone the most abundant lactone in this series. Chapter 8 deals with the extension of the SIDA method, as developed in Chapter 7, for use with a chiral gas chromatography column. Optically pure standards were prepared, from either L- or D-glutamic acid, and used to determine the order of elution of the enantiomers. A method was developed for the quantification of the individual enantiomers of gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone. The enantiomeric distribution of gamma-nonalactone was investigated in 34 red wines; the (R)-stereoisomer was found to be dominant with an average of 59%, although there were wines analysed that did contain the (S)-stereoisomer in greater amounts. Chapter 9 describes the results from the sensory studies that were completed on the individual enantiomers of the gamma-lactones. Odour detection thresholds were measured in a red wine. The thresholds were calculated to be 238 ug/L, 285 ug/L, 34 ug/L and 8 ug/L for the (R)-enantiomers, while the thresholds were calculated to be 135 ug/L, 91 ug/L, 47 ug/L and 39 ug/L for the (S)-enantiomers, of gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone, respectively. Chapter 10 contains the experimental procedures for Part B. Chapter 11 contains the appendices, followed by the references in Chapter 12.
36

Výroba a charakterizace sýrových analogů s přídavkem rostlinného oleje / Production and characterization of cheese analogues with the addition of vegetable oil

Babištová, Lucie January 2021 (has links)
This thesis deals with the production and characterization of cheese analogues, ie products in which some of the dairy components are mutually or completely replaced by a non-dairy component. Model samples of fresh cheese and analogues of fresh cheese (standard) with the addition of linseed and rapeseed oil were produced by a standard technological procedure in MENDELU Brno. The content of bound and free fatty acids, volatile (aroma) substances and sensory quality was monitored in the samples. The main focus was to evaluate the effect of added vegetable oil on the monitored parameters. The fats from the sample were extracted with a mixture of diethyl ether and petroleum ether. Fatty acids were converted to methyl esters by boron trifluoride-catalyzed acid esterification and subsequently identified by GC-FID. The analysis found a higher content of fatty acids in cheese analogues in comparison with the control sample, also the content of unsaturated fatty acids increased. The HS-SPME-GC-MS method was used for the identification and semi-quantification of volatile substances (aromatic substances). 56 volatile compounds were identified in the samples; The percentage of individual chemical groups differed significantly, the highest content was found in the control sample. Sensory evaluation was performed using a scale and a serial test. In all of monitored indicators (apparence, color, consistency, smell and taste) the control sample was evaluated as best. As for the analogues the taste and smell of used oils were detected, which was unpleasant for the evaluators. The obtained results show that the addition of vegetable oils increases the nutritional value of cheeses (higher content of unsaturated fatty acids), but reduces their sensory quality and overall consumer acceptability.
37

Vliv použitého oleje na složení a senzorickou kvalitu sýrových analogů / Influence of oil used on composition and sensory quality of cheese analogues

Buldra, Martin January 2020 (has links)
This paper deals with the manufacture and characterisation of cheese analogues, which are products, where the milk components are totally or partially replaced by non-milk components. Model samples, edam type cheese and the analogue containing hazelnut oil, were manufactured using the standard way at Brno Mendelu. The main parameters chosen to describe the quality of samples were free and bound fatty acids, volatile compounds and sensory quality. The main aim was to judge the influence of added hazelnut oil on mentioned parameters. For the identification and semiquantification of volatile compounds HS-SPME-GC-MS method was used. Fat extraction from sample was made with a mixture of two solvents (diethylether, petrolether), fatty acids were identified and quantified by GC-FID, with their former acid transesterification using methanolic solution of BF3 as a catalyst. For sensory analysis of the appearance, colour, texture, aroma, taste and overall acceptance of the sample descriptive scales and comparison with standard were used, the structure was observed by electron microscopy. The results show that addition of hazelnut oil affects the sensory properties, ripening process (higher amount of volatile compounds, faster lipolysis), nutrition value (higher amount of unsaturated fatty acids), and the stability of the product.
38

Stanovení aromaticky aktivních látek v odrůdách jablek / Assessment of aroma active compounds in cultivars of apples

Mahdalová, Martina January 2014 (has links)
The aim of this master‘s thesis was to determine the aroma active compounds and monitor the sensory quality of apples. The theoretical part deals with the description, composition and properties of apples, information about the aroma compounds, their determination and possibilities for sensory evaluation of apples is also given. The gas chromatography method combined with the solid-phase microextraction, utilized for the specification of aroma compounds, is described. In the experimental part, the SPME-GC-FID method was applied on selected cultivars of apples specially cultivated against apple scab (Venturia inaequalis), i.e. 24 genotypes and Golden Delicious as the control variety. In total 60 various aroma compounds were identified, 22 alcohols, 12 aldehydes, 11 ketones, 10 esters and 5 organic acids. The number and concentration of compounds identified differed according to the cultivars. Sensory analysis was performed using category ordinal scales and the profile test.
39

A FUNDAMENTAL AND APPLIED APPROACH TO SELECTED ION FLOW TUBE-MASS SPECTROMETRIC STUDY OF VOLATILE ORGANIC COMPOUNDS IN SWISS-TYPE CHEESES

Castada, Hardy Zingalaoa 29 December 2014 (has links)
No description available.
40

Evaluating the effect of pot still design on the resultant distillate

Bougas, Nina Valleska 03 1900 (has links)
Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The total sale of brandy for 2007 in South Africa was R 7 300 000 000 and local statistics indicate that brandy is by far the most purchased spirit beverage. Sales of brandy even outweigh the total sales for whisky and the forecast for the estimated sales of brandy in the next five years is said to increase by 25%. It is therefore crucial to investigate those factors that influence the production of brandy as better understanding and control of these processes leads to the production of a brandy that is consistent and of premium quality. Many factors influence the final outcome of distillates. Of these factors, the distillation technique, the apparatus used for the purpose of distillation together with the low wine is of utmost importance as they influence the sensory profile and the chemical composition of the distillate. The effect of different variations of pot still designs on the chemical composition and the sensory profile of the resultant distillate was investigated. Five different Pot still variations were used and varied with regards to the design of their pot still head and swans neck apparatus. Two low wines were used for the purpose of distillations and were both from 2007 vintage. GCFID was used to identify the volatile compounds found in the distillates and together with Quantitative Descriptive Analysis (QDA) a profile of the distillates was produced which was used to differentiate between the different pot still variations and their effect on the final product. The data generated from the QDA sessions was subjected to Principal Component Analysis (PCA) and together with the chemical analysis a correlation between certain compounds and sensory attributes were found in the distillates. Distillate samples were also subjected to a sensory style classification system and were classified accordingly. The chemical composition of the two low wines prior to distillations differed significantly from each other with low wine one containing a larger amount of total esters and carbonyl compounds whilst low wine two contained a larger amount of total higher alcohols and acids. The distillates of low wine one also contained over all larger amounts of total esters and in the case of the distillates of low wine two, they contained larger amounts of higher alcohols and acids than low wine one. Variation one was based on the Alambic Charentais method of pot still design and it was found that only variation one influenced the chemical composition and the sensory profile of the distillates. This variation produced a distillate with a lower amount of total esters and more specifically ethyl acetate as well containing a lower intensity of the fruit and sweet associated caramel aromas and flavours. The esters, ethyl acetate and the ethyl esters of the long chained fatty acids were found to correlate with the sensory attributes known as fruit associated aroma, soapy aroma, and spicy aroma and therefore indicated that these compounds are responsible for these attributes. There were no correlations found between the chemical compounds, sensory attributes and sensory style classifications in the distillates of both low wine one and two. It was shown that the addition of certain esters, carbonyl compounds, higher alcohols and acids in specific ratios could alter the sensory classification of the distillates. Therefore the chemical composition and the sensory characteristics of distillates are largely dependent on the chemical composition of the low wine prior to distillation rather than the pot still design. Therefore, with further research it could be possible to predict the outcome of the chemical composition of the distillates by analyzing the chemical compounds found in the low wine prior to distillation. / AFRIKAANSE OPSOMMING: Die totale verkope aan brandewyn vir 2007 in Suid Afrika beloop R7 300 000 000 en statistiek wys dat brandewyn by verre die mees gesogte spiritus drank is. Verkope van brandewyn is selfs meer as die verkope van whisky en die voorspelling is dat die verkope van brandewyn met 25% gaan vermeerder in die volgende vyf jaar. Dit is dus belangrik om die faktore te ondersoek wat die produksie van brandewyn beïnvloed om sodoende die verstokingsproses te verstaan en te kontroleer om ‘n konsekwente kwaliteitsproduk op die mark te plaas. Baie faktore beïnvloed die finale produk. Faktore soos die distillasie tegnieke, die apperate wat gebruik word vir distillasie tesame met die rabatspiritus is van die uiterste belang aangesien dit die sensoriese profiel en die chemiese samestelling van die distillaat beïnvloed. Die effek van die verskillende variasies van potketelhelms op die chemiese samestelling van die distillate word ondersoek. Vyf verskillende helms met variasies in die swaannek ontwerp was gebruik. Twee verskillende rabatspiritus, van die 2007 oesjaar, was gebruik vir distillasie. GC-FID was gebruik om die vlugtige komponente van die distillate mee vas te stel. Kwantitatiewe Beskrywende Analise (QDA) is gebruik om ‘n profiel van die distillate op te stel wat weer gebruik is om te differensieer tussen die verskillende potketelhelm variasies en hulle effek op die finale produk. Die data wat deur die QDA sessies gegenereer was, is in die Vernaamste Komponent Analise (PCA) ingevoer en tesame met die chemiese analise is ‘n korrelasie tussen sekere komponente en die sensoriese analise van die distillate gevind. Distillaat monsters was ook aan sensoriese styl van klassifikasie onderwerp en is as volg daarvan geklassifiseer. Die chemiese samestelling van die twee rabatspiritus voor finale distillasie het betekenisvol van mekaar verskil ten opsigte daarvan dat die eerste rabatspiritus het hoë konsentrasies esters en karboniel verbindings gehad terwyl die tweede rabatspiritus meer hoë konsentrasies van sure en hoër alkohole gehad het. Die distillaat van die eerste rabatspiritus het ook hoë konsentrasies esters en karboniel verbindings gehad terwyl die distillaat van die tweede rabatspiritus weer hoë konsentrasies van sure en hoër alkohole gehad het. Variasie een is gebaseer op die Alambic Charentais van potketel ontwerp en daar is ook gevind dat hierdie variasie die enigste een was wat die chemiese samestelling en die sensoriese profiel van die distillate beïnvloed het. Hierdie variasie het ‘n distillaat geproduseer wat lae konsentrasies van totale esters, veral etielasetaat, sowel as laer intensiteit van vrugtige en soet geassosieerde karamel aromas en geure. Die esters, etielasetaat en etiel esters van die lang ketting vetsure, is gevind dat dit goed korreleer met die sensoriese eienskappe wat geassosieer word met vrugtige aromas, spesery-agtige aromas en seperige aromas. Daar is geen korrelasie gevind tussen die chemiese verbindings, sensoriese eienskappe en sensoriese styl van klassifikasie van distillate een en twee nie. Dit was ook bewys dat byvoeging van esters, karboniel verbindings, sure en hoër alkohole, in spesifieke verhoudings, die sensoriese eienskappe kan verander. Dus is die chemiese samestelling en sensoriese eienskappe van die distillate grootliks afhanklik van die chemiese samestelling van die rabatspiritus, voor die tweede distillasie, as wat dit afhanklik is van die potketelhelm ontwerp. Gevolglik, met verdere v navorsing, is dit moontlik om die uitkoms van die chemiese samestelling van die distillaat te voorspel deur die analise van die chemiese verbindings van die rabatspiritus te ontleed.

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