This work deals with the problem of flavour of Edam cheeses, i.e. natural hard cheese with low heat curd. The samples came from dairy MILTRA B s. r. o. Městečko Trnávka. A number of aroma active substances contribute to flavour of cheese. From the chemical point of view they are volatile compounds, including alcohols, aldehydes, ketones, fatty acids, esters, lactones, terpenes etc. Their content increases during ripening by influence of proteolytic and lipolytic changes and creates aroma, which is characteristic for type of cheese. The development of these components was monitored in chosen Edam cheese (30 % fat in dry matter) by headspace-SPME/GC method. The fiber CARTM/PDMS 85 µm was used for extraction of aroma compounds. The samples were taken from cheesemilk up to technologically ripe cheese. In total 30 aromatic compounds were identified, their content increased during ripening. The first increase was observed after pressing and then especially in second part of ripening. For comparison Edam cheese samples were also sensorially evaluated during ripening. The ordinal scale and profile tests were used for evaluation of organoleptic properties (appearance, texture, taste, aroma). The sensory quality was improved during ripening, but significant changes were not observed with regard to fine taste and smell of Edam cheese given by globally low content of aroma active compounds.

This master thesis deals with the assessment of selected fragrant substances in cosmetic products. At the beginning the occurrence, methods of acquiring and application of these substances is described. They are essential components primarily in cosmetic products, however they can cause an allergic reaction in sensitive individuals. The theoretical part of this thesis also describes the cause and the progress of these undesirable effects. There are several hundreds, up to thousands fragrant substances used in the perfume industry, from which 26 was designated by the European regulations as potential allergenic fragrant substances and their content is regulated. Legislative standards as well as the overview of the methods used to determine these fragrances are given here. The experimental part is focused on the development and validation of the separation methods for determining of the selected and potentially allergenic fragrant substances. The method used was a solid phase microextraction using Carboxen/Polydimethylsiloxane fiber combined with a gas chromatography coupled to a flame ionization detector (SPME-GC-FID). Amylcinnamyl alcohol, benzyl alcohol, cinnamyl alcohol, coumarin, lyral, ?-isomethyl ionone were among the determined allergenic substance. Consequently, this method was also applied on 10 selected cosmetic products specimens, in which the linalool and geraniol were identified as the most common allergenic substances.

This diploma thesis is focused on aromatic substances occurring in food. The theoretical part describes their characteristics, the use of fragrances of plant origin for flavoring of food and points to their possible negative effects on the human organism. Twenty six potentially allergenic fragrances are thus identified in European legislation and an overview of their physical properties, occurrence and use is also processed in this work.The aim of the experimental part was to develop and validate a method for assessment of fragrances using headspace solid phase microextraction combined with gas chromatography (HS-SPME-GC-FID). The following parameters have been validated : repeatability, linearity, limits of detection (LOD) and limits of quantification (LOQ). The HS-SPME-GC-FID method was finally applied to selected samples of foods commonly available on the market.

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.

Das Aroma von Backwaren wird wesentlich durch die verwendeten Zutaten und den Herstellungsprozess beeinflusst. So können Weizenbrote sowohl mit als auch ohne Zusatz von Vorteigen hergestellt werden, die das Brotaroma in der Regel maßgeblich verbessern. Ein Vorteig besteht aus Mehl, Wasser und der Bäckerhefe Saccharomyces cerevisiae und wird für bis zu 24 h fermentiert. Die während der Fermentation entstehenden Aromen werden durch die metabolische Aktivität von S. cerevisiae und die im Mehl vorhandenen Substrate bestimmt. In dieser Arbeit wurde daher das metabolische Potenzial von alternativen Hefen bezüglich ihrer Fähigkeit zur Aromabildung am Beispiel der Fermentation von Weizenteigen untersucht. Darüber hinaus wurde das Angebot an Aromavorstufen durch den Zusatz unterschiedlicher Nebenströme der Lebensmittelindustrie (Apfel-, Karotten- und Traubentrester oder Biertreber) erhöht. Erwartungsgemäß wirkten sich diese Zusätze unterschiedlich auf das Wachstum bestimmter Hefespezies und der davon eingesetzten Hefestämme aus. Während einige Nebenströme das Wachstum bestimmter Hefen förderte, blieben andere davon unbeeinflusst. Insbesondere die Kombination von Apfel- oder Karottentrester mit den Hefen Cyberlindera jadinii, Kluyveromyces marxianus, Torulaspora delbrueckii oder Wickerhamomyces anomalus wirkte sich positiv auf die Hefeflora und die Aromabildung aus. Weiterhin förderte vor allem der Zusatz von Karottentrester das Wachstum der ebenfalls im Teig vorhandenen Milchsäurebakterien, was allerdings keinen wesentlichen Einfluss auf das Aroma der Teige hatte. Somit ist neben den beschriebenen Inhaltsstoffen vor allem die Hefeflora ein wichtiger Faktor der Aromabildung in Teigen. Bezüglich der verschiedenen Hefestämme zeigten Propagationsstudien, dass K. marxianus DIL 82 besonders kompetitiv ist und auch nach vier Tagen Fermentation noch im Teig persistiert. In entsprechenden Teigen mit Apfeltrester wurde durch K. marxianus eine besonders fruchtige Note zugeschrieben. Die Bestimmung der in dem Teig gebildeten Aromakomponenten zeigte, dass unter anderem die Konzentration an Esterverbindungen und höheren Alkoholen durch die Fermentation mit K. marxianus DIL 82 gesteigert wurde. Backversuche zeigten, dass nicht alle der in der Fermentation gebildeten Aromen auch ins Brot gelangten, sodass das Aroma der Brotkrume stärker von dem verwendeten Nebenstrom als von dem für die Fermentation verwendeten Hefestamm bestimmt wurde. Um die Aromastudien zu komplementieren wurden mit Hilfe gentechnischer Methoden die für die Esterbildung wichtigen Gene ATF1 und EEB1 aus der Weinhefe Hanseniaspora uvarum in Kluyveromyces lactis und K. marxianus überexprimiert. Erste sensorische Analysen nach Anzucht dieser Stämme in synthetischem Medium ergaben ein eindeutig fruchtigeres Aroma gegenüber den mit Leervektor transformierten Kontrollstämmen. Die gaschromatographische Analyse zeigte allerdings nur bei Überexpression von HuEeb1 eine erhöhte Konzentration des wichtigen Aromastoffs Essigsäure-2-phenylethylester. Diese Vorversuche lassen vermuten, dass auch die Qualität von Backwaren durch gezielte genetische Veränderungen der bei ihrer Fermentation eingesetzten Hefestämme verbessert werden könnte.

In this master’s thesis, the effect of smell as a tool of sensory marketing on consumer decision making is examined. The aim of the thesis is to describe the functioning of smell in a consumer decision making context and based on gathered data suggest possible recommendations applicable for selected culinary establishments that would serve to meet the needs of consumers as well as operators of these establishments. The case is demonstrated on an empirical study carried out in the Slovak National Theatre, whereby visitors were exposed to purposefully released smells over the period of two weeks. Consumer behaviour and revenues attributable to three selected items were observed over the studied timeframe. The collected data was subsequently compared to that of a counterfactual period in which no smells were being released. A statistically significant difference was observed in the sales of all three items examined, whereby the revenues stemming from coffee and strudel saw an increase, while the revenue from savoury pastry saw a decline. At the same time, it is necessary to identify potential factors that may have skewed the obtained data. Visitors have in their consumption process felt restricted primarily by a time constraint, which is necessary to take into account for long-term application of smell as a tool of sensory marketing, as well as for future research purposes.

This diploma thesis is focused on the problematic of assessment of 26 most important allergenic aroma compounds in foods, flavoured herbal teas were chosen as the model samples. Aroma is the one of the main characteristics of tea, which is closely linked to taste and odour. The theoretical part of this work is focused on the characteristics of tea, tea types, producing technology, classification according to the fermentation and also their undeniable impact on the human organism. In the experimental part, the allergenic aroma compounds in 10 chosen samples of flavoured tea were identified and quantified using the solid phase microextraction (SPME-GC-FID) in conjunction with gas chromatography. The work also includes sensory evaluation of taste and smell of tea samples by qualified assessors.

京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第13034号 / 論農博第2835号 / 新制||農||1044(附属図書館) / 学位論文||H28||N5007(農学部図書室) / 32992 / 京都大学大学院農学研究科農学専攻 / (主査)教授 坪山 直生, 教授 黒木 裕士, 教授 妻木 範行 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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Hop (Humulus lupulus L.) is an indispensable raw material in beer brewing because it can provide unique aroma and bitterness to beer products. With growing consumer interests in locally-sourced ingredients and increasing number of microbreweries, hop production is emerging in many non-traditional U.S. growing regions like Virginia (VA). However, the lack of understanding on aroma chemistry of regional hops limited their prosperity. Moreover, suitable postharvest drying and packaging practices for VA hop producers are not available. This dissertation aims to address above issues by investigating the aroma chemistry of VA hops by varieties (Cascade, Chinook), growing locations (Meadowview/Petersburg/Blacksburg, VA), smaller-scale drying practices (oven drying, dehydrator drying, freeze drying) and packaging materials (PA/PE, OPP/Foil/PE, EVOH). Our efforts also extended to the novel application of hop-derived ingredients in non-beer drinks to promote value-added products. Solid phase microextraction and solvent-assisted flavor evaporation were applied for aroma extraction. Gas chromatography-mass spectrometry-olfactometry was used with stable isotope dilution analysis and standard addition method for accurate quantitation of aroma-active compounds. A total of 33 and 36 aroma-active compounds were identified in all fresh and dried hops, respectively. Geraniol, β-myrcene, linalool, methyl octanoate and trans-α-bergamotene were found to be the predominant compounds. Aroma profiles varied significantly with growing locations for both varieties. Individual aroma contents and total essential oil were the highest in dehydrator-dried hops, indicating the advantage of dehydrator-drying being a suitable practice to retain aroma power in hops for most smaller-scale producers in VA. Most volatile compounds in different packaged dried hops showed decreased concentrations over 8-month storage, but the variation was not statistically significant. Hop essential oil (HEO) microcapsules, manufactured by spray drying using modified starch CAPSUL® as the wall material, showed high flavor retention and controlled aroma release. The addition of HEO microcapsules significantly improved the aroma recovery and stability in hop tea. Our findings enhance the understanding of the aroma chemistry in regional hops as affected by multiple pre- and postharvest factors. The novel non-beer application of HEO was also successfully demonstrated. / Doctor of Philosophy / Hop (Humulus lupulus L.) is an essential raw material in beer brewing because it can provide beer products with unique flavor. With the growing "buy local" trend among consumers in recent years, hop production is moving to many non-traditional growing regions in the U.S. including Virginia. This resulted in an increasing number of local craft breweries operating on a smaller scale across the state. However, the aroma characteristics of Virginia-grown hops are unclear. Specific suggestions related to hop postharvest processing and storage are also unavailable for regional smaller-scale hop producers. Therefore, this study aims to study the aroma characteristics of Virginia-grown hops by varieties, growing locations, smaller-scale drying practices and packaging strategies. The novel non-alcoholic application of hop essential oil (HEO, mixture of many hop aroma compounds) was also demonstrated in hop tea. The results showed that both fresh and dried Virginia hops had a complicated profile of aroma compounds that primarily exhibited typical citrus, woody and fruity attributes. Both Cascade and Chinook varieties harvested from Meadowview showed significantly higher aroma contents than hops harvested from the other two locations in Virginia. Most aroma compounds in hops were better preserved by dehydrator drying than freeze an oven drying. No significant change was observed in aroma compositions from hops packaged in three different materials after storage. Finally, HEO particles with enhanced stability were prepared by engineering approaches, which were finally added to hop tea bags for the evaluation of aroma-intensifying effects and storage stability. The results indicated an overall desirable characteristic for the obtained HEO particles. The addition of HEO particles could significantly enhance the aroma stability of hop tea products during storage. Overall, the findings from this study enable a better understanding of flavor chemistry of regional hops from various origins and demonstrated a successful application of HEO particles as a flavoring agent in non-beer products.