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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.
171

Study of capsaicinoids and volatile compounds in Brazilian Capsicum chinense peppers = Estudo de capsaicinoides e compostos voláteis em pimentas brasileiras Capsicum chinense / Estudo de capsaicinoides e compostos voláteis em pimentas brasileiras Capsicum chinense

Sganzerla, Marla, 1986- 26 August 2018 (has links)
Orientador: Helena Teixeira Godoy / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-26T18:38:45Z (GMT). No. of bitstreams: 1 Sganzerla_Marla_D.pdf: 11263877 bytes, checksum: 32ac84fea7f4793868e0e58797653653 (MD5) Previous issue date: 2015 / Resumo: As pimentas do gênero Capsicum apresentam ampla aplicação em função dos atributos sensoriais de cor, pungência e aroma, decorrentes da presença de carotenoides, capsaicinoides e voláteis. No entanto, variações no conteúdo desses metabólitos secundários dependem de fatores como sazonalidade, ritmo circadiano, desenvolvimento da planta, características edafo-climáticas, ataque de patógenos. Neste estudo foi realizada a caracterização da composição de capsaicinoides e fração volátil de frutos de Capsicum chinense. A caracterização foi realizada através do uso de métodos analíticos cromatográficos (UPLC, UHPLC-MS e GC-MS). Com a execução desta pesquisa, foi possível caracterizar os frutos de C. chinense quanto à composição de metabólitos relacionados aos seus principais parâmetros de qualidade, fornecendo subsídios científicos para o conhecimento e melhoria da qualidade em termos de produção, aplicação industrial, compreensão de rotas metabólicas e melhoramento genético, além de gerar informações a respeito de substâncias potencialmente benéficas, devido a suas ações no organismo humano. Inicialmente foram desenvolvidos e validados os métodos, usando ferramentas estatísticas. De acordo com a etapa de otimização para a extração dos capsaicinoides, 100% de metanol combinado com o uso do banho de ultrassom por 10 minutos foram empregados. O método analítico desenvolvido através do uso de cromatografia em fase líquida de ultra eficiência permitiu a separação de 8 capsaicinoides em 4 minutos de análise cromatográfica e mostrou-se eficiente de acordo com a validação realizada. 9 acessos de pimentas C. chinense foram analisadas. Os teores de capsaicina e dihidrocapsaicina obtidos estavam nas faixas de 156 - 1442 ?g.g?1 e 26 - 478 ?g.g?1 (peso de fruto fresco), respectivamente. A caracterização do perfil de voláteis em pimentas 'Habanero', através do uso de HS-SPME (Headspace Solid-Phase Microextraction), foi realizada após etapa de otimização. Delineamento composto central e ferramenta de desejabilidade foram usadas a fim de avaliar, simultaneamente, duas respostas: soma total da área dos picos e número de compostos extraídos. O resultado maximizado para as duas respostas usando a fibra tripla (DVB/Car/PDMS) indicou o uso das condições de temperatura de extração de 40 °C e 30 min de extração. 82 compostos foram tentativamente identificados na fração volátil da pimenta 'Habanero' e os ésteres foram os compostos mais abundantes. O 2,3-dimetilciclohexanol e longifoleno foram identificados pela primeira vez em pimentas 'Habanero'. Além disso, pimentas 'Habanero' submetidas à diferentes condições de disponibilidade de água durante seu cultivo foram avaliadas quanto a composição de capsaicinoides e voláteis. Maiores quantidades de capsaicina e dihidrocapsaicina foram encontradas na pimentas maduras, alcançando valores entre as faixas de 2,85 - 3,33 mg.g-1 para capsaicina e 1,06 - 1,71 mg.g-1 para dihidrocapsaicina. Os teores de compostos voláteis totais foram maiores nas pimentas verdes (195,47 - 298,94 mg.kg-1), independente do tratamento de estresse hídrico que receberam. Os resultados obtidos com o PCA realizado possibilitaram, inicialmente, separar as pimentas 'Habanero' em função do grau de maturação. Enquanto, PCA aplicado, separadamente, nas pimentas verdes e maduras demonstrou uma separação evidente em função da data de colheita. Isso se deve ao fato de que influências do grau de maturação e época da colheita se sobressaíram no estudo. As pimentas foram agrupadas de acordo com o tratamento de irrigação recebido, mas para uma melhor compreensão dos efeitos dos tratamentos de estresse hídrico sobre a composição das amostras, seria necessário uma estratégia de estudo com monitoramento mais frequente dos frutos formados além de outras investigações sensoriais, como o uso de olfatometria. / Abstract: The Capsicum peppers are largely used due their sensorial properties as color, pungency and aroma. These characteristics occur by the presence of determinate classes of compounds including carotenoids, capsaicinoids and volatiles. These secondary metabolism derivatives compounds are influenced by two factors: genetics and plant-environment interactions and are susceptible to water availability conditions. This study had a proposal of the characterization of the capsaicinoids and volatile composition of the Capsicum chinense pepper fruits. The analysis were carried out by using of chromatographic methods (UPLC, UHPLC-MS and GC-MS). The results obtained and the characterization of the C. chinense fruits regarding the mainly compounds which influenced in the quality of the peppers provide the scientific subsidies for improvement of general quality, agricultural practices, industrial applications and breeding programs and also, the knowledge about substances potentially beneficial to the human organism. Initially, was developed and validated a fast, efficient and reproducible method to analyze capsaicinoids in Brazilian Capsicum chinense fruits by means the use of an optimization strategy to extracted the capsaicinoids. The extracts were obtained following the condition 100% of methanol and 10 min on ultrasound assisted extraction. The analytical method developed in an ultra high performance liquid chromatographic system coupled to a mass spectrometer permits the separation of 8 capsaicinoids in 4 min of time analysis expending only 2 mL of solvent as mobile phase. The method achieved was fully validated and show the effectiveness and satisfactory performance to answer the analytical needs of this research area. Different accessions of C. chinense fruits were analyzed, the contents of capsaicin and dihydrocapsaicin were in the range of 156 - 1442 ?g.g?1 and 26 - 478 ?g.g?1 of fresh fruit, respectively. Characterization of aroma profile of Capsicum chinense peppers 'Habanero' type, using Headspace Solid-Phase Microextraction (HS-SPME), was performed after an optimization step by GC-MS. Central composite design and Derringer's desirability function strategies were used for this optimization, in order to evaluate simultaneously the 'total sum peak areas' and 'number of extracted compounds' responses. The maximized results for both responses were obtained using PDMS/Car/DVB fiber, temperature of 40 °C and extraction time of 30 min. Eighty-two compounds were tentatively identified in the volatile fraction of the 'Habanero' pepper and the most abundant were hexyl isovalerate, cis-hexenyl isovalerate, hexyl 3-methylbutanoate, 3,3-dimethylcyclohexanol, longifolene, and 2-methyl-1-tetradecene. The compound 2,3-dimethylcyclohexanol and longifolene were reported for the first time in 'Habanero' pepper. In addition, Brazilian 'Habanero' peppers grown under different condition of water availability were evaluated regarding their capsaicinoids and volatiles composition. The higher values of capsaicin and dihydrocapsaicin were found in the mature peppers, achieving ranges from 2.85 - 3.33 mg.g-1 for capsaicin and 1.06 - 1.71 mg.g-1 for dihydrocapsaicin. Total volatile compounds presented higher values for the peppers in green stage of maturity with ranges from 195.47 - 298.94 mg.kg-1, whereas in the mature samples the range was from 68.74 - 118.50 mg.kg-1. According the results obtained with the PCA performed was possible separe the 'Habanero' peppers in function of the degree of maturity. While, PCA apllied, separately, for green and mature peppers showed a clear separation in function of the harvest date. This fact can be justified by the large influence of maturity degree and harvest date on the peppers composition. The peppers were clustered in function of the water availability treatments received, but to better understand the effects of water availability on the peppers composition, another strategy of evaluation, with more frequent monitoring would be interesting, as well as the inclusion of sensorial studies, as the olfactometry technique. / Doutorado / Ciência de Alimentos / Doutora em Ciência de Alimentos
172

Flavour combinations in meals : A systematic review of reasons for pairing flavours

Karlström, Daniel. January 2021 (has links)
No description available.
173

Charakterizace bylin rodu Plectrantus pro využití v potravinářství / Characterization of the genus Plectrantus for use in the food industry

Chmelová, Nikola January 2021 (has links)
The aim of this diploma thesis was to determine the optimal extraction conditions for obtaining an extract from the plant Plectranthus amboinicus. Plectranthus amboinicus is an aromatic herb of the Lamiaceae family containing a large number of bioactive compounds. Because of this, it has a number of biological effects – antimicrobial, anti-inflammatory, antioxidant, analgesic, etc. To maintain the maximum of sensory and nutritionally valuable components of P. amboinicus, a simple maceration of fresh chopped herb was chosen. Maceration was performed under the following conditions: 40 minutes at 40 ° C, solvent 40% ethanol, weight 20 g of herb per 100 ml of solvent. The extract prepared under these optimal conditions was comprehensively characterized in terms of the content of total polyphenols, their concentration was determined to 0,08 ± 0,02 mgGEA·ml-1, which corresponds to 0,40 ± 0,07 mgGEA·g-1 of the plant. The antioxidant activity of the extract was 241,24 ± 29,24 µgTEAC·ml-1 and the radical scavenging activity of ABTS•+ was determined to be 49,29 ± 5,97 %. The antimicrobial activity was verified by the agar well diffusion method. Two types of bacteria were selected for the determination – gram-positive Bacillus cereus, gram-negative Escherichia coli and yeast Candida glabrata. The results showed that the extracts have the highest antimicrobial activity against B. cereus. There were 64 volatile aromatic compounds identified in the extract, with monoterpenes and sesquiterpenes dominating. The obtained results confirm that P. amboinicus, or its prepared extract, has a good potential for use as a new and non-traditional flavor in various foods and delicacies, which can also increase their nutritional value.
174

Stanovení antimikrobiální a antioxidační aktivity vybraných bylinných extraktů / Determination of antimicrobial and antioxidant activity of selected herbal extracts

Čaková, Adriana January 2021 (has links)
Tetradenia spp. is herb naturally growing in Africa and is part of family called Lamiaceae. The herb is used in traditional medicine to cure malaria, angina or as treatment for tropical skin diseases. Maceration was chosen from number of extraction methods, to obtain bioactive compounds from this plant. Optimization was performed with aim to retrieve as much of bioactive compounds as possible. Optimal conditions chosen were: temperature 60 °C, extraction time 40 minutes, solvent 40% ethanol and solid-solvent ratio 1:5. In total 63 aromatic active compounds were found in optimal extract. Terpenes were the most abundant (88,60 %), from them oxygenated monoterpenes (55,65 %) and monoterpenes (29,52 %). Compounds with highest percentage quantity were camphor (51,76 %), cis--ocimene (8,17 %), 3-octyl acetate (7,71 %), trans--ocimene (6,76 %), -terpinene (4,93 %), o-cymene (3,81 %), terpinolene (1,33 %), limonene (1,33 %), camphene (1,19 %) and borneol (1,20 %). Further, total phenolic content was 0,31 ± 0,02 mgGAEml-1, which equals 1,52 ± 0,11 mgGAEg-1 of plant. Antioxidant activity was 417,56 ± 32,84 gTEACml-1 and percentage of radical scavenging activity ABTS•+ was 88,99 ± 7,00 %. Finally antimicrobial activity was determined against bacteria Bacillus cereus, Escherichia coli and yeast Candida glabrata. Against E. coli and C. glabrata there was no inhibition exhibited. Against B. cereus there was seen mild inhibition activity. The results confirm that Tetradenia spp. contain a number of interesting aroma active compounds, which shows antioxidant and antimicrobial activity. The herb has a good potential as natural source of nutritious and sensory active compounds to be used into various foods.
175

Výroba a charakterizace sýrů s přídavkem rostlinného extraktu / Production and characterization of cheese with the addition of plant extract

Kučerka, Štefan January 2021 (has links)
This master´s thesis deals with production and characterization of fresh cheese with addition of herb extracts, specifically extracts from Plectranthus amboinicus and Echinacea purpurea. The purpose of this thesis was to prepare samples with higher sensory quality and nutritional value. Produced cheeses were characterized in terms of volatile (aroma) substances, fatty acid content, total phenolic substances, antioxidant activity and sensory quality. Cheese sample with added extract from E. purpurea reached the highest value of total phenolic compounds (0,172 ± 0,019 mgGAEg-1 of cheese) and antioxidant activity (91,2 ± 2,2 gTEACg-1 of cheese). Cheese sample with added extract from P. amboinicus, compared to standard cheese sample (without added extract) also reached higher values of total phenolic compounds and antioxidant activity. 43 volatile (aroma) compounds were identified in both samples with added extracts (P. amboinicus, E. purpurea), in standard cheese sample it was 33. In sample with E. purpurea camphor was present in high amount (15,23 %) responsible for the camphor aroma, camphor was also identified in small amount in sample with P. amboinicus. Highest volatile matter content was identified in sample with P. amboinicus. Standard cheese sample was rated as the best from the sensory perspective. Addition of extracts had negative effect on color, taste, and aroma perception of cheese. Strongest herbal taste was identified in sample with E. purpurea, brownish color of this sample manifested in lower pleasantness of color. Obtained results show, that extract addition increases the nutritional value of cheese (higher content of aromatic substances and phenolic compounds, higher antioxidant activity), but lowers sensory quality and overall consumer acceptability.
176

Aplikace rostlinného extraktu do nečokoládových cukrovinek / Application of plant extract into non-chocolate sweets

Rychetský, Matěj January 2021 (has links)
This diploma thesis deals with the optimization of jelly candies production, application of herbal extract to produced candies, and subsequent characterization of produced samples in terms of volatile (aromatic) substances, total phenolic substances, antioxidant aktivity, and sensory quality. Optimization parameters – the amount of gelatin and the addition of citric acid, were selected based on the sensory analysis. Additions of 7,5 % gelatin and 2 % acid were proven to be optimal. The sources for the production of herbal extracts were the plants Aronia melanocarpa and Echinacea purpurea, which are known for their high content of bioactive substances. The further sensory analysis determined the optimal amount of extract added to jelly candies samples – in the case of chokeberry it was 4 % and in the case of echinacea it was 1 % of the extract. In the sample with chokeberry extract of optimal composition, ie 7,5 % gelatin, 2 % citric acid, and 4 % extract, 46 volatile substances were determined, of which nonanal (12,17 %) and thymol (8,70 %) were the most represented, the total polyphenol content was 472.88 ± 8.02 gGAEg-1 of the sample and the antioxidant activity was determined to be 828.99 ± 17.74 gTEACg-1 of the sample. The sample with echinacea extract of optimal composition, ie 7,5 % gelatin, 2 % citric acid and, 1 % extract, contained 56 volatile substances, the most represented being nonanal (12,08 %), thymol (6,19 %), and decanal (5,52 %). The total polyphenols in this sample were determined to be 291.09 ± 10.17 gGAEg-1 of the sample and its antioxidant activity was determined to be 850.91 ± 30.29 gTEACg-1 of the sample. Samples with the addition of chokeberry extract, which gave the confectionery a fruity, slightly sour taste and a pink to dark purple color, were considered more pleasant/acceptable; samples with echinacea had an herbal aroma and taste and orange color.
177

Biologicky aktivní látky aronie (Aronia spp.) / Biologically active substances of chokeberry (Aronia spp.)

Palkovská, Kateřina January 2021 (has links)
This master thesis deals with preparation of extracts from fruits of aronia, optimization of conditions for extraction and subsequent characteristics of the obtained optimal extract. In the theoretical part information about the botanical characteristics of Aronia melanocarpa and about its utilization are mentioned. Furthermore, the chemical composition of aronia fruits is described and the main biologically active substances contained in the plant are described. At the end of the theoretical part extraction and separation techniques, determination methods of antioxidant, antimicrobial activity and determination of aromatic active compounds are described. The experimental part describes the optimization of maceration so that the macerate contains as much polyphenolic substances as possible, as well as aromatic active substances. 40% ethanol, at a temperature of 60 ° C, with a weight solvent ratio of 1: 5, for 40 minutes proved to be optimal for the maceration of aronia fruits. The total polyphenol content of the optimal extract was determined to be 5237.2 ± 40.7 mgGAEkg-1 and the antioxidant activity by TEAC to be 512.5 ± 5.04 gml-1. 24 aromatic active compounds were identified in the extract, with the largest percentage being monoterpenes and aldehydes. Furthermore, it was found that the extract did not show antimicrobial activity against the microorganisms used (Bacillus cereus, Escherichia coli and Candida glabrata). The obtained results confirm that aronia extracts are an important source of many biologically active compounds and can be used in food as a natural source of nutritionally and sensory valuable substances.
178

Vliv aromaticky aktivních látek na senzorickou kvalitu nečokoládových cukrovinek / Influence of aroma compounds on sensory quality of sweets

Motúzová, Eliška January 2018 (has links)
This master´s thesis is focused on determination of aroma active compounds in non-chocolate sweets and their influence on sensory quality/flavour. The theoretical part describes production of non-chocolate sweets, characterizes aroma active compounds including allergenic ones, method for their determination by solid-phase microextraction and gas chromatography with mass detection. For experimental part were used as model samples gummy candies purchrased in regular market. Four flavors were used, specifically yellow (lemon), green (apple), red (strawberry) and orange (orange). The HS-SPME-GC-MS method was used to identify volatile aroma active compounds. To evalutate the sensory quality were used scales, a profile test, and a time course evaluation. Owerall 120 volatille compounds were identified including 8 allergens.
179

Srovnání obsahu aromaticky aktivních látek vybraných typů sýrů / Comparison of aroma active compounds of selected types of cheese

Brožová, Michaela January 2018 (has links)
This diploma thesis deals with the determination of aroma active substances in selected white mold cheeses, which are/are not awarded with the „Protected Designation of the European Union“ and their mutual comparison. In the theoretical part cheeses are characterised , including general production technology. The white mold cheeses are then described in detail. This is followed by the literary search dealing with the problematic of aroma active substances in cheeses. In conclusion of the theoretical part the method of their determination using solid phase microextraction and gas chromatography with mass detection is described. The SPME-GC- MS method was chosen for the experimental part of the determination of aroma active substances in selected white mold cheeses. A total of 12 cheeses were analyzed, of which 6 were Czech and Slovak and 6 were French with a protected designation of origin. The differences between individual samples were found in the number and type of the identified volatile compounds. A total of 78 volatiles were identified in selected cheeses, of which 20 were alcohols, 19 esters, 12 ketones, 11 acids, 4 sulfur compounds, 3 hydrocarbons, 3 lactones, 2 aldehydes, 2 phenols, 1 nitrogen compound. The cheeses were compared in terms of the identified compounds, and finally the results were statistically evaluated by the PCA method.
180

Srovnání aromatického profilu ovocných destilátů / Comparison of aroma profile of fruit distillates

Koubek, Miroslav January 2018 (has links)
This master thesis deals with the assessment of aroma active compounds in fruit spirits. In the theoretical part the production technology of fruit spirits from raw materials to final product is described. Furthermore, aroma active substances are characterized, and the method for their determination by solid phase microextraction and gas chromatography with mass spectrometry is described. The aim of the experimental part was the identification of volatile substances in different kinds of fruit spirits. Aromatic compounds were identified by the SPME-GC-MS. Domestic fruit spirits obtained from private growers were used as model samples. The differences in the number and type of volatile compounds were found between the samples. Overall 53 volatile compounds were identified. These were composed of 25 esters, 9 alcohols, 5 aldehydes, 4 alkenes, 2 ketones, 1 carboxylic acid and 7 other compounds.

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