Para comprender la composición de volátiles en guayaba fresca (Psidium guajava L.) Palmira ICA-1, en este estudio se plantearon diferentes métodos de extracción: la extracción líquido-líquido (L-L), la destilación-extracción simultáneas con disolvente (SDE), la microextracción en fase sólida del espacio de cabeza (HS-SPME) y la extracción con fluidos supercríticos (SFE). Se establecieron semejanzas y diferencias en la composición de acuerdo al método usado. Un total de 134 compuestos fueron identificados por los diferentes métodos de extracción, los ésteres, aldehídos y alcoholes fueron los más representativos. Se determinó la contribución sensorial mediante el cálculo de las unidades de olor (concentración del compuesto/umbral de olor) para los compuestos aislados por SDE, teniendo en cuenta el efecto de la temperatura durante el método de extracción. De igual forma se estudió la influencia del pH en la composición del aroma, 38 constituyentes volátiles se identificaron como enlazados a glicósidos. Igualmente, se realizó un estudio del mecanismo hidrodinámico (HDM) de la deshidratación osmótica con y sin pulso de vacío. Las mayores pérdidas de agua, ocurrieron con los tratamientos a 50 °C y con disoluciones osmóticas de 50 y 40 °Brix. La mayor transferencia de solutos ocurrió a 40 y 50 °C con vacío pulsante. Se demostró la influencia de los parámetros como temperatura, tiempo y concentración de la disolución osmótica en la cinética de la pérdida de agua, ganancia de solutos y evolución de la composición de volátiles en el producto osmodeshidratado. En general, las mayores pérdidas de volátiles ocurrieron a 50 ºC, mientras que las menores fueron a 30 y 40 ºC hasta 2 h con disolución osmótica a 30 y 40 ºBrix. Los ésteres fueron los compuestos que sufrieron mayores pérdidas durante el proceso de deshidratación osmótica a presión atmosférica y con pulso de vacío. / Quijano Celis, CE. (2011). ESTUDIOS DE LA COMPOSICIÓN DE VOLÁTILES Y SU EVOLUCIÓN DURANTE LA DESHIDRATACIÓN OSMÓTICA DE LA GUAYABA PALMIRA ICA-1 (Psidium guajava L.) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/13828 / Palancia

The impact of yeasts on food production, quality and safety is closely linked with their ecology and biological activities. Recently, as a consequence of the relationship between diet and health, yeasts are becoming relevant as new probiotics or for the production of bioactive compounds. In dairy products, yeasts play a key role in proteolysis, lipolysis and lactose fermentation during cheese ripening, promoting the development of sensory properties, particularly aroma. This thesis focuses on the yeast diversity in artisanal cheeses produced in the Natural Park Serra d¿Espadà (Castelló) from ewes¿ and goats¿ raw milk. Different molecular techniques have been employed in order to characterize yeast isolates. Moreover, the succession of species along the cheese ripening process was studied. The intraspecific variability of the most abundant identified species Debaryomyces hansenii and Kluyveromyces lactis was also assessed. Additionally, the potential of Kluyveromyces marxianus and K. lactis ß-galactosidases to synthetize prebiotic oligosaccharides from lactose and lactulose was tested. Finally, Kluyveromyces and Debaryomyces isolates were investigated for the production of cheese aromatic compounds. / Padilla López, B. (2014). Yeast diversity in artisanal cheeses: biotechnological applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/36065 / TESIS

El objetivo de este trabajo es caracterizar los compuestos volátiles responsables del aroma del vino elaborado a partir de la variedad Chardonnay, independientemente del origen geográfico y del estilo de vinificación. En una primera experiencia, la tipicidad « Chardonnay » de un grupo de 48 vinos (de los cuales 29 eran Chardonnay y 19 no) fue evaluada por un panel de expertos. Este estudio permitió la selección de un sub-grupo de vinos pertenecientes a dos niveles de tipicidad distintos: buenos ejemplos y malos ejemplos de vino Chardonnay. La segunda étapa del estudio consistió en seleccionar un método de extracción que diera lugar a un extracto representativo del aroma del vino de Chardonnay. Se evaluaron tres métodos de extractión: la extracción con diclorometano, el "salting-out" seguido de una destilación a vacio y el "salting-out" seguido de una extracción con diclorometano. Los extractos obtenidos fueron re-diluidos en una solución hidroalcohólica (12% vol.) para su comparacion sensorial con el vino original mediante un test de similitud. Los resultados mostraron diferencias significativas entre los tres métodos de extracción. El método de extración con diclorometano fue seleccionado por su buena compatibilidad con la cromatografia en fase gaseosa y por su facilidad de realización. Durante la tercera etapa se llevó a cabo una selección de los miembros del panel de olfactometria. Cuatro tests sirvieron para evaluar la habilidad de los candidatos a describir los olores, su repetibilidad en la deteccion y en la descripción, así como la presencia de hiposmias. Estos tests permitieron seleccionar 17 personas de entre 29 candidatos. La etapa sigiente consistió en el análisis olfactométrico propiamente dicho. Los 18 vinos elegidos fueron analizados por los 17 evaluadores seleccionados según el método de las frecuencias de detección. Setenta y dos zonas de olor fueron definidas. Gracias a una regresion PLS, se encontro una relación entre las notas de tipi / Ballester Pérez, J. (2004). Mise en évidence d'un espace sensoriel et caractérisation des marqueurs relatifs à l'arôme des vins issus du cépage Chardonnay [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1850 / Palancia

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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.

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.

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.

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.

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.

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.