Tesis por compendio / [ES] La industria alimentaria ha mostrado un enorme interés por desarrollar nuevos productos a base de fruta con el fin de satisfacer la demanda saludable y sostenible de productos alimentarios de los consumidores. En este sentido, un puré de naranja liofilizado podría representar una opción viable. La liofilización del puré da lugar a una torta que puede consumirse directamente como snack, o puede triturarse para obtener un polvo que puede utilizarse para una amplia gama de aplicaciones. Una optimización adecuada de las condiciones de liofilización podría ayudar a reducir su duración sin afectar a las características del producto final. Sin embargo, los alimentos deshidratados pueden presentar problemas de colapso estructural relacionados con su baja temperatura de transición vítrea. En este sentido, una técnica frecuente para la estabilización de estos productos deshidratados es la incorporación de biopolímeros de alto peso molecular. El objetivo de esta Tesis ha sido el diseño del proceso de liofilización para la obtención de un snack de naranja. Para ello se ha estudiado la influencia de diferentes combinaciones de biopolímeros en la estabilidad física del puré de naranja liofilizado (snack de naranja) y en la bioaccesibilidad in vitro de sus compuestos bioactivos. Asimismo, se ha evaluado su efecto en las propiedades de flujo en aire y de rehidratación del polvo de naranja. Se ha trabajado con diferentes combinaciones de goma Arábiga, maltodextrina, almidón sustituido por grupos octenil succínico, almidón nativo de maíz, fibras de guisante y de bambú. Los resultados mostraron la necesidad de incorporar estos biopolímeros para aumentar la actividad de agua crítica y el contenido de agua crítico para la transición vítrea, el cual se ha relacionado con la pérdida de la textura del snack. Si bien ninguna de las mezclas de biopolímeros fue mejor que las otras en higroscopicidad, carácter anti-plastificante, color y propiedades mecánicas del snack, la mezcla GA con FB fue la que mejoró la bioaccesibilidad de la vitamina C (VC) y de los compuestos fenólicos totales (TP). Además, esta misma combinación fue la que ofreció uno de los tiempos de mojado más cortos y una menor viscosidad del producto rehidratado, deseado para un producto tipo zumo. Por otra parte, se ha estudiado el impacto de las condiciones de liofilización en el consumo de energía del proceso y en la calidad del snack formulado con GA y FB. Las variables del proceso consideradas han sido la velocidad de congelación (convencional y abatidor), la temperatura de bandeja (30, 40, 50 ºC) y presión de trabajo (5, 100 Pa) durante el secado. Menor presión y mayor temperatura promovieron un ligero mayor secado de las muestras, obteniendo un producto más crujiente, con un color amarillo menos intenso, mejor preservación de VC y ß-caroteno (BC), y una reducción significativa, de hasta un 75%, en el consumo de energía total durante el secado, debido a la reducción del tiempo del proceso. La velocidad de congelación no tuvo impacto significativo sobre ninguna de las propiedades evaluadas. Por tanto, las condiciones recomendadas para el secado por liofilización son 5 Pa de presión y 50 ºC como temperatura de bandeja. Por último, se evaluó la estabilidad física y de los compuestos bioactivos y actividad antioxidante del snack almacenado en bolsas zip, a 4 y 20 ºC, durante 6 meses, simulando condiciones domésticas de almacenamiento. Como resultado, la muestra ganó cierta humedad, con la consecuente pérdida en porosidad y carácter crujiente a partir de los 2 meses. Asimismo, la luminosidad del snack almacenado a 20 ºC disminuyó pasados 2 meses, probablemente debido a las reacciones de pardeamiento, que incluyen la degradación de la VC (20%). BC sufrió una gran disminución, desde el inicio del almacenamiento y más cuanto mayor fue la temperatura. Por lo tanto, para este producto se recomienda un almacenamiento en refrigeración para una mejor preservación de los compuestos bioactivos. / [CA] La indústria alimentària ha mostrat un enorme interés per desenvolupar nous productes a base de fruita amb la finalitat de satisfer la demanda saludable i sostenible de productes alimentaris dels consumidors. En aquest sentit, un puré de taronja liofilitzat podria representar una opció viable. La liofilització del puré dona lloc a una coca que pot consumir-se directament com a snack, o pot triturar-se per a obtindre una pols que pot utilitzar-se per a una àmplia gamma d'aplicacions. Una optimització adequada de les condicions de liofilització podria ajudar a reduir la seua duració sense afectar les característiques del producte final. No obstant això, els aliments deshidratats poden presentar problemes de col·lapse estructural relacionats amb la seua baixa temperatura de transició vítria. En aquest sentit, una tècnica freqüent per a l'estabilització d'aquests productes deshidratats és la incorporació de biopolímers d'alt pes molecular. L'objectiu d'aquesta Tesi ha sigut el disseny del procés de liofilització per a l'obtenció d'un snack de taronja. Per a això s'ha estudiat la influència de diferents combinacions de biopolímers en l'estabilitat física del puré de taronja liofilitzat (snack de taronja) i en la bioaccessibilitat in vitro dels seus compostos bioactius. Així mateix, s'ha avaluat el seu efecte en les propietats de flux en aire i de rehidratació de la pols de taronja. S'ha treballat amb diferents combinacions de goma Aràbiga, maltodextrina, midó substituït per grups octenil succínic, midó natiu de dacsa, fibres de pésol i de bambú. Els resultats van mostrar la necessitat d'incorporar aquests biopolímers per a augmentar l'activitat d'aigua crítica i el contingut d'aigua crític per a la transició vítria, el qual s'ha relacionat amb la pèrdua de la textura del snack. Si bé cap de les mescles de biopolímers va ser millor que les altres en higroscopicitat, caràcter anti-plastificant, color i propietats mecàniques del snack, la mescla GA amb FB va ser la que va millorar la bioaccessibilitat de la vitamina C (VC) i dels compostos fenòlics totals (TP). A més, aquesta mateixa combinació va ser la que va oferir un dels temps de mullat més curts i una menor viscositat del producte rehidratat, desitjat per a un producte tipus suc. D'altra banda, s'ha estudiat l'impacte de les condicions de liofilització en el consum d'energia del procés i en la qualitat del snack formulat amb GA i FB. Les variables del procés considerades han sigut la velocitat de congelació (convencional i abatedor), la temperatura de safata (30, 40, 50 °C) i pressió de treball (5, 100 Pa) durant l'assecat. Menor pressió i major temperatura van promoure un lleuger major assecat de les mostres, obtenint un producte més cruixent, amb un color groc menys intens, millor preservació de VC i ß-caroté (BC), i una reducció significativa, de fins a un 75%, en el consum d'energia total durant l'assecat, a causa de la reducció del temps del procés. La velocitat de congelació no va tindre impacte significatiu sobre cap de les propietats avaluades. Per tant, les condicions recomanades per a l'assecat per liofilització són 5 Pa de pressió i 50 °C com a temperatura de safata. Finalment, es va avaluar l'estabilitat física i dels compostos bioactius i activitat antioxidant del snack emmagatzemat en bosses zip, a 4 i 20 °C, durant 6 mesos, simulant condicions domèstiques d'emmagatzematge. Com a resultat, la mostra va guanyar una certa humitat, amb la conseqüent pèrdua en porositat i caràcter cruixent a partir dels 2 mesos. Així mateix, la lluminositat del snack emmagatzemat a 20 °C va disminuir passats 2 mesos, probablement a causa de les reaccions de enfosquiment, que inclouen la degradació de la VC (20%). BC va patir una gran disminució, des de l'inici de l'emmagatzematge i més com més gran va ser la temperatura. Per tant, per a aquest producte es recomana un emmagatzematge en refrigeració per a una millor preservació dels compostos bioactius. / [EN] Food industries have showed a huge interest in developing new fruit-based products to satisfy the healthy and sustainable demand of food products by consumers. In this sense, offering a freeze-dried orange puree could represent a feasible option. Freeze-drying the puree results in a cake that can be consumed directly as a snack, or it can be crushed to obtain a powder that can be used for a wide range of applications. A suitable optimisation of the freeze-drying conditions could help to reduce its duration without affecting the characteristics of the final product. However, dehydrated foods may present problems of structural collapse related to its low glass transition temperature. In this sense, an approach for the stabilisation of dehydrated products is the incorporation of high molecular weight biopolymers. The aim of this Thesis has been the design of the freeze-drying process to obtain an orange snack. The influence of different combinations of biopolymers on the physical stability of the freeze-dried orange puree (orange snack) and on the in vitro bioaccessibility of its bioactive compounds has been studied. Their effect on the air flow and rehydration properties of an orange powder obtained after crushing the snack has also been evaluated. Different combinations of gum Arabic, maltodextrin, starch substituted with octenyl succinic groups, native corn starch, pea and bamboo fibres were used. The results showed the need to incorporate these biopolymers to increase the critical water activity and the critical water content for the glass transition, which has been related to the loss of snack texture. Although none of the biopolymer combinations was better than the others in terms of hygroscopicity, anti-plasticising character, colour, and mechanical properties of the snack, the GA mixed with FB was the one that improved the bioaccessibility of vitamin C (VC) and total phenolic compounds (TP). This same combination offered the shortest wetting times and a lower viscosity of the rehydrated product, which is desirable for a juice-type product. Also, the impact of the freeze-drying conditions on the energy consumption of the process and on the quality of the snack formulated with GA and FB has been studied. The process variables considered were freezing rate (conventional and blast freezer), shelf temperature (30, 40, 50 ºC) and working pressure (5, 100 Pa) during drying. Lower pressure and higher temperature promoted a slightly higher drying of the samples, which resulted in a crispier product, as well as a less intense yellow colour. However, at the sensory level, there was no significant preference for any of the samples processed under the different conditions studied. In addition, VC and ß-carotene (BC) were better preserved under these conditions, conditions which significantly reduced, up to 75%, the total energy consumption during drying, due to the reduction of the process time. The freezing rate had no significant impact on any of the properties evaluated. Therefore, the recommended conditions for freeze-drying to maximise the preservation of bioactive compounds, with a lower energy consumption, while providing a snack perceived as a crispy product by consumers, are 5 Pa pressure and 50 ºC as shelf temperature. Finally, the physical stability and the stability of bioactive compounds and antioxidant activity of the snack stored in zip bags at 4 and 20 ºC for 6 months, simulating domestic storage conditions, was evaluated. As a result, a certain moisture gain of the sample was observed, with a consequent loss in porosity and crispness after 2 months. Also, the luminosity of the snack stored at 20°C decreased after 2 months, probably due to browning reactions, including degradation of VC (20%). BC suffered a large decrease, from the beginning of storage and more so the higher the temperature. Therefore, refrigerated storage is recommended for better preservation of the bioactive compounds of this product. / Silva Espinoza, MA. (2021). Design of the process of obtaining a freeze-dried orange puree. Formulation, freeze-drying variables, and storage conditions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/170354 / Compendio

Made available in DSpace on 2014-08-20T13:44:42Z (GMT). No. of bitstreams: 1 dissertacao_lilian_tunes.pdf: 3629520 bytes, checksum: c63e3ee7e985806eda7edeb195ebba76 (MD5) Previous issue date: 2009-01-17 / The barley culture (Hordeum vulgare L.) for the beer production it is constituting in one of the more promising and safe agricultural businesses of the country, because it already comes linked to the commercialization process, by previous contract between the producer and the malt industry. In view of this and of the economical answer in relation to other winter cultures, many producers show interest in the inclusion of the barley in their production systems. The objective of this work was to evaluate physiologic attribute of quality about different harvesting periods of barley seeds and during the storage. The seeds used were of the cultivars MN 721 and Scarlett. Harvesting was accomplished when the plants were with 118, 129 and 140 days after the seeding. The seeds were dried in an oven with forced air circulation, until reaching 13% of moisture and then, stored in a cold room and out of the room. After harvesting different methods were tested for overcoming dormancy. The seeds were put for the germination tests, seedling length, mass dry weight, tetrazolium, accelerated aging, seed emergence, electrical conductivity, weight of a thousand seeds, hectolitric weight and also isoenzimatic diferentitation [malato desidrogenase (MDH), alcohol desidrogenase (ADH), acid fosfatase (FAC), glutamate oxalacetato transaminase (GOT) and esterase (EST)]. The results obtained showed that the intensity of dormancy and harvest periods interferes, directly, in the efficiency of the treatments used for overcoming dormancy. Harvesting should be accomplished when the seeds reach the humidity between 26 and 18%. The weight of a thousand seeds influences in a positive way, demonstrating that heavier seeds presented better quality than the light ones. The hectolitric weight, germination and viability tend to decrease as the harvesting period is delayed. There are variations in the pattern of expression of the enzymes EST, ACP, MDH, ADH and GOT between the seeds and seedlings. In the germination process the enzyme EST showed difference between cultivars MN 721 and Scarlett, however it had small variation in the different harvesting periods. In the germination process the enzyme GOT showed variation in the intensity of bands in the different moisture percentages. During storage it was evaluated the physiologic quality of the seeds, at the 3rd and the 6th months, analyzing two atmospheres (cold room and natural conditions). The results were that, the capacity of conservation of barley seeds it is just according to its initial quality. / A cultura de cevada (Hordeum vulgare L.) para a produção de cerveja vem se constituindo em um dos negócios agrícolas mais promissores e seguros do país, pois já vem vinculado ao processo de comercialização, mediante contrato prévio entre o produtor e a indústria de malte. Em vista disto e da resposta econômica em relação a outras culturas de inverno, muitos produtores mostram interesse na inclusão da cevada em seus sistemas de produção. O objetivo do trabalho foi avaliar atributos fisiológicos de qualidade de sementes de cevada sobre diferentes épocas de colheita e durante o armazenamento. Foram utilizadas sementes das cultivares MN 721 e Scarlett. As sementes foram secadas em estufa com circulação de ar forçado, até atingir 13% de umidade e então, armazenadas em câmara fria e seca e ambiente natural. Após a colheita foram testados diferentes métodos para a superação de dormência. As sementes foram avaliadas pelos testes de germinação, comprimento de plântulas, massa seca, tetrazólio, envelhecimento acelerado, emergência de plântulas, condutividade elétrica, peso de mil sementes, peso hectolítrico e também diferenciação isoenzimática [malato desidrogenase (MDH), álcool desidrogenase (ADH), fosfatase ácida (FAC), glutamato oxalacetato transaminase (GOT) e esterase (EST)]. Dos resultados obtidos, a intensidade da dormência e época de colheita das sementes de cevada interfere, diretamente, na eficiência dos tratamentos utilizados para sua superação. A colheita da cevada deve ser realizada quando as sementes atingirem a umidade entre 26 e 18%. O peso de mil das sementes influi de maneira positiva, demonstrando que sementes mais pesadas apresentaram melhor desempenho que as leves. O peso hectolítrico, a germinação e a viabilidade tendem a decrescer com o processo de retardamento da colheita. Há variações no padrão de expressão das enzimas EST, ACP, MDH, ADH e GOT entre as sementes e as plântulas. No processo de germinação a enzima EST apresentaram diferença entre as cultivares MN 721 e a Scarlett, no entanto teve pequena variação nos diferentes períodos de colheita. No processo de germinação a enzima GOT apresentou variação na intensidade de bandas nas diferentes percentagens de umidade. Durante o armazenamento foram avaliados a qualidade fisiológicas das sementes, por um período de 3 e seis meses, analisando dois ambientes (câmara fria e seca e ambiente em condições naturais). Os resultados encontrados foram que, a capacidade de conservação de sementes de cevada relaciona-se com a sua qualidade inicial.

Indiana University-Purdue University Indianapolis (IUPUI) / Short tandem repeat (STR) analysis is currently the most common method for processing biological forensic evidence. STRs are highly polymorphic and allow for a strong statistical power of discrimination when comparing deoxyribonucleic acid (DNA) samples. Since sample testing and court proceedings occur months, if not years apart, samples must be stored appropriately in the event additional testing is needed. There are generally accepted methods to store DNA extracts long-term; however, one universally recognized method does not exist. The goal of this project was to examine various methods of storage and make recommendations for a universal storage method that maintained DNA integrity over time. Four variables were evaluated: storage buffer, storage temperature, initial storage concentration and the effects of repeated freeze-thaw cycles. DNA quantity was assessed using real-time polymerase chain reaction and DNA quality was evaluated using STR genotyping. Overall, the Tris-EDTA (TE) buffer outperformed nuclease free water as a long-term storage buffer for DNA extracts. Stock tubes stabilized concentration better than single use aliquots when eluted with TE while tube type was not significant when water was the buffer. For samples stored in TE, temperature had no effect on DNA integrity over time, but samples stored in water were largely affected at room temperature. Additionally, the greater the initial DNA concentration, the less likely it was to degrade in water. As a result of this research, DNA extracts from forensic samples should be stored long-term in TE buffer with a minimum concentration of 0.1 ng/μL. When water is the buffer, frozen storage is recommended.

MSCAGR (Plant Production) / Department of Plant Production / Chickpea (Cicer arietinum L.) is an excellent utilizer of residual soil moisture in agricultural ecosystems. However, its seed quality and hence reproduction is constrained by water stress, seed size and storage conditions. This study was carried out at the University of KwaZulu- Natal (UKZN), Pietermaritzburg Campus. It was conducted to evaluate the performance of chickpea genotypes (Desi-K, Saina-K and ICCV-K) with different seed sizes on seedling emergence (i), seed ageing effect on seed quality and imbibition of genotypes produced under water stressed and non-stressed conditions (ii), and (iii) the effect of water stress during seed development on sugars and protein accumulation, germination and seed vigour. Pot experiments were conducted under glasshouse / tunnel conditions at the Controlled Environment Facilities (CEF). The experiment for objective 1 was laid out as a single factor in completely randomized design (CRD). Data on emergence rate, final hypocotyl and complete emergence was collected. The small seeded Desi-K showed higher and faster emergence compared to medium sized Saina-K and large seeded ICCV-K. In the experiment of the second objective, seeds of the three genotypes were first obtained by production under water stressed and non-stressed growing conditions. They were then aged for 0, 1, 3, 5, or 7 days at 41 ºC and 100% relative humidity to form a 2 x 3 x 5 (water levels x genotypes x ageing) factorial design. Data was collected on germination percentage (GP), mean germination time (MGT), electrical conductivity (EC), tetrazolium chloride test (TZ) and imbibition weight. Seed ageing caused progressive loss of seed viability and vigour in all genotypes, which resulted in lower GP, delayed MGT, reduced TZ staining, cell death and high solute leakage from the seeds produced under the two water regimes. However, the effect was more severe under water stressed conditions. In the experiment for objective 3, seeds of all three genotypes were larger when grown under non-stressed condition compared to those under water stressed condition. These larger seeds had higher seed viability and germination percentage but lower electrical conductivity and mean germination time. Stressed seeds had higher soluble sugars than non-stressed seeds. It was deduced that irrigation during seed development reduces the final sugars and protein content but increases the seed size and physiological quality parameters allied to production of chickpea. Therefore, water provision to chickpea crop is critical during seed development. / NRF