Nine Virginia soybeans grown in a single location were compared for their antioxidant properties and isoflavone profiles. The extracts were evaluated for their total phenolic contents (TPC), Oxygen Radical Absorbance Capacity (ORAC), and DPPH™ radical scavenging activities. In order to evaluate efficient preparation methods for soybean antioxidants, three Virginia-grown soybeans were extracted using different extraction strategies. The extraction techniques included soxhlet extraction, conventional solvent extraction, and ultrasonic-assisted extraction (UAE) with 5 different common solvent systems including 50% and 80% aqueous acetone, 50 and 70% aqueous ethanol, and 80% aqueous methanol. The TPC in the soybean extracts and isoflavone compositions were significantly different among cultivars. Malonylgenistin was the major isoflavone in all soybean seeds, accounting for 75-83% of the total measured isoflavones. The V01-4937 variety had the highest total isoflavone and malonylgenistin contents, followed by V03-5794. The antioxidant activities of the soybean extracts were also significantly different. Overall, the V01-4937 soybean was the variety that stood out from the other tested Virginia soybeans because it had the highest TPC, ORAC value, and isoflavone contents as well as the second highest DPPH™ scavenging activity. Ultrasonic treatment improved the extraction of soybean phenolics by more than 50% compared to solvent alone. The UAE with 50% aqueous acetone was the most efficient for extraction of phenolic compounds in the soybean seeds. The conventional and UAE with 70% aqueous ethanol extracts had the highest ORAC values, while the soxhlet methanol extracts had the highest DPPH™ radical scavenging activities. Our results suggest that different extraction technologies have a remarkable effect on soybean antioxidant estimation and the UAE is more appropriate for soybean phenolic extraction because it is less time and solvent consuming than the conventional solvent and soxhlet extractions. The V01-4937 soybean with the highest TPC was evaluated for its antioxidant activity and isoflavone contents in an in vitro digestive system. After gastrointestinal digestion, soybean extracts contained higher TPC and ORAC values than cooked soybean (before digestion) but they were relatively low in DPPH™ radical scavenging capacity. The glucosides, daidzin, genistin, and malonylgenistin showed stability during simulated digestion with 83.3 %, 59.4 %, and 10.7 % recovery, respectively. Aglycones, including daidzein and genistein, were recovered at 37 % and 73.7 %, respectively, after in vitro digestion. In this study, daidzin was the most stable and bioaccessible isoflavone determined using the in vitro digestive system. Among the aglycones, genistein was more stable and bioaccessible than daidzein after digestion. In conclusion, soybean antioxidant activities were different among cultivars and efficient extraction for TPC was found using UAE with 50% aqueous acetone. Furthermore, antioxidant activities were stable during digestion and genistein, within aglycones tested, was the most stable and bioaccessible compound following in vitro digestion. This information may provide manufacturers or researchers information required to develop food or nutraceutical products processed for better bioaccessibility of soybean bioactive components. / Ph. D.

Studies were conducted to determine the role of bioflocculation in the activated sludge unit processes. Laboratory and full-scale studies revealed that bioflocculation is important in determining settling, dewatering, effluent and digested sludge properties (activated sludge properties) and may be vital to the function of all processes related to the above properties. In these studies, it was shown that divalent cations such as calcium and magnesium improved activated sludge properties, whereas monovalent cations such as sodium, potassium and ammonium ions were detrimental to these properties. The divalent cations promoted bioflocculation through charge bridging mechanisms with negatively charged biopolymers (mainly protein and polysaccharide). It was found that oxidized iron plays a major role in bioflocculation and determination of activated sludge properties through surface interactions between iron and biopolymers. Oxidized iron was effective in removing colloidal biopolymers from solution in coagulation and conditioning studies. The research included experiments evaluating effects of potassium and ammonium ions on settling and dewatering properties; effects of magnesium on settling properties; effects of sodium, potassium, calcium and magnesium on effluent quality; effect of solids retention time on effluent quality; and evaluation of floc properties during aerobic and thermophilic digestion. A floc model is proposed in which calcium, magnesium and iron are important to bioflocculation and the functionality of aeration tanks, settling tanks, dewatering equipment and aerobic or anaerobic digesters. It is shown that activated sludge floc properties affect wastewater treatment efficiency. / Ph. D.

Aedes aegypti mosquitoes are found globally and also act as the primary vector of Zika, dengue, and Chikungunya viruses, for which there are limited treatment options and no vaccines available. The use of insecticides as the main control strategy against diseases transmitted by this mosquito, is increasingly challenged by emerging resistance. Thus, there is a dire need for the development of novel approaches informed by an improved understanding of mosquito biology, to control mosquito populations and, ultimately, disease transmission. Rhythmic biological processes in mosquitoes help optimize resource exploitation by coordinating behaviors and physiology with fluctuating environmental conditions. Such synchronization enables organisms to adjust their physiology, metabolism, and behavior to predictable external cycles. In mosquitoes, circadian rhythmicity has been demonstrated in their biting and oviposition behavior, as well as their locomotor activity. However, little is known regarding how responses to long-range host cues are modulated by the circadian system. Here we show that both antennal sensitivity and olfactory behavior are time-of-day and odor-specific in Ae. aegypti females. Global transcriptomic analysis in whole heads of Ae. aegypti females reveal chemosensory genes differentially expressed throughout the day, providing insight into the molecular mechanisms behind daily variations in olfactory sensitivity and behaviors. We additionally show an odor-induced activation of mosquito behavior. Mosquito locomotion and behavior are also mediated by physiological state, and activity decreases after blood-feeding. Since the central clock components have been shown in other organisms to be redox-sensitive, we explored the role that diet heme plays in mediating behavioral changes following blood ingestion using artificial blood diets. We found that the transcription of the timekeeping gene period is reduced in the head immediately after feeding on a meal containing hemoglobin, but peripheral period transcription is reduced throughout the course of digestion following ingestion of a protein meal independent of hemoglobin inclusion. Overall, our results show that Ae. aegypti behavioral rhythms mediated by rhythmic gene expression are plastic and susceptible to external host cues and host blood digestion. This work can be leveraged for future studies investigating mosquito host-seeking and blood digestion to identify novel targets for vector control. / Doctor of Philosophy / Female mosquitoes rely on blood-feeding in order to produce eggs, but can unfortunately act as vectors of disease if they transmit pathogens when biting. Insecticides are currently our strongest main tool for controlling mosquito disease vectors such as Aedes aegypti, the yellow fever mosquito. However, increasing cases of insecticide resistance present new challenges in vector control, and new strategies to prevent vector-borne disease are needed. The Ae. aegypti mosquito is found globally and transmits Zika, dengue, and Chikungunya viruses, for which there are limited treatment options and no vaccines available. Mosquitoes exhibit rhythms in their gene expression and behaviors such as biting and activity patterns, in order to optimize energy efficiency and coordinate their biology and behaviors with daily fluctuations in the environment. However, it is unknown how their responses to human host odor cues are modulated by their central timekeeping system in the brain. Mosquitoes primarily find a human host via their sense of smell, or olfaction. Odor molecules in the air, emitted by humans, can be detected by mosquitoes' antennae. Here we show that both antennal sensitivity and behavioral responses to odors are time of day and odor-specific in Ae. aegypti females. We quantified gene transcripts in whole heads of Ae. aegypti females as a measure of gene expression, which revealed that genes involved in odor detection are expressed differently throughout the day, providing insight into the molecular mechanisms behind behavioral observations. We also show that mosquito behavior can be activated by odor exposure, and that their behavioral patterns can be influenced for multiple days following exposure. Mosquito behavior is also influenced by blood-feeding, which reduces mosquito activity and flight. Time-keeping genes in the fly brain have been shown to be sensitive to oxidative stress. Blood contains the protein hemoglobin, which can lead to oxidative stress when digested. Using artificial blood diets that allowed us to include or exclude hemoglobin in the meal, we found that the transcription of the timekeeping gene period is reduced in the head immediately after feeding on a diet containing hemoglobin, but is reduced in the rest of the body throughout the course of digestion following ingestion of a protein meal, whether hemoglobin was included or not. This work can be leveraged for future studies investigating mosquitoes' rhythms in host-seeking and blood digestion to identify new effective targets for vector control.

Various combinations of multi-stage thermophilic and/or mesophilic anaerobic sludge digestion systems were studied to evaluate their solids reduction, odor generation after centrifugal dewatering and indicator organism reduction in comparison to single-stage thermophilic and/or mesophilic anaerobic digestion systems. Pre-aeration of sludge in a thermophilic temperature was also tested followed by single or multi-stage anaerobic digestion systems. It was found that multi stage systems were capable of greater solids removal and placing thermophilic system in multi stage system enhanced indicator organism destruction below EPA Class A biosolids requirement. However, all the digestion systems in the study showed less than 3 log reduction of indicator organism DNA/g solids, which was much smaller than indicator organism reduction measured by standard culturing method. It was also found that the thermophilic anaerobic digestion system could increase organic sulfur-based odors from dewatered biosolids while placing a mesophilic digester reduced odors. It was exclusively observed from sludges containing high sulfate such as ones in this study. A combined anaerobic and aerobic sludge digestion system was also studied to evaluate their solids and nitrogen reduction efficiencies. The aerobic digester was continuously aerated to maintain dissolved oxygen level below 1 ppm and intermittently aerated. It was found that 90 % or more nitrogen removal was possible at the aerobic SRT greater than 3 days and the optimum aeration ratio could be determined. / Ph. D.

Addition of iron to sewer lines for chemical phosphorus removal is widely practiced around the world. However, high dosage of iron may prove detrimental to the anaerobic digestion process and also lead to higher organic sulfur odors and deteriorating biosolids quality. The following research focuses on finding an alternative to the use of iron in wastewater systems by comparing the roles of iron and magnesium on mesophilic anaerobic digestion, the digested effluent characteristics and odors in biosolids. Three anaerobic digesters were operated, one serving as a control with no additives, and the other two having known doses of iron and magnesium added. Comparison of the effluent characteristics revealed an improvement in the overall performance of the magnesium amended digester (in terms of pH, solids and COD reduction, alkalinity and gas production) over the other two reactors, suggesting the benefits of magnesium addition. Both iron and magnesium were found to be effective in achieving high levels of phosphate removals and reducing nuisance odors in dewatered sludge cakes. / Master of Science

Anaerobic digestion has been the preferred method for reducing and stabilizing waste sludge from biological wastewater treatment for over a century; however, as sludge volumes and disposal costs increase, there has been a desire to develop various methods for reducing the volume of sludge to be treated, improving the performance of the digesters, and increasing the energy value of the sludge. To this end, there have been numerous pretreatment and side-stream systems studied and developed over the past several decades with the overall goal of reducing the volume of biosolids to be disposed of in landfills or by land application. These technologies can be broken into four large groups: mechanical, thermal, chemical and biological, although there is often overlap between groups. This research approached the evaluations of these technologies through several methods in the hopes of developing effective tools for predicting the performance of each technology. Batch digestion studies mimicking several of these treatment methods and extensive analytical work on samples from full-scale installations were conducted to determine the effectiveness of each technology. From these studies a simple batch digestion methodology was developed to analyze the effectiveness of the Cannibal solids reduction process on wastewater streams that have never been exposed to it. Batch digestion of sludges pretreated with ozone, mechanical shear and sonication provided insight into the effectiveness of each technology. Extensive analytical work on samples collected from full-scale installations of thermal hydrolysis, mechanical shear and the Cannibal process provided some insight into the workings of each process and potential leads as to how to further characterize and evaluate each process. / Master of Science

Autothermal thermophilic aerobic digestion (ATAD) of sludge has been used to produce class A biosolids. With stringent EPA guidelines, more and more municipalities are looking to use this process for digestion of sludge. However the large polymer costs associated with dewatering these sludges has made the use of this technology unfavorable. Several studies have been conducted in the past which have looked into the mechanism leading to such a poor dewatering of sludge. Some of these studies have attributed the release of protein and polysaccharide during the high temperature digestion to be responsible for the poor dewatering. However the exact mechanism leading to the poor dewatering is still not totally clear. Laboratory scale studies were conducted to evaluate the mechanism leading to the poor dewatering of these sludges and also to be able to economically condition these sludges. ATAD sludge samples were collected from ATAD processing facilities in Ephrata, PA, Cranberry, PA, Titusville, FL and College Station, TX. The research included experiments evaluating the protein and polysaccharide concentrations in solution, cations and anions, iron and aluminum, zeta potential and capillary suction time. It was found that during digestion large amounts of protein and polysaccharide were released which were in the colloidal range, and the dewatering of each of these sludges became poorer as the amount of protein and polysaccharide in the solution increased. The release of protein and polysaccharide was related to the monovalent to divalent cation ratio and the iron and aluminum concentration in the sludge. Also during the digestion process, the pH of the sludge increased appreciably and the divalent cations precipitated out. The zeta potential of the ATAD digested sludge was also found to be positive. Different chemical coagulants were used to condition the sludge, but even with high polymer doses the dewatering of the sludge was not satisfactory. A combination of iron (or cationic polymer) followed by anionic polymer was found to improve the dewatering to a desired level. The use of this combination of sludge conditioning also provides an economical solution to the problem of dewatering. The role of iron in improving the dewatering of the sludges was found to be important, with the sludge dewatering being better for sludges with a high iron content. The combination of high pH, divalent cation precipitation, iron deficiency and biopolymer release all contribute to the poor dewatering of ATAD sludge. / Master of Science

Food waste is a desirable feedstock for anaerobic digestion because it is high in moisture and is an easily degradable material. However, mono-digestion of food waste often fails due to the accumulation of volatile fatty acids. Supplementing trace elements is one strategy to combat this issue. This study examined the effect of supplementing trace elements (iron, nickel, selenium, molybdenum, magnesium, zinc, calcium, copper, manganese, cobalt) on the methane yield and organic waste destruction of anaerobically digested food waste. Methane yield of food waste with and without the inorganic salt trace element was determined by the gas density-based biomethane potential method at mesophilic (37°C) conditions over 30 days. The three treatments were inoculum only, food waste and inoculum, and food waste and inoculum with an added trace element solution. There was no significant difference between treatments in terms of waste stabilization (percent volatile solids, total solids, and total chemical oxygen demand reduction) between treatments. The average cumulative biogas produced was 41% higher, and the average total cumulative methane produced was 23% higher in the treatment with the trace element supplement. Mean methane yield was not different (p > 0.05) between treatments over the 30 days, and there was no difference (p > 0.05) in biomethane potential between treatments. In addition, greenhouse gas reduction potential was estimated from food waste streams in Montgomery, VA using anaerobic digestion. The purpose of this work was to (1) estimate the total mass of food waste produced in Montgomery, VA in a year, (2) use the results from the biomethane potential analyses to inform the sizing of a theoretical community digester in Montgomery, VA, and (3) estimate the greenhouse gas reduction potential of anaerobically digesting the food waste instead of sending it to landfill. Greenhouse gas reduction was calculated using the Climate Action Reserve Organic Waste Digestion Project Protocol guidelines. The greenhouse gas reduction potential was estimated as 6,532 tonnes of carbon dioxide equivalent per year (tCO2e/year), with approximately 693 m3 methane produced per day. In one year, the digester would generate an estimated 7370 kWh of energy which has the potential to power 149 homes for a year in Montgomery, VA. In addition, 4130 tonnes/year of composted digestate would be available as fertilizer for surrounding farms. / Master of Science / Currently, about one-third of the entire U.S. food supply is lost or wasted. A large portion of that food waste is sent to landfills, where it produces methane, a greenhouse gas. Instead, food waste can be broken down to produce biogas during anaerobic digestion. Anaerobic digestion is a process in which microorganisms break down organic materials in the absence of oxygen to produce biogas and digestate, a material used as a soil amendment or fertilizer. However, anaerobically digesting food waste often leads to process instability and failure due to a buildup of undesirable intermediates. Microorganisms in anaerobic digestion require certain trace elements (i.e., iron, copper) that food waste often lacks; therefore, supplementing key trace elements may improve the anaerobic digestion of food waste. This research aimed to assess the effect of supplementing key trace elements (iron, copper, zinc, calcium, magnesium, nickel, manganese, selenium, molybdenum, cobalt) on organic matter degradation and methane yield. Methane yield of food waste with and without the inorganic salt trace element was determined by the gas density-based biomethane potential method at mesophilic (37°C) conditions over 30 days. The average cumulative biogas produced was 41% higher, and the average total cumulative methane produced was 23% higher in the bottles containing a trace element supplement. No significant difference was seen in the two groups when comparing organic matter degradation. These results demonstrate that supplementing trace elements can improve biogas and methane production. Greenhouse gas reductions from anaerobically digesting food waste instead of sending it to landfills were determined for Montgomery, VA. The results from the biomethane potential test informed the design of a theoretical community digester. Greenhouse gas reduction was calculated using the Climate Action Reserve Organic Waste Digestion Project Protocol equations. The greenhouse gas reduction was determined as 6,532 tonnes of carbon dioxide equivalent per year (tCO2e/year). The digester would produce approximately 693 m3 methane/day, which has the potential to power 149 homes for a year in Montgomery, VA. In addition, 4130 tonnes/year of compost would be produced and available as a fertilizer for surrounding farms.

Tesis por compendio / [EN] The present PhD thesis, entitled "Encapsulation of folic acid in silica porous supports: a nutritional and technological approach", focuses on the development of new smart systems for the controlled delivery of folic acid for nutritional applications. The first part of the thesis shows folic acid encapsulation in polyamines-functionalized silica porous matrices from a nutritional approach. The first part evaluates not only the influence of the loading method and the type of silica support employed (MCM-41, SBA-15, UVM-7 and Hollow Silica) on the efficacy of folic acid encapsulation, but also the influence of the morphology and porous system on the folic acid delivery profile from different supports. Folic acid release studies from different supports with various pH values have demonstrated that the designed systems are capable of smartly modulating the delivery of the folic acid dependent on the pH of the medium (inhibition of the release at an acidic pH -stomach-, controlled release at a neutral pH -intestine-). This capacity makes these developed delivery systems an excellent alternative to direct fortification to successfully modulate the bioaccessibility of folic acid along the gastrointestinal tract. The stability of the supports during an in vitro digestive process was evaluated, and demonstrated that not only small particles can be attacked during the digestion process, but also the functionalization with organic molecules, which act as molecular gates, prevents this attack. Finally, the cell viability studies carried out with four different cell lines revealed that neither the supports nor their degradation products caused any specific toxicity during the in vitro digestive process. The second part evaluates the influence of adding different silica supports to two food matrices: gelatin gels and yoghurts. This technological approach enabled us to know that the capacity of these smart systems to deliver folic acid in a controlled manner during an in vitro digestive process is mantained even after their incorporation in stirred yoghurt. The effect of the matrices on the gel's physical properties depends on the particle size, functionalization and concentration. Finally, this thesis tested that the optimization of folic acid loading, achieved in the first part of the thesis, allowed the fortification of yoghurt with 100% of the recommended daily allowance of folic acid with a very low amount of the system. This fortification affected neither the physico-chemical properties of the yoghurt, nor bacterial viability. In summary, it was concluded that the present thesis globally deals with folic acid encapsulation in silica porous matrices to be used in nutritional and food applications, which include the optimization of loading, release studies at diferent pH, in vitro digestions, stability studies of the employed matrixes, biocompatibility studies, and studies into the influence of their addition to food matrixes. The obtained results positively exhibit that the developed smart folic acid delivery systems open up a new way of fortifying food without endangering the properties of the food to which they are added. / [ES] La presente tesis doctoral que lleva por título "Encapsulación de ácido fólico en soportes porosos de óxido de silicio: una aproximación nutricional y tecnológica" está centrada en el desarrollo de nuevos sistemas inteligentes de liberación controlada de ácido fólico para aplicaciones nutricionales. La primera parte de la tesis muestra la encapsulación de ácido fólico en matrices porosas de óxido de silicio funcionalizadas con poliaminas desde una aproximación nutricional. En ella se ha evaluado la influencia del método de cargado y del tipo de soporte de óxido de silicio utilizado (MCM-41, SBA-15, UVM-7 y Hollow Silica) en la eficacia de encapsulación de ácido fólico. En esta primera parte, también se ha evaluado la influencia de la morfología y el sistema de poros de los diferentes soportes en el perfil de liberación del ácido fólico desde los mismos. Los estudios de liberación de ácido fólico desde los diferentes soportes a diferentes valores de pH han demostrado que los sistemas diseñados son capaces de modular inteligentemente la liberación de ácido fólico en función del pH del medio (inhibición de la liberación a pH ácido -estómago-, liberación controlada a pH neutro -intestino-). Esta capacidad convierte a los sistemas liberación desarrollados en una alternativa excelente a la fortificación directa para modular exitosamente la bioaccesibilidad del ácido fólico a lo largo del tracto gastrointestinal. Por otra parte, se ha evaluado la estabilidad de los soportes durante un proceso de digestión in vitro, demostrando que si bien algunos soportes pueden ser atacados durante la digestión, la funcionalización con moléculas que actúan como puertas moleculares previene este ataque. Por último, los estudios de viabilidad celular llevados a cabo en cuatro tipos de líneas celulares demuestran que ni los soportes, ni los productos de degradación de los mismos durante el proceso de digestión in vitro promueven ningún tipo de toxicidad inespecífica. En la segunda parte se ha evaluado la influencia de la adición de diferentes soportes de óxido de silicio a dos matrices alimentarias, geles de gelatina y yogures. Esta aproximación tecnológica ha permitido conocer que la capacidad de estos sistemas inteligentes para liberar controladamente el ácido fólico a lo largo de un proceso de digestión in vitro se mantiene incluso tras su incorporación en yogures batidos. Por otra parte, se ha comprobado que el efecto de las matrices sobre las propiedades físicas de los geles, es dependiente tanto del tamaño de las partículas, como de su funcionalización y concentración. Por último, se ha comprobado que debido a la optimización del cargado de ácido fólico alcanzada en la primera parte de la tesis, se puede lograr una fortificación de un yogur con el 100% de la cantidad diaria recomendada de ácido fólico con una cantidad tan pequeña de sistema que ni las propiedades físico-químicas de un yogur, ni la viabilidad bacteriana se ven comprometidas. En resumen, se puede concluir que la presente tesis ha abordado de una manera global la encapsulación de ácido fólico en matrices porosas de óxido de silicio para ser utilizados en aplicaciones nutricionales y alimentarias incluyendo estudios de optimización de cargado, estudios de liberación en función del pH, digestiones in vitro, estudios de estabilidad de las matrices utilizadas, estudios de biocompatibilidad, así como estudios de la influencia de la adición de estos sistemas inteligentes en matrices alimentarias. Los resultados obtenidos han puesto de manifiesto que los sistemas inteligentes de liberación de ácido fólico desarrollados abren la puerta a una nueva manera de fortificar los alimentos sin comprometer sus características. / [CA] La present tesi doctoral, que porta per títol "Encapsulació d'àcid fòlic en suports porosos d'òxid de silici: una aproximació nutricional i tecnològica" està centrada en el desenvolupament de nous sistemes intel·ligents de lliberació controlada d'àcid fòlic per a aplicacions nutricionals. La primera part de la tesi mostra l'encapsulació d'àcid fòlic en matrius poroses d'òxid de silici funcionalitzades amb poliamines des d'una aproximació nutricional. En esta part, s'ha avaluat la influència del mètode de carrega i del tipus de suport d'òxid de silici que s'ha emprat (MCM-41, SBA-15, UVM-7 i Hollow Silica) en l'eficàcia de l'encapsulació d'àcid fòlic. En esta primera part, també s'ha avaluat la influència de la morfologia i el sistema de porus dels diferents suports en el perfil d'alliberament de l'àcid fòlic des dels mateixos. Els estudis d'alliberament d'àcid fòlic des dels diferents suports a diferents valors de pH han demostrat que els sistemes dissenyats són capaços de modular intel¿ligentment l'alliberament d'àcid fòlic en funció del pH del medi (inhibició de l'alliberament a pH àcid -estómac-, alliberament controlat a pH neutre -intestí-). Esta capacitat fa dels sistemes desenvolupats una excel·lent alternativa a la fortificació directa per a modular amb èxit la bioaccessibilitat de l'àcid fòlic a través del tracte gastrointestinal. D'altra banda, s'ha avaluat l'estabilitat dels suports en un procés de digestió in vitro, demostrant que mentre que les partícules menudes poden ser atacades durant la digestió, la funcionalització amb molècules orgàniques que actuen com a portes moleculars prevé aquest atac. Per últim, els estudis de viabilitat cel·llular duts a terme en quatre tipus de línies cel·lulars demostren que ni els soports, ni els productes de degradació dels mateixos durant el procés de digestió in vitro promouen cap tipus de toxicitat inespecífica. En la segona part, s'ha avaluat la influència de l'addició de diferents sopors d'òxid de silici a dos matrius alimentàries, gels de gelatina i iogurts. Esta aproximació tecnològica ha permés conéixer que la capacitat d'aquests sistemes intel·ligents per alliberar controladament àcid fòlic durant un procés de digestió in vitro es manté fins i tot després de ser incorporats en iogurts batuts. D'altra banda, s'ha comprovat que l'efecte de les matrius sobre les propietats físiques dels gels, és dependent tant de la grandària de les partícules, com de la seua funcionalització i concentració. Per últim, s'ha comprovat que a causa de l'optimització del carregat d'acid fòlic alcançada en la primera part de la tesi, es pot aconseguir una fortificació d'un iogurt amb el 100% de la quantitat diària recomanada d'àcid fòlic amb una quantitat tan baixa del sistema que ni les propietats físico-químiques d'un iogurt, ni la viabilitat bacteriana se'n veuen compromeses. En resum, es pot concluir que en la present tesi s'ha abordat d'una manera global l'encapsulació d'àcid fòlic en matrius poroses d'òxid de silici per a ser utilitzades en aplicacions nutricionals i alimentàries, que inclouen estudis d'optimització de carregat, estudis d'alliberament en funció del pH, digestions in vitro, estudis d'estabilitat de les matrius utilitzades, estudis de biocompatibilitat, així com estudis de la influència de l'addició d'aquests sistemes en matrius alimentàries. Els resultats obtesos han posat de manifest de forma positiva que els sistemes intel·ligents d'àcid fòlic que s'han desenvolupat obrin una porta a una nova manera de fortificar els aliments sense comprometre les seues caracterísitiques. / Pérez Esteve, E. (2015). ENCAPSULATION OF FOLIC ACID IN MESOPOROUS SILICA SUPPORTS: A NUTRITIONAL AND TECHNOLOGICAL APPROACH [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58613 / Premios Extraordinarios de tesis doctorales / Compendio

Land application of biosolids has been demonstrated to improve nutrient availability (mainly N and P) and improve organic matter in soils, but the effects of biosolids on C sequestration and N cycling in the Mid-Atlantic region is not well understood. The objectives were: 1) to investigate soil C sequestration at sites with a long-term history of biosolids either in repeated application or single large application; 2) to characterize and compare soil C chemistry using advanced 13C nuclear magnetic resonance (NMR) and C (1s) near edge x-ray absorption fine structure (NEXAFS) spectroscopic techniques; and 3) to compare biosolids types and tillage practices on short-term N availability in the Coastal Plain soils. Biosolids led to C accumulation in the soil surface (< 15 cm) after long-time application in both Piedmont and Coastal Plain soils. The C saturation phenomenon occurred in Coastal Plain soils, thus additional soil C accumulation was not achieved by increasing C inputs from biosolids to the Coastal Plain. Soil organic C from profiles in the field sites was not different at depths below the plow layer (15-60 cm). The quantitative NMR analyses concluded that O-alkyl C was the dominant form in the particulate organic matter (POM), followed by aromatic C, alkyl C, COO/N-C=O, aromatic C-O, OCH3 / NCH and ketones and aldehydes. The aliphatic C and aromatic C were enriched but the O-alkyl C was decreased in the biosolids-amended soils. The changes indicated that the biosolids-derived soil C was more decomposed and, thus, more stable than the control. The NEXAFS spectra showed that O-alkyl C was the dominant form in the POM extracted from biosolids-amended soils, followed by aromatic C, alkyl C, carboxylic C and phenolic C groups. These results were similar to those from NMR analysis. The regression and correlation analyses of C functional groups in the POM between NEXAFS and NMR indicated that both techniques had good sensitivity for the characterization of C from biosolids-amended soils. To evaluate short-term biosolids N availability, a three-year field study to investigate the effects of lime-stabilized (LS) and anaerobically digested (AD) biosolids on N availability in a corn-soybean rotation under conventional tillage and no-tillage practices was set up in 2009-2011. Results showed that both LS and AD biosolids increased spring soil nitrate N, plant tissue N at silking, post-season corn stalk nitrate N, grain yield, and soil total N by the end of the growing season. The same factors used to calculate plant available N for incorporated biosolids can be used on biosolids applied to no-till systems in coarse-textured soils. All these results indicated that the application of biosolids affects the long-term quantification and qualification of soil organic C and also improve short-term N availability in the Mid-Atlantic region. / Ph. D.