Triple fortification of salt with vitamin A, iron, and iodine has been investigated in the past to reduce micronutrient deficiencies in the developing world. The objective is to develop integrated nutrient delivery technology by microencapsulating a self-emulsifying drug delivery system (SEDDS) made of surfactants and a bioactive compound, retinyl palmitate. The SEDDS is used to enhance absorption of the vitamin A through food systems and to achieve targeted release of the active ingredient. Encapsulating vitamin A was difficult when using the spray dryer and the enteric coating, Aquacoat®. Losses of the micronutrient after a three month storage period ranged from 50-99% at both 25°C/20% RH and 45°C/60% RH. The result of a matrix encapsulation and poor coating formation contributed to the high losses. Further investigation of coating systems with the aim of stabilizing all three samples for a six month storage period such as using other encapsulating methods is recommended.

Triple fortification of salt with vitamin A, iron, and iodine has been investigated in the past to reduce micronutrient deficiencies in the developing world. The objective is to develop integrated nutrient delivery technology by microencapsulating a self-emulsifying drug delivery system (SEDDS) made of surfactants and a bioactive compound, retinyl palmitate. The SEDDS is used to enhance absorption of the vitamin A through food systems and to achieve targeted release of the active ingredient. Encapsulating vitamin A was difficult when using the spray dryer and the enteric coating, Aquacoat®. Losses of the micronutrient after a three month storage period ranged from 50-99% at both 25°C/20% RH and 45°C/60% RH. The result of a matrix encapsulation and poor coating formation contributed to the high losses. Further investigation of coating systems with the aim of stabilizing all three samples for a six month storage period such as using other encapsulating methods is recommended.

Serine alkaline protease (SAP, EC 3.4.21.62) produced by Bacillus species, that are the microbioreactors within the bioreactors, is one of the major industrial enzymes. In this study, after production by Recombinant Bacillus subtilis (BGSC-1A751), carrying pHV1431::subc gene in the complex media and separation of solids, SAP was dried by using a spray drier. Experiments were performed to investigate the stabilization of SAP during spray drying and subsequent storage. Initially, the effect of air inlet temperature of the spray drier on SAP activity was evaluated. For this purpose, SAP solutions were spray dried in the absence of any protective agents at five different air inlet temperature (700C, 900C, 1100C, 1200C, 1300C). As a result, increasing air inlet temperature lead to an increase in activity loss of SAP during drying. Thereafter, the effect of protective additives, glucose and maltodextrin (0.5%, 1%, 2% w/v), on SAP activity was investigated during spray drying. The activity loss of SAP was completely inhibited in the presence of glucose at 70, 90 and 1100C. However, the addition of maltodextrin was better than glucose for activity preservation of SAP at 1300C. Among the obtained results, 1% glucose addition was the best to preserve activity of SAP during spray drying. Then, structural change of SAP during drying was investigated. FTIR-ATR spectrum was used to evaluate the change in physical structure of the dried SAP powders in the presence of 1% glucose. From infrared images, at 900C more native-like structure for dried SAP powders was observed. In the last stage of this study storage stability of obtained SAP powders at 40C for a long period (6 months) was investigated. When considering all conditions, 0.5% maltodextrin addition was the best for stabilizing SAP powders along storage time.

MODELING AND NUMERICAL ANALYSIS OF SINGLE DROPLET DRYING DALMAZ, Nesip M.Sc., Department of Chemical Engineering Supervisor: Prof. Dr. H. &Ouml / nder &Ouml / ZBELGE Co-Supervisor: Asst. Prof. Dr. Yusuf ULUDAg August 2005, 120 pages A new single droplet drying model is developed that can be used as a part of computational modeling of a typical spray drier. It is aimed to describe the drying behavior of a single droplet both in constant and falling rate periods using receding evaporation front approach coupled with the utilization of heat and mass transfer equations. A special attention is addressed to develop two different numerical solution methods, namely the Variable Grid Network (VGN) algorithm for constant rate period and the Variable Time Step (VTS) algorithm for falling rate period, with the requirement of moving boundary analysis. For the assessment of the validity of the model, experimental weight and temperature histories of colloidal silica (SiO2), skimmed milk and sodium sulfate decahydrate (Na2SO4&amp / #8901 / 10H2O) droplets are compared with the model predictions. Further, proper choices of the numerical parameters are sought in order to have successful iteration loops. The model successfully estimated the weight and temperature histories of colloidal silica, dried at air temperatures of 101oC and 178oC, and skimmed milk, dried at air temperatures of 50oC and 90oC, droplets. However, the model failed to predict both the weight and the temperature histories of Na2SO4&amp / #8901 / 10H2O droplets dried at air temperatures of 90oC and 110oC. Using the vapor pressure expression of pure water, which neglects the non-idealities introduced by solid-liquid interactions, in model calculations is addressed to be the main reason of the model resulting poor estimations. However, the developed model gives the flexibility to use a proper vapor pressure expression without much effort for estimation of the drying history of droplets having highly soluble solids with strong solid-liquid interactions. Initial droplet diameters, which were calculated based on the estimations of the critical droplet weights, were predicted in the range of 1.5-2.0 mm, which are in good agreement with the experimental measurements. It is concluded that the study has resulted a new reliable drying model that can be used to predict the drying histories of different materials.

Master of Engineering / Spray dryers are the core components of a milk powder production plant, where the basic configuration usually features co-current flow of milk powder and air. Spray dryers have to be cleaned frequently due to powder deposit build-up on the walls. Powder deposit build-up gives rise to lower product yields and poses a potential fire risk. If the powder deposits are scorched (from being overheated) they will contaminate, and thus compromise, the quality and consumer safety of the final product, if the powder deposits fall in and mix with it. With milk powder production rates of most industrial spray dryers ranging from 4-28 tonnes of dry powder an hour, these wall deposition problems are significant. This problem is worth investigating because the outcome of reducing or eliminating wall deposition is that a spray dryer could operate for a longer period of time without having to be cleaned. Reduction in downtime due to cleaning would give rise to increased production time and possibly a reduction in the cost of manufacturing the product. The spray dryer used in this work was a modified short-form co-current Niro unit, fabricated from stainless steel. The spray dryer had an internal diameter of 0.80 m, narrowing down to 0.06 m at the base, and a height of 2 m. A two-fluid nozzle was used to spray the process fluids (water, skim milk and grape skin extract) into the drying chamber. To measure the wall deposition fluxes on the internal walls of the spray dryer, four stainless steel plates (dimensions 110 mm by 120 mm) were inserted in place of the windows that were previously used as sight glasses. A fifth plate (dimensions 110 mm by 120 mm) and a sixth plate (dimensions 110 mm by 110 mm) were also placed on the conical section of the spray dryer at different circumferential locations. Before this work, no quantitative data on the effects of spray dryer operating conditions on the wall deposition fluxes of food material were available. This work investigated the effect on the spray deposition flux of skim milk powder on the walls of the spray dryer of (i) flow patterns in the spray dryer, by changing the degree of swirl imparted to the incoming air by using three swirl vane angles of 0o, 25o and 30o, and (ii) the stickiness of the product, through first changing the temperature of the incoming air by using three inlet air temperatures of 170oC, 200oC and 230oC; and then changing the process fluid flowrate by using three flowrates of 1.4 kg hr-1, 1.6 kg hr-1 and 1.8 kg hr-1. Previous researchers have found that the extent to which water droplets spread out in the drying chamber is affected by the amount of swirl in the inlet air. This is likely to affect wall deposition fluxes because the particles will be closer to the walls if the droplets spread out widely. The results of this work have quantitatively confirmed that the spray deposition flux increases at higher swirl vane angles, where the spray deposition flux increased from 7 g m-2 hr-1 (swirl vane angle 0o) to 12.9 g m-2 hr-1 (swirl vane angle 30o). When a swirl vane angle of 0o was used, it was observed that the cross-sectional area of the spray cloud did not change very significantly with time. However, when a swirl vane angle of 25o was used, the spray cloud was observed to “flutter”, and when the swirl vane angle was increased to 30o, the spray cloud was observed to recirculate rapidly back in the direction of the nozzle. Thus, the chance of the particles being thrown further towards the walls of the chamber is likely to increase at higher swirl vane angles. This result suggests that higher wall deposition arises because more swirl is imparted to the air entering the dryer, which in turn affects the stability of the spray cloud and, therefore, the stability of the flow patterns in the spray dryer. The stickiness of the skim milk powder is related to the temperature and moisture content of the particles. In the past, the sticky-point curve has been suggested as a semi-quantitative concept in selecting operating conditions for spray drying food material containing carbohydrates, where it has been implied that there is no significant wall deposition below the sticky-point curve. This work has quantified the spray deposition in spray dryers with respect to the sticky-point curve, where the highest spray deposition flux of skim milk powder on the walls was 16 g m-2 hr-1, and the operating point corresponding to this spray deposition flux was located at and above the sticky-point curve. Hence, both particle stickiness and flow patterns affect the wall deposition of particles in a spray dryer. This work also investigated the effect of wall properties, namely a non-stick food grade material (nylon), adhesive tape and stainless steel, on the spray deposition flux of skim milk powder on the walls. The effect of electrostatics on wall deposition was studied by grounding the spray dryer and an anti-static agent was added to the skim milk to investigate if altering the properties of the feed material could reduce wall deposition. This work has quantitatively confirmed that cohesion occurs at the same rate as adhesion for skim milk powder in this spray dryer, because firstly, decreasing the adhesion tendency of the v wall by using nylon coating had no significant effect on the spray deposition flux compared with a smooth stainless steel wall and a wall covered with a double-sided adhesive tape; and secondly the powder collected on the walls was a linear function of time with and without adhesive on the plates. Furthermore, using a nylon coated wall did not eliminate wall deposition, and the wall deposition flux was found to be the same as when a stainless steel wall was used. This result further supports the finding here that spray deposition on the walls for skim milk powder is controlled by cohesion rather than adhesion. The spray dryer operating parameters that gave rise to the least spray deposition flux on the walls were a swirl vane angle of 0o, an inlet air temperature of 230oC and a process fluid flowrate of 1.4 kg hr-1. Decreasing the feed flowrate from 1.8 kg hr-1 to 1.4 kg hr-1 (decrease by 24%), with the inlet air temperature and swirl vane angle held constant, decreased the wall deposition flux by 43% from 7 g m-2 hr-1 to 4 g m-2 hr-1. Since the spray deposition flux on the walls decreased by 43% when the feed flowrate was decreased by 24%, it might be considered that the production process is in favour of a decrease in the feed flowrate to 1.4 kg hr-1 in this dryer, and consequently a decrease in the spray deposition flux on the walls per unit production output. Finally, this work investigated if the outlet moisture content from this small spray dryer used here was equilibrium limited or controlled by drying kinetics. The findings in this work confirmed the product moisture locus concept, which implies that the outlet moisture content of the skim milk particles approaches the equilibrium moisture content (in equilibrium with the outlet gas), and that the outlet moisture content of spray-dried food material containing carbohydrates is probably not limited by particle drying kinetics, even though the spray dryer is smaller (diameter 0.8 m, height 2 m) than those used in the dairy industry, typically with a diameter of 30 m and a height of 10 m.

Master of Engineering / Spray dryers are the core components of a milk powder production plant, where the basic configuration usually features co-current flow of milk powder and air. Spray dryers have to be cleaned frequently due to powder deposit build-up on the walls. Powder deposit build-up gives rise to lower product yields and poses a potential fire risk. If the powder deposits are scorched (from being overheated) they will contaminate, and thus compromise, the quality and consumer safety of the final product, if the powder deposits fall in and mix with it. With milk powder production rates of most industrial spray dryers ranging from 4-28 tonnes of dry powder an hour, these wall deposition problems are significant. This problem is worth investigating because the outcome of reducing or eliminating wall deposition is that a spray dryer could operate for a longer period of time without having to be cleaned. Reduction in downtime due to cleaning would give rise to increased production time and possibly a reduction in the cost of manufacturing the product. The spray dryer used in this work was a modified short-form co-current Niro unit, fabricated from stainless steel. The spray dryer had an internal diameter of 0.80 m, narrowing down to 0.06 m at the base, and a height of 2 m. A two-fluid nozzle was used to spray the process fluids (water, skim milk and grape skin extract) into the drying chamber. To measure the wall deposition fluxes on the internal walls of the spray dryer, four stainless steel plates (dimensions 110 mm by 120 mm) were inserted in place of the windows that were previously used as sight glasses. A fifth plate (dimensions 110 mm by 120 mm) and a sixth plate (dimensions 110 mm by 110 mm) were also placed on the conical section of the spray dryer at different circumferential locations. Before this work, no quantitative data on the effects of spray dryer operating conditions on the wall deposition fluxes of food material were available. This work investigated the effect on the spray deposition flux of skim milk powder on the walls of the spray dryer of (i) flow patterns in the spray dryer, by changing the degree of swirl imparted to the incoming air by using three swirl vane angles of 0o, 25o and 30o, and (ii) the stickiness of the product, through first changing the temperature of the incoming air by using three inlet air temperatures of 170oC, 200oC and 230oC; and then changing the process fluid flowrate by using three flowrates of 1.4 kg hr-1, 1.6 kg hr-1 and 1.8 kg hr-1. Previous researchers have found that the extent to which water droplets spread out in the drying chamber is affected by the amount of swirl in the inlet air. This is likely to affect wall deposition fluxes because the particles will be closer to the walls if the droplets spread out widely. The results of this work have quantitatively confirmed that the spray deposition flux increases at higher swirl vane angles, where the spray deposition flux increased from 7 g m-2 hr-1 (swirl vane angle 0o) to 12.9 g m-2 hr-1 (swirl vane angle 30o). When a swirl vane angle of 0o was used, it was observed that the cross-sectional area of the spray cloud did not change very significantly with time. However, when a swirl vane angle of 25o was used, the spray cloud was observed to “flutter”, and when the swirl vane angle was increased to 30o, the spray cloud was observed to recirculate rapidly back in the direction of the nozzle. Thus, the chance of the particles being thrown further towards the walls of the chamber is likely to increase at higher swirl vane angles. This result suggests that higher wall deposition arises because more swirl is imparted to the air entering the dryer, which in turn affects the stability of the spray cloud and, therefore, the stability of the flow patterns in the spray dryer. The stickiness of the skim milk powder is related to the temperature and moisture content of the particles. In the past, the sticky-point curve has been suggested as a semi-quantitative concept in selecting operating conditions for spray drying food material containing carbohydrates, where it has been implied that there is no significant wall deposition below the sticky-point curve. This work has quantified the spray deposition in spray dryers with respect to the sticky-point curve, where the highest spray deposition flux of skim milk powder on the walls was 16 g m-2 hr-1, and the operating point corresponding to this spray deposition flux was located at and above the sticky-point curve. Hence, both particle stickiness and flow patterns affect the wall deposition of particles in a spray dryer. This work also investigated the effect of wall properties, namely a non-stick food grade material (nylon), adhesive tape and stainless steel, on the spray deposition flux of skim milk powder on the walls. The effect of electrostatics on wall deposition was studied by grounding the spray dryer and an anti-static agent was added to the skim milk to investigate if altering the properties of the feed material could reduce wall deposition. This work has quantitatively confirmed that cohesion occurs at the same rate as adhesion for skim milk powder in this spray dryer, because firstly, decreasing the adhesion tendency of the v wall by using nylon coating had no significant effect on the spray deposition flux compared with a smooth stainless steel wall and a wall covered with a double-sided adhesive tape; and secondly the powder collected on the walls was a linear function of time with and without adhesive on the plates. Furthermore, using a nylon coated wall did not eliminate wall deposition, and the wall deposition flux was found to be the same as when a stainless steel wall was used. This result further supports the finding here that spray deposition on the walls for skim milk powder is controlled by cohesion rather than adhesion. The spray dryer operating parameters that gave rise to the least spray deposition flux on the walls were a swirl vane angle of 0o, an inlet air temperature of 230oC and a process fluid flowrate of 1.4 kg hr-1. Decreasing the feed flowrate from 1.8 kg hr-1 to 1.4 kg hr-1 (decrease by 24%), with the inlet air temperature and swirl vane angle held constant, decreased the wall deposition flux by 43% from 7 g m-2 hr-1 to 4 g m-2 hr-1. Since the spray deposition flux on the walls decreased by 43% when the feed flowrate was decreased by 24%, it might be considered that the production process is in favour of a decrease in the feed flowrate to 1.4 kg hr-1 in this dryer, and consequently a decrease in the spray deposition flux on the walls per unit production output. Finally, this work investigated if the outlet moisture content from this small spray dryer used here was equilibrium limited or controlled by drying kinetics. The findings in this work confirmed the product moisture locus concept, which implies that the outlet moisture content of the skim milk particles approaches the equilibrium moisture content (in equilibrium with the outlet gas), and that the outlet moisture content of spray-dried food material containing carbohydrates is probably not limited by particle drying kinetics, even though the spray dryer is smaller (diameter 0.8 m, height 2 m) than those used in the dairy industry, typically with a diameter of 30 m and a height of 10 m.

Em um processo de fabricação de revestimentos cerâmicos por via úmida há vários custos relacionados à atomização - processo no qual ocorre à pulverização e secagem da suspensão cerâmica - tais como: combustível, manutenção e perda de produção. O principal custo da manutenção está relacionado com a troca do bico desgastado, em especial o componente interno (pastilha furada) de WC-Co, que tem vida útil de cinco dias, devido ao elevado desgaste erosivo provocado pelas partículas cerâmicas. Neste trabalho foi realizado tratamento superficial, o qual consiste na aplicação de filmes finos (AlCrN, AlCrN_TiSiN e TiAlN) sobre as pastilhas furadas de WC-Co via PAPVD (deposição física de vapor assistida por plasma) para aumentar sua resistência ao desgaste. Indentações Rockwell “A” com carga de 60 kgf foram realizadas para caracterizar a adesão dos filmes nos substratos. Em seguida as pastilhas furadas de WCCo com tratamento e sem tratamento foram caracterizadas quanto à rugosidade, fases presentes por difração de raios X, microdureza, e carga de ruptura e espessura dos revestimentos. Analisou-se a microestrutura transversal e superficial das amostras tratadas e não tratadas através do microscópio eletrônico de varredura (MEV). Também foi desenvolvido um pulverizador de bancada piloto para testes, no qual pastilhas furadas revestidas e não revestidas foram testadas usando-se uma suspensão cerâmica de feldspato. A pastilha revestida que obteve menor desgaste erosivo no protótipo foi a WC-Co + AlCrN. Este recobrimento apresentou propriedades intermediárias de dureza e boa qualidade de adesão em relação aos demais tratamentos empregados. Em seguida, substratos de dois fornecedores (“A” e “B”) foram revestidos com AlCrN para serem testados em um atomizador industrial. Nesta aplicação, os melhores resultados foram obtidos para os substratos do fornecedor “A”. Observou-se que as amostras do fornecedor “A” apresentaram dureza similar em relação às amostras do fornecedor “B”, porém, somente as amostras do fornecedor “A” foram aprovadas em relação à qualidade de adesão, conforme a norma alemã VDI 3198. Foi possível estimar um aumento de 40% na vida útil da pastilha furada. / In a spray-drying process of a ceramic suspension for production of ceramic tiles there are many costs related to: fuel, maintenance and productions losses. The main cost in maintenance is related to the exchange of the worn spray nozzle, especially the nozzle stuck, an internal component made of WC-Co that has a shelf life of five days due to the high erosive wear caused by ceramics particles. In this work surface treatment to produce thin films (AlCrN, AlCrN_TiSiN e TiAlN) on the nozzle stuck, made of WCCo, via PAPVD (Plasma Assisted Physical Vapor Deposition) was carried out in order to increase its wear resistance. Rockwell “A” indentation with 60 kgf loading was used in order to characterize the adhesion of films. The films and the substrate were also characterized by x-ray diffraction, roughness, microhardness, rupture load, and coating thickness. The microstructure was analyzed by SEM. A spray pilot bench was constructed for testing the parts with or without treatment using a ceramic suspension of feldspar. The samples who achieved less erosive wear in the prototype was WCCo+ AlCrN. This coating developed higher adhesion and intermediate hardness compared to other treatments. Substrates from two suppliers ("A" and "B") were treated with AlCrN and subsequently tested in an industrial spray-dyer. In this application the best results were obtained for the substrates of supplier "A". It was observed that samples of supplier "A" showed similar hardness for the samples from "B", but adherence was significantly greater for supplier "A". It could be estimate an increasing of 40% in a shelf life of a nozzle stuck.

ALMEIDA, Francisca Diva Lima. Desidratação de suco de abacaxi probiótico por spray dryer. 2012. 70 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2012 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-06T13:15:08Z No. of bitstreams: 1 2012_dis_fdlalmeida.pdf: 903522 bytes, checksum: 11bab1e58839f6c90277a5e820ce8712 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-06T13:15:28Z (GMT) No. of bitstreams: 1 2012_dis_fdlalmeida.pdf: 903522 bytes, checksum: 11bab1e58839f6c90277a5e820ce8712 (MD5) / Made available in DSpace on 2016-06-06T13:15:28Z (GMT). No. of bitstreams: 1 2012_dis_fdlalmeida.pdf: 903522 bytes, checksum: 11bab1e58839f6c90277a5e820ce8712 (MD5) Previous issue date: 2012 / Recent researches show the potential use of fruit juices as an excellent way to carry probiotic microorganisms. Thus, the aim of the following study was to develop a new non-dairy probiotic food from of pineapple juice containing Lactobacillus casei NRRL B-442 dehydrated by spray-drying process. Firstly, the pineapple juice underwent a heat treatment (90 ° C / 1 minute) in order to inactivate the proteases present in the juice and evaluate the influence of enzyme inactivation on the microorganism survival. Subsequently, the employment of three temperatures (150, 120 and 100 ° C) on the juice dehydration was appraised, with the purpose of defining an appropriate temperature based on the microorganism survival, after the dehydration process. Other parameters were also studied, such as: the effect of addition of different materials (gelatin, gum arabic, maltodextrin), which were used as protective agents for the microorganism, as well as the concentration of each tested adjuvant. Viability of L. casei (before and after the drying process), powder yield and rehydration levels and the color of the reconstituted juice were also assessed. Based on the attained results, it can be concluded that the utilization of lower temperatures (100 ° C) and the appliance of heat treatment in the juice favored the survival of L. casei after dehydration. Excellent levels of microorganism survival after the drying process were achieved by using 10% gelatin and 5% gum arabic as protective agents, thus showing a promising possibility of formulating a new powder probiotic food without the restrictions inherent in dairy products. / Pesquisas recentes apontam a utilização de sucos de frutas como excelente meio para veicular micro-organismos probióticos. Diante disso, o objetivo desse trabalho foi desenvolver um novo alimento probiótico de origem não láctea, a partir da desidratação, por spray dryer, do suco de abacaxi contendo Lactobacillus casei NRRL B-442. Primeiramente, foi realizado um tratamento térmico no suco de abacaxi (90 ºC /1minuto) com o objetivo de inativar as proteases presentes no mesmo e avaliar a influência da inativação dessa enzima na sobrevivência do micro-organismo. Posteriormente, foi avaliado o uso de três temperaturas (150, 120 e 100 ºC) para a desidratação do suco, a fim de definir uma temperatura adequada com base na sobrevivência do micro-organismo após o processo de desidratação. Outros parâmetros também foram estudados, tais como: o efeito da adição de diferentes materiais (gelatina, goma arábica, maltodextrina), os quais foram empregados como agentes protetores do micro-organismo, bem como a concentração de cada agente utilizada. A viabilidade do L. casei antes e após a secagem, os níveis de rendimento e reidratação do pó e a cor do suco reconstituído também foram avaliados. Com base nos resultados obtidos podemos concluir que o uso de temperaturas mais baixas (100ºC) e a aplicação de tratamento térmico no suco favoreceram a sobrevivência do L. casei após desidratação do suco. O emprego de 10% de gelatina e 5% de goma arábica, como agente de proteção, garantiu excelentes níveis de sobrevivência do micro-organismo após a secagem mostrando, dessa forma, que é possível formular um novo alimento probiótico em pó sem as limitações dos produtos lácteos.

O interesse pela extração dos compostos bioativos, a partir de fontes naturais, para o emprego na produção de alimentos funcionais tem aumentado, devido, principalmente, à crescente demanda por parte dos consumidores, por produtos mais saudáveis e que possam trazer benefícios à saúde. Dentre as fontes naturais de compostos bioativos, destaca-se o hibisco (Hibiscus sabdariffa L.), que é rico em antocianinas, flavonoides, ácidos fenólicos, carotenoides, dentre outros. Entretanto, quando os compostos bioativos são separados de suas matrizes, estes se tornam altamente instáveis frente a diversos fatores ambientais, necessitando serem protegidos. O recobrimento por microencapsulamento é uma alternativa para retardar a degradação desses compostos. Este estudo teve como objetivo a extração, identificação, quantificação e microencapsulamento por atomização e liofilização dos compostos bioativos dos cálices do hibisco. Primeiramente, foi realizada a extração exaustiva total dos carotenoides e compostos fenólicos por meio de solventes orgânicos, para a identificação e quantificação desses compostos. Também foi estudada a extração de antocianinas e demais compostos fenólicos por meio de solvente aquoso acidificado (ácido cítrico 2 %, p/v). A partir do melhor tratamento de extração, o extrato obtido foi microencapsulado mediante atomização e liofilização, empregando goma arábica (GA), goma guar parcialmente hidrolisada (GGPH) e polidextrose (PD) como agentes encapsulantes, na concentração de 10%. Os carotenoides e compostos fenólicos foram identificados e quantificados por HPLC-DAD-MS/MS (cromatografia líquida de alta eficiência com detecção por arranjo de diodos e espectrometria de massa). Vinte e um carotenoides foram encontrados, dos quais, quinze foram identificados. O total de carotenoides nos cálices de hibisco foi de 641,38 ± 23,61 μg/100 g massa fresca, sendo a all-trans-luteína e o all-trans--caroteno os compostos majoritários, representando 49 e 23%, respectivamente. Para os compostos fenólicos, foram encontrados vinte compostos, dos quais, catorze foram identificados. As antocianinas foram os compostos majoritários nos cálices de hibisco, sendo que a delfinidina 3-sambubiosídeo e cianidina 3-sambubiosídeo representaram 41 e 13% do total de compostos fenólicos, respectivamente. Dentre os ácidos fenólicos, os componentes majoritários foram o ácido 3-cafeoilquínico e ácido 5-cafeoilquínico, representando 15 e 13% do total de compostos fenólicos, respectivamente. Para a extração aquosa acidificada, foi utilizado um planejamento experimental fatorial fracionado (24-1), com quatro fatores: concentração de enzima, temperatura, velocidade de agitação e tempo de extração. A partir da ANOVA, os efeitos principais e de interação foram avaliados, tendo como respostas Chroma, antocianinas monoméricas totais (TMA), capacidade redutora, ABTS e compostos fenólicos. A partir dos resultados, o melhor tratamento foi: 55 °C, 50 μL de enzima/1000 g extrato, 400 rpm e 4 horas de extração, obtendo-se nessa condição de extração 3,82 mg/g extrato em base seca para TMA e 17,59 mg/g de extrato em base seca para compostos fenólicos totais, que resultou em capacidade antioxidante de 7,72 μmol Eq. Trolox/g de extrato em base seca, avaliado por ABTS e de 3,96 mg GAE/g de de extrato em base seca, avaliado pela capacidade redutora. Este extrato foi empregado no estudo de encapsulamento, por atomização (140 ºC) e liofilização (-68 ºC por 24 horas), utilizando GA, GGPH e PD como encapsulantes. Observou-se que o melhor tratamento foi por liofilização empregando GA como encapsulante, resultando em 2,83 mg/g amostra em base seca para TMA, capacidade antioxidante de 2,98 mg GAE/g amostra em base seca e 5.67 μmol Eq. Trolox/g amostra em base seca, avaliados por capacidade redutora e ABTS, respectivamente. Entretanto, quando foram avaliadas as propriedades físicas e morfológicas dos pós, as amostras elaboradas por atomização e usando GA e GGPH apresentaram os melhores desempenhos, onde os valores de solubilidade, higroscopicidade e umidade foram de 95,8 e 95,2%, 31,3 e 28,9%, 1,9 e 2,4%, respectivamente. Para a temperatura de transição vítrea (Tg), os tratamentos que utilizaram GA e GGPH nos dois métodos de encapsulamento, tiveram os maiores valores de Tg, variando de 10,9 a 17,4 ºC. Já para os tratamentos que utilizaram a PD como material de parede, os valores foram de (0,7 °C), tanto na atomização como na liofilização. Na microscopia também foi observado um melhor desempenho nas micropartículas atomizadas usando GA e GGPH, as quais mostraram partículas mais esféricas e sem tendência de atração e aderência entre si. Em relação ao diâmetro médio de partícula (D[4, 3]), os tratamentos liofilizados tiveram partículas maiores que os atomizados, variando de 101,7 a 143,1 μm para os liofilizados, e de 5,4 a 7,3 μm para os atomizados. Quanto ao span, o qual avalia distribuição de tamanho de partícula, variou de 1,90 a 2,00 para as amostras atomizadas e de 3,06 a 3,19 para as amostras liofilizadas, indicando que houve uma boa uniformidade na distribuição de tamanho de partícula. Conclui-se que o hibisco é uma matriz com ampla composição de compostos bioativos e tem potencial para aplicação em alimentos. / The interest in the extraction of bioactive compounds from natural sources, for use in the production of functional foods has increased, mainly due to the growing demand by consumers for healthier products and can bring health benefits. Among the natural sources of bioactive compounds, stands out the hibiscus (Hibiscus sabdariffa L.), which is rich in anthocyanins, flavonoids, phenolic acids, carotenoids, among others. However, when the bioactive compounds are separated from their matrix, they become highly unstable against various environmental factors and need to be protected. The coating by microencapsulation is an alternative to slow the degradation of these compounds. This study aimed at the extraction, identification, quantification and microencapsulation by spray drying and freeze drying of bioactive compounds of hibiscus calyces. Firstly, a thorough exhaustive extraction of carotenoids and phenolic compounds by organic solvents was performed for identification and quantification of these compounds. The extraction of anthocyanins was also studied along with other phenolic compounds by an aqueous solvent acidified (2% citric acid, w/v). From the best treatment for extraction, the extract obtained was microencapsulated by spray drying and freeze drying using Arabic gum (GA), partially hydrolyzed guar gum (PHGG) and polydextrose (PD) as encapsulating agents in a concentration of 10%. Carotenoids and phenolic compounds were identified and quantified by HPLC-DAD-MS/MS (high-performance liquid chromatography with diode array detection and mass spectrometry). Twenty-one carotenoids were found, of which fifteen were identified. The total carotenoids in hibiscus calyces was 641.38 ± 23.61 mg/100 g fresh weight, with the all-trans-lutein and all-trans-β-carotene the major compounds, representing 49 and 23%, respectively. Regarding the phenolic compounds it was found twenty of those, of which fourteen have been identified. Anthocyanins were the main components in the hibiscus calyces, and delphinidin and cyanidin 3-sambubioside 3-sambubioside represented 41 and 13% of total phenolic compounds, respectively. Among the phenolic acids, the major components were the 3-caffeoylquinic acid and 5-caffeoylquinic acid, representing 15 and 13% of total phenolic compounds, respectively. For acidified aqueous extraction, we used a fractional factorial design (24-1) with four factors: enzyme concentration, temperature, stirring speed and extraction time. From the ANOVA, the main and interaction effects were assessed as answers: Chroma, total anthocyanins monomeric (TMA), reducing capacity, ABTS and phenolic compounds. From the results, the best treatment was with 55 °C, 50 μL of enzyme/1000 g extract, 400 rpm and 4 hours of extraction, it was obtained in this extraction condition 3.82 mg/g extract on a dry basis for TMA and 17.59 mg/g extract on a dry basis for phenolic compounds, which resulted in antioxidant capacity of 7.72 μmol Eq. Trolox/g extract on a dry basis, evaluated by ABTS and 3.96 mg GAE/g extract on a dry basis, assessed by reducing capacity. This extract was used for the encapsulation study, by spray drying (140 °C) and freeze drying (-68 ° C for 24 hours) using GA, PHGG, and PD as encapsulants. It was observed that the best treatment is by freeze drying using GA as encapsulant, resulting in 2.83 mg/g sample on dry basis for TMA, antioxidant capacity of 2.98 mg GAE/g sample on dry basis and 5.67 μmol Eq. Trolox/g sample on dry basis, evaluated by reducing capacity and ABTS, respectively. However, when we evaluated the physical and morphological properties of powders, samples prepared by spray drying and using GA and PHGG showed the best performance, and the values for solubility, hygroscopicity and moisture were 95.8 and 95.2%, 31.3 and 28.9%, 1.9 and 2.4%, respectively. For the glass transition temperature (Tg), treatments with GA and PHGG on both encapsulation methods had high Tg values ranging from 10.9 to 17.4 °C. As for treatments of PD as wall material, the values were (0.7 °C), both the spray drying as in freeze drying. In microscopy was also observed improved performance in spray-dried microparticles using GA and PHGG, which showed more spherical particles and with no tendency to attract and adhere to each other. Regarding the average particle diameter (D [4, 3]), the freeze-dried treatments had higher spray-dried particles ranging from 101.7 to 143.1 μm for freeze-dried, and 5.4 to 7.3 μm for spray-dried. As the span, which assesses particle size distribution ranged from 1.90 to 2.00 for spray-dried samples and 3.06 to 3.19 for the freeze-dried samples, indicating that there was a good uniformity in the size in the distribution of the size of the particle. It follows that hibiscus is a matrix with broad composition and bioactive compounds have potential for application in foods.

Objetivos: O objetivo do trabalho foi preparar suspensões de nanocápsulas poliméricas contendo melatonina e secá-las utilizando adjuvantes hidrossolúveis, bem como realizar a caracterização físico-química e avaliação da permeação cutânea das formulações obtidas. Métodos: As suspensões de nanocápsulas poliméricas contendo melatonina foram preparadas pelo método de deposição interfacial do polímero pré-formado. As suspensões de nanocápsulas foram caracterizadas em termos de determinação do diâmetro de partículas, índice de polidispersão, pH e potencial zeta. Considerando-se que as suspensões poliméricas podem ser formulações instáveis, sujeitas ao crescimento microbiano e degradação química dos componentes, empregou-se a técnica de secagem por aspersão, como uma alternativa para aumentar a estabilidade desse tipo de sistema mediante a sua conversão em produtos pulverulentos. Para que os pós resultantes fossem ressuspendíveis em água optou-se pela utilização de adjuvantes de secagem hidrossolúveis, como a lactose e a maltodextrina, na proporção de 10 % (m/v). As formulações obtidas foram incorporadas em hidrogéis e caracterizadas quanto as suas propriedades organolépticas, doseamento, morfologia e potencial zeta. Além disso, as formulações foram avaliadas através de diálise da melatonina em função do tempo em meio aquoso contendo 5 % de Tween 80® e quanto à permeação in vitro do fármaco através da pele de suíno em função do tempo. Resultados e conclusões: As suspensões e pós de nanocápsulas foram obtidos com sucesso. As formulações apresentaram um perfil de liberação descrito por uma equação biexponencial, exceto a solução de melatonina livre em 10 % de etanol que correspondeu ao modelo monoexponencial. Nos testes de permeação, os pós de nanocápsulas apresentaram permeação significativamente menor da melatonina na pele (p < 0,05) em comparação com o hidrogel contendo fármaco livre, porém não foram significativamente distintos entre si. Em geral, as nanocápsulas em pó secas utilizando lactose, forneceram um pó com melhor redispersibilidade e menor tamanho médio de partícula, adequado para a aplicação tópica. / Aims: The objective was to prepare polymeric melatonin-loaded nanocapsule suspensions and dry them by using hydrophilic excipients and spray-drying technique. Perform physical-chemical characterization and evaluation of skin permeation of the formulations obtained. Methods: The polymeric melatonin-loaded nanocapsule suspensions were prepared by interfacial deposition of preformed polymer. The nanocapsule suspensions were characterized in terms of size, polydispersity index and zeta potential. Considering the instability of suspensions which are vulnerable to microorganism growing and the chemical degradation of components, we propose to convert them in powders by spray-drying for increasing the stability. The presence of water soluble excipients, lactose or maltodextrin, 10 % (w/v), as drying adjuvants furnished redispersible dried powders. These powders were incorporated in gels and characterized in terms of organoleptic parameters, melatonin content, morphology and zeta potencials. Furthermore, dialysis in cellulose membrane and permeation studies in pig’s skin were carried out. Results and Discussion: The suspensions and powders of nanocapsules were successful obtained. The in vitro release profiles of nanostructured formulations were better described by the biexponential model while the ethanol 10 % solution containing free melatonin fits better the monoexponential equation. In permeation tests, the powders (NCL and NCM) demonstrated significant reductions of melatonin permeation (p < 0,05) compared to melatonin free gel, but no significant differences among the different powders. In general, the spray dried nanocapsules using lactose provide a powder with better redispersibility and smaller particle size, suitable for topical application.