A jabuticaba é uma fruta originalmente brasileira e que começa a ser explorada comercialmente para produção de polpa congelada, geleia, licor, dentre outros produtos. O processamento da jabuticaba gera uma grande quantidade de resíduos, oriundos da casca e da semente, que normalmente são descartados em aterros, contribuindo para poluição ambiental. Todavia, esses resíduos são ótimas fontes de ingredientes funcionais, tais como antocianinas (pigmentos roxos) e elagitaninos, ambos potentes antioxidantes. Assim, o objetivo deste estudo foi extrair o pigmento do resíduo do despolpamento da jabuticaba e caracteriza-lo; estudar o processo de secagem por atomização do pigmento;caracterizar os pós obtidos, bem como sua propriedade antioxidante e estabilidade durante o armazenamento. Para tanto, a jabuticaba foidespolpada, e do resíduo (cascas e sementes) foi obtido um extrato aquoso, o qual foi caracterizado quanto ao teor de sólidos solúveis, pH, umidade, cinzas, proteínas, lipídeos, fibras, açúcares e acidez, e, em seguida, foi desidratado em spray-dryer com os agentes carreadores maltodextrina DE10 e goma arábica. Os pós obtidos foram caracterizados quanto à umidade, higroscopicidade, cor instrumental, morfologia e tamanho das partículas, teor de antocianinas, estabilidade e propriedade antioxidante pelos métodos ORAC e DPPH, estabilidade durante estocagem e isotermas de sorção. O extrato aquoso obtido apresentou 10% de sólidos solúveis totais, pH 3,54, acidez de 0,71 g ácido cítrico/100g amostra e teor de antocianinas de 79,3 mg de antocianinas/100g de amostra. Os pós obtidos com maltodextrina em condições otimizadas apresentaram retenção média de antocianinas de 77%, umidade média de 4,0%, higroscopicidade média de 34,9 g de água absorvida/100 g de pó, rendimento médio do processo de 32,1% e em média 11,5 mg/g pó de antocianinas totais. Os valores médios para a atividade antioxidante variaram de 826,9 a 266,0 µmoles equivalentes de Trolox/g pelos métodos ORAC e DPPH, respectivamente. Já para os pós obtidos com goma arábica em condições otimizadas a retenção média de antocianinas foi de 86%, umidade média de 3,9%, higroscopicidade média de 56,1 g água absorvida/100g pó, rendimento médio do processo de 35,7% e em média 14,8 mg/g pó de antocianinas totais. Os valores médios para a atividade antioxidante variaram de 227,2 a 1152,7 µmoles equivalentes de Trolox/g de pó pelos métodos DPPH e ORAC, respectivamente. Os pós obtidos apresentaram valores altos para antocianinas, fenólicos totais e atividade antioxidante, mostrando o grande potencial do resíduo do despolpamento da jabuticaba para produção de um pigmento funcional. A presença do carreador foi efetiva para manter a estabilidade do pigmento durante a estocagem e quanto maior a sua concentração, maior a estabilidade do pigmento. / The jabuticaba is originally a Brazilian fruit and begins to be exploited commercially for the production of frozen pulp, jelly, liquor, among oth er products. The processing of jabuticaba generates a lot of waste, from the peel and seeds, which are usually discarded in landfills, contributing to environmental pollution. However, these residues are good sources of functional ingredients, such as anthocyanins (purple pigments) and elagitannins, both potent antioxidants. The objective of this study was to extract the pigment from the pulping of jabuticaba\'s waste and characterized it, to study the process of spray drying the pigment; characterize the po wders, as well as its antioxidant properties and storage stability. To this aim, jabuticaba was pulped, and the residue (peel and seeds) was obtained from an aqueous extract, which was characterized as the soluble solids, pH, moisture, ash, protein, lipid, fiber, sugars and acidity, and then was dried in a spray-dryer with agents carriers of 10 maltodextrin and gum arabic. The powders were characterized for moisture, hygroscopicity, instrumental color, morphology and particle size, anthocyanins, stability and antioxidant properties by ORAC and DPPH methods and stability during storage. The aqueous extract obtained showed 10% of total soluble solids, pH 3.54, acidity 0.71 g citric acid/100g sample and anthocyanin content of 79.3 mg anthocyanin/100g sample. The powders obtained under optimized conditions with maltodextrin showed retention of 77% anthocyanins, 4.0% of humidity, hygroscopicity of 34.9 g water absorbed/100g powder, yield of the process 32.1% and on average 11.5 mg/g of anthocyanins. The mean values for the antioxidant activity ranged from 826.9 µM Trolox equivalents/g jabuticaba\'s powder to 266.0 µM Trolox equivalents/g jabuticaba\'s powder for ORAC and DPPH methods, respectively. The gum arabic powders obtained under optimized conditions showed average retention of 86% anthocyanins, 3.9% average humidity, hygroscopicity average of 56.1 g water absorbed/100g powder, average yield of 35.7% of the process and an average of 14.8 mg/g powder anthocyanins. The mean values for the antioxidant activity ranged from 1152.7 µM Trolox equivalents/g jabuticaba\'s powder to 227.2 µM Trolox equivalents/g jabuticaba\'s powder for ORAC and DPPH methods, respectively. The powders obtained showed high concentration of anthocyanins, phenolic compounds and antioxidant activity, showing the great potential of the residue of jabuticaba\'s waste for production of a functional pigment. The presence of the carrier was effective for maintaining stability of the pigment during storage and the higher the concentration, the greater the stability of the pigment

A mucopolissacaridose tipo I (MPS I) é uma doença autossômica recessiva causada pela deficiência da enzima α-L-iduronidade (IDUA). Essa deficiência resulta no acúmulo de glicosaminoglicanos levando a diversas manifestações clínicas. A microencapsulação de células recombinantes que superexpressam IDUA tem sido considerada uma estratégia promissora para o tratamento de MPS I. Neste contexto, o presente estudo teve por objetivo a otimização da encapsulação de células BHK (Baby Hamster Kidney) superexpressando IDUA em microcápsulas de alginato revestidas com poli-L-lisina (PLL) utilizando-se um extrusor eletrostático. Em uma primeira etapa, um estudo de otimização das microcápsulas de alginato (MC-A) foi realizado por meio de um desenho experimental do tipo Box-Behnken (software Mini-Tab®) que permitiu avaliar simultaneamente a influência da voltagem (kV), fluxo alginato/células (mL/h) e concentração de alginato (%) sobre o tamanho das microcápsulas e a atividade de IDUA. Após, as microcápsulas foram revestidas sequencialmente com PLL e alginato (MC-APA) com o objetivo de aumentar a sua estabilidade. Nas condições experimentais empregadas, MC-A e MC-APA apresentaram-se monodispersas (span < 1,22) com um diâmetro médio inferior a 350 μm, determinado por difração a laser. O revestimento alterou a morfologia das microcápsulas (microscopia eletrônica de varredura) e a sua resistência mecânica (analisador de textura), sendo observado um aumento de cerca de 6 vezes na força necessária para compressão das mesmas. O revestimento final pelo alginato (MC-APA) parece ter sido parcial de acordo com as análises de infravermelho por transformada de Fourier com refletância atenuada. Em uma última etapa, a atividade enzimática foi avaliada em modelo murino MPS I após implante subcutâneo de MC-APA. Foi observado um aumento significativo da atividade de IDUA na pele, após 30 dias de tratamento. Nas análises histológicas foi observado um infiltrado inflamatório no local da aplicação que não impediu a liberação da enzima nas condições avaliadas. No seu conjunto, esse estudo demonstra a potencialidade das MC-APA para a liberação local de IDUA. / Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disorder caused by the deficiency of α-L-iduronidase (IDUA). This deficiency results in the accumulation of glycosaminoglycans leading to various clinical manifestations. The microencapsulation of recombinant cells overexpressing IDUA has been considered as a promising strategy for the treatment of MPS I. In this context, the present study aimed to optimize the encapsulation of BHK cells overexpressing IDUA in poly-L-lysine (PLL) coated alginate microcapsules using an electrostatic extruder. In a first step, a Box-Behnken experimental design (Mini-Tab® software) was carried out for the optimization of the alginate microcapsules (MC-A), which allowed to evaluate simultaneously the influence of voltage (kV), alginate/cell flow (mL/h) and alginate concentration (%) on the size of the microcapsules and IDUA activity. Thereafter, the microcapsules were sequentially coated with PLL and alginate (MC-APA) in order to increase their stability. In the experimental conditions used, MC-A and MC-APA were monodisperse (span <1.22) with an average diameter of less than 350 μm, determined by laser diffraction. The coating modified microcapsules morphology (scanning electron microscopy) and their mechanical resistance (texture analyzer), being observed a six-fold increase in the required force for their compression. The final alginate coating (MC-APA) appears to have only partially coated the microcapsules, according to the attenuated total reflectance Fourier transform infrared spectroscopy analyses. In a final step, the enzymatic activity was evaluated in a MPS I murine model after subcutaneous implantation of MC-APA. A significant increase in IDUA activity was observed in the skin at 30 days after treatment. Histological analszes revealed an inflammatory infiltrate at the application site, which did not prevent the release of the enzyme under the evaluated conditions. Overall, this study demonstrates the potentiality of MC-APA for the local release of IDUA.

Este trabalho teve como objetivo a utilização da tecnologia que emprega CO2 em estado supercrítico para estudar a formação de micropartículas de óleos essenciais encapsulados em polissacarídeos. O referido tema tem caráter inovador e inédito, já que a tecnologia supercrítica tem sido utilizada na formação e impregnação de partículas, principalmente de solutos sólidos, mas não tem sido aplicada na encapsulação de óleos essenciais. Os processos estudados, RESS (Rápida Expansão de uma Solução Supercrítica) ou o PGSS (Partículas de Soluções ou Suspensões em Gás Saturado) envolvem baixas temperaturas, possibilitando a não degradação de compostos voláteis e termossensíveis, tornando-os mais estáveis. Foram utilizados nesta pesquisa, polímeros que são, normalmente, utilizados no processo convencional de \"aroma em pó\". Mesmo sendo insolúveis ou parcialmente solúveis em CO2 supercrítico houve o intuito de aproveitar estudos comprovados de estabilidade de óleos essenciais encapsulados nestes materiais e ainda manter o custo do produto já que polissacarídeos tem, relativamente, baixo valor comercial, quando comparado aos polímeros que são empregados nos estudos que usam estes processos. Ensaios preliminares foram realizados com diferentes polímeros: Amido modificado, dextrina, maltodextrina e Purity Gum Ultra&reg;, (gentilmente cedidos pela Corn Products, atual Ingredion Incorporated, Mogi Guaçu, SP, BR) no intuito de selecionar o material de parede mais apropriado para a microencapsulação do óleo essencial, representado pelo limoneno. Os resultados preliminares comprovaram que houve impregnação e possível microencapsulação do limoneno, observados e constatados através de análises de microscopia (óptica, eletrônica e de fluorescência confocal a laser) especialmente para Purity Gum Ultra&reg;, a qual apresentou comportamento desejável como estabilidade da dispersão preliminar e morfologia, em comparação com os outros polissacarídeos testados (dextrina, amido modificado e maltodextrina). Os ensaios subsequentes (dimensionamento das partículas, microscopia eletrônica de varredura, microscopia confocal na presença de fluoresceína, estabilidade térmica e quantificação do teor de limoneno microencapsulado) determinaram definitivamente a eficiência da Purity Gum Ultra&reg; como polímero mais apropriado como agente encapsulante, e com isso foi demonstrada a eficiência da técnica proposta para esta finalidade. Ainda, a técnica de microencapsulação empregada (PGSS) apresentou valores significativos na retenção do limoneno com até 86% quando a suspensão foi preparada utilizando etanol (EtOH) e lecitina de soja como surfactante, sendo um relevante indicativo de que o processo de microencapsulação via PGSS proporcionou eficiente retenção do limoneno, além de apresentar outras vantagens sobre os processos de microencapsulação convencionais utilizados na indústria de alimentos. O processo de microencapsulação que utiliza CO2 supercrítico é considerado como \"tecnologia limpa\", aliado a este solvente ser considerado abundante, barato e ambientalmente seguro. Neste estudo constatou-se que, além do emprego de baixa temperatura no processo (50 - 60º C), não houve necessidade do emprego de água na suspensão. / This study aimed to use the technology that employs CO2 in supercritical state to study the formation of microparticles encapsulated essential oils in polysaccharides. The supercritical technology has been used in impregnating particles, mostly of solid solutes, but has not been applied to the encapsulation of essential oils. The studied processes RESS (Rapid Expansion of a Supercritical Solution) or PGSS (Particles Solutions or Suspensions in Saturated Gas) involving low temperatures, not allowing degradation of volatile and polymers that are normally used in the conventional process of \"aroma powder\" were used in this study. Even though it is insoluble or partially soluble in supercritical CO2 proven in order to take advantage of the stability studies of encapsulated essential oils in these materials and still keep the cost of the product as polysaccharides have relatively low value when compared to the polymers that are employed in studies using these processes. Preliminary tests were performed with different polymers : modified starch, dextrin, maltodextrin and Purity Gum Ultra &reg;, ( kindly provided by Corn Products, Current Ingredion Incorporated, Mogi, SP, BR ) in order to select the most appropriate material for wall microencapsulation of essential oil, represented by limonene. Preliminary results showed that there was possible impregnation and microencapsulation of limonene, observed and recorded through analysis of microscopy (optical, electron and confocal) especially for Purity Gum Ultra &reg;, which showed desirable behavior such as dispersion and stability of primary morphology compared to other polysaccharides tested (dextrin, modified starch and maltodextrin). Subsequent tests (particle sizing, scanning electron microscopy, confocal microscopy in the presence of fluorescein, thermic stability and quantification of the limonene content microencapsulated definitely determined the efficiency of Purity Gum Ultra &reg; as the most appropriate polymer as agent encapsulating and it has been demonstrated the efficiency of the proposed technique for this purpose. The technique employed for microencapsulation (PGSS) showed significant amounts of limonene retention of up to 86% when the suspension was prepared using ethanol (EtOH) and soy lecithin as surfactant. Being indicative of a material that microencapsulation by PGSS provided efficient retention of limonene, besides other advantages over conventional microencapsulation processes used in the food industry. The microencapsulation process that uses CO2 supercritical is considered \"clean technology \" due to the low toxicity of CO2 besides this solvent is considered abundant, inexpensive and environmentally safe. In this study it was found that, in addition to using low temperature process ( 50 - 60º C ), there was no need for the use of water in suspension.

Dans le domaine pharmaceutique, la voie orale demeure la voie d’administration de prédilection, car plus simple et mieux acceptée par les patients. Cependant, ce mode d’administration pose problème pour de nombreux principes actifs (PA) présentant une faible solubilité, une faible perméabilité et/ou une instabilité dans l’environnement gastro-intestinal. Leur micro-encapsulation dans des matrices polymériques peut permettre d’y répondre, notamment si les microparticules générées résistent aux environnements rencontrés lors du tractus gastro-intestinal et jouent alors un rôle protecteur, tant pour le principe actif que pour les muqueuses rencontrées. La recherche de nouveaux excipients, issus des agro-ressources tels que les polymères naturels, est en plein essor. Les protéines végétales, grâce à leurs propriétés fonctionnelles telles qu’une bonne solubilité, une viscosité relativement basse, et des propriétés émulsifiantes et filmogènes, représentent des candidats privilégiés. De plus, la grande diversité de leurs groupements fonctionnels permet d’envisager des modifications chimiques ou enzymatiques variées. L’objectif de ce travail était d’étudier l’intérêt de la protéine de soja en tant que matériau enrobant de principes actifs pharmaceutiques destinés à la voie orale, et plus particulièrement en tant que candidat pour l’élaboration de formes gastro-résistantes. Un isolat protéique de soja (SPI) été utilisé comme matière enrobante et l’atomisation comme procédé. L’ibuprofène, anti-inflammatoire non stéroïdien, a été choisi comme molécule modèle du fait de sa faible solubilité nécessitant une amélioration de sa biodisponibilité, et de ses effets indésirables gastriques nécessitant une mise en forme entérique. Deux modifications chimiques des protéines (l’acylation et la succinylation) ont été étudiées dans le but de modifier la solubilité de la protéine de soja. Ces modifications ont été effectuées dans le respect des principes de la Chimie Verte, notamment en absence de solvant organique. Les microcapsules obtenues par atomisation ont été caractérisées en termes de taux et efficacité d'encapsulation, morphologie et distribution de tailles des particules, état physique du PA encapsulé et capacité de libération en milieu gastrique et intestinal simulé. Les résultats obtenus ont permis de valider l’intérêt des modifications chimiques de la protéine de soja pour moduler les cinétiques de libération d’actif. Les modifications chimiques sont apparues particulièrement adaptées pour l’encapsulation de principes actifs hydrophobes, et ont permis de l’obtention de cinétiques de libération d’ibuprofène ralenties à pH acide (gastrique). La dernière partie de ce travail a permis de valider cette dernière hypothèse par la réalisation de formes gastro-résistantes sur le modèle des comprimés MUPS (multiple unit pellet system). Les résultats de ce travail exploratoire démontrent que les protéines de soja, associées à un procédé de mise en forme multi-particulaire couplé à de la compression directe, peuvent constituer une alternative biosourcée, respectueuse de l’environnement (manipulation en solvant aqueux, temps de séchage et étapes de compression réduits) et sûre à l’enrobage utilisé dans les formes gastro-résistantes traditionnelles.

Encapsulation is a novel technique that involves the entrapment of materials such as cells, enzymes or chemicals within a semi-permeable matrix and is being explored as a drug delivery system. This project investigated the encapsulation of Streptomyces nodosus in alginate to assess whether this organism can produce the antifungal drug amphotericin B from within the matrix. New methods were developed to immobilise S. nodosus mycelia and spores in alginate capsules, assess bacterial viability and detect ng mL–1 quantities of amphotericin B in culture fluids. When capsules were cultured and cell proliferation was encouraged, organisms formed protrusions on the surface of the capsules. Differentiated branched hyphae that never progressed to sporogenic hyphae were observed on the surface of these structures. Viability was maintained for up to 30 days and low levels of amphotericin B were produced. The emergence of a co-existing free-dwelling population was also observed. Culturing immobilised organisms using conditioned media from an amphotericin deficient S. nodosus strain, augmented the development of the free-dwelling population resulting in the detection of amphotericin B in the culture fluid and full differentiation to sporogenic hyphae. This is the first report of sporulation of S. nodosus in liquid environments and demonstrates that immobilised S. nodosus can produce antibiotics. The sporulation of free-dwelling organisms was also induced using conditioned media and manipulation of quorum size, indicating a solid surface is not required for sporulation. Conditioned media from other Streptomyces spp. induced variable responses including sporulation, pigment formation and antibiotic production, possibly demonstrating communication between species and/or alteration in nutritional status. This new model for the life cycle of S. nodosus will permit the study of developmental pathways, antibiotic production, microbial community structure and inter-species and intra-species signalling. / Doctor of Philosophy (PhD)

In this study, strains of probiotic bacteria have been selected for tolerance to low pH, bile, sucrose, oxygen in media and low storage temperatures. Lactobacillus acidophilus 2401 and Bifidobacterium infantis 1912 were selected as strains able to survive in these conditions. These two strains were then offered further protection from the adverse conditions of food processing and storage by microencapsulation in a calcium alginate and starch gel matrix. Encapsulation in calcium alginate increases survival in yoghurt. In cheddar cheese the free L. acidophilus 2401 and B. infantis 1912 cells survived better than the encapsulated cells, probably due to the dense nature of the cheddar cheese matrix combined with the encapsulation restricting the flow of the nutrients and metabolites between the outside environment and the cells. In ice cream survival was high, probably due to the high fat and solids nature of the ice cream combined with the low storage temperature. The trial results of the laboratory scale production was consistent with the survival results for yoghurt and cheddar cheese. Incorporation of encapsulated probiotic bacteria into ice cream and cheddar cheese was acceptable by sensory standards and largely unnoticeable in comparison with the same foods without capsules. The capsules were visible and able to be felt on the tongue when eaten in yoghurt causing the product to be disliked by the panellists. / Master of Science (Hons)

<p>Transplantation of islets of Langerhans is a potential treatment of type 1 diabetes that aims to restore normal glucose homeostasis. Microencapsulation of islets could enable transplantation in the absence of immunosuppression, which would be beneficial as the side effects associated with immunosuppression outweigh the potential benefits of islet transplantation. Alginate is a polysaccharide that can be harvested from brown algae and is often used for microencapsulation of cells.</p><p>The aim of this study was to evaluate alginate/poly-L-lysine/alginate capsules with regard to their biocompatibility and permeability to cytokines. Moreover, the function of microencapsulated islets was studied <i>in vitro</i> as well as their ability to reverse hyperglycaemia in diabetic mice.</p><p>Microencapsulated rodent islets functioned well <i>in vitro</i>, with similar insulin release rates and glucose oxidation rates as naked islets. However, when cultured with interleukin-1β and tumour necrosis factor-α, microencapsulated islets were functionally suppressed, showing that the capsules are permeable to these cytokines. The biocompatibility of capsules varied depending on their composition. The presence of poly-L-lysine in the capsule decreased the biocompatibility. However, the biocompatibility of the capsules was improved when the coating alginate had been epimerised, i.e. enyzmatically tailored. Transplantation of microencapsulated allogeneic islets to immune competent mice lowered blood glucose concentrations up to 1 month after implantation. The success of the microencapsulated islet graft depended on the composition of the alginate/poly-L-lysine/alginate capsule used, as capsules that had poor biocompatibility failed to reverse hyperglycaemia more than transiently in athymic nude mice.</p><p>In conclusion, alginate/poly-L-lysine/alginate capsules can protect islets of Langerhans from allogeneic rejection in mice. However, the composition of the capsule is of critical importance in the success of transplantation. Epimerised alginates may provide a novel capsule with ideal properties for microencapsulation of islets of Langerhans.</p>

Transplantation of islets of Langerhans is a potential treatment of type 1 diabetes that aims to restore normal glucose homeostasis. Microencapsulation of islets could enable transplantation in the absence of immunosuppression, which would be beneficial as the side effects associated with immunosuppression outweigh the potential benefits of islet transplantation. Alginate is a polysaccharide that can be harvested from brown algae and is often used for microencapsulation of cells. The aim of this study was to evaluate alginate/poly-L-lysine/alginate capsules with regard to their biocompatibility and permeability to cytokines. Moreover, the function of microencapsulated islets was studied in vitro as well as their ability to reverse hyperglycaemia in diabetic mice. Microencapsulated rodent islets functioned well in vitro, with similar insulin release rates and glucose oxidation rates as naked islets. However, when cultured with interleukin-1β and tumour necrosis factor-α, microencapsulated islets were functionally suppressed, showing that the capsules are permeable to these cytokines. The biocompatibility of capsules varied depending on their composition. The presence of poly-L-lysine in the capsule decreased the biocompatibility. However, the biocompatibility of the capsules was improved when the coating alginate had been epimerised, i.e. enyzmatically tailored. Transplantation of microencapsulated allogeneic islets to immune competent mice lowered blood glucose concentrations up to 1 month after implantation. The success of the microencapsulated islet graft depended on the composition of the alginate/poly-L-lysine/alginate capsule used, as capsules that had poor biocompatibility failed to reverse hyperglycaemia more than transiently in athymic nude mice. In conclusion, alginate/poly-L-lysine/alginate capsules can protect islets of Langerhans from allogeneic rejection in mice. However, the composition of the capsule is of critical importance in the success of transplantation. Epimerised alginates may provide a novel capsule with ideal properties for microencapsulation of islets of Langerhans.

Transplantation of pancreatic islets is a potential treatment of type 1 diabetes that aims to restore normal blood glucose control. By encapsulating the islets in alginate, they can be protected from rejection. The aim of this thesis was to study the biology of encapsulated islets and to use the technique of microencapsulation to study the effect of transplantation in a system that is separated from direct contact with the vascular system and the host tissue at the transplantation site. Encapsulated islets can effectively reverse hyperglycaemia after transplantation into the peritoneal cavity of diabetic mice. A period of culture before encapsulation and transplantation did not affect their insulin release or curative capability. Pre-culture with exendin-4 improved insulin secretion, but not to the extent that the long term outcome in our transplantation model was improved. Despite being able to reach and retain normoglycaemia, microencapsulated islets transplanted intraperitoneally decreased in size. More specifically the number of beta cells in each individual islet was decreased. However, in contrast to previous studies using non-encapsulated islets, the alpha cell number was maintained, and thus the capsule seems to protect these peripherally located and otherwise exposed cells. As the capsule also prevents revascularisation of the islets, the model was used to study the importance of vascular supply for islet amyloid formation. Islet amyloid is a possible reason for the long-term failure of transplanted islets. It is likely that their low vascular density causes a disturbed local clearance of IAPP and insulin that starts the aggregation of IAPP. Indeed, encapsulated islets had an accelerated amyloid formation compared to normal islets, and might serve as a model for further studies of this process. In conclusion, although revascularisation is not a prerequisite for islet graft function, it plays an important role for islet transplantation outcome.

The main objective of the study was to encapsulate the phenolic compounds from sour cherry pulp in micro size, to investigate the physicochemical properties of capsules and their digestability in simulated gastric and intestinal fluid. The effect of different coating materials, ultrasonication time and core to coating ratio on encapsulation of phenolic compounds from sour cherry pomace was investigated. Maltodextrin and gum Arabic were chosen as coating materials. Coating material was prepared with different maltodextrin:gum Arabic (MD:GA) ratios of 10:0, 8:2, 6:4 to make the total solid content 10%. In addition, two different core to coating ratios of 1:10 and 1:20 were used. Emulsions were prepared by homogenization through ultrasonication at 160 W power and 20 KHz frequency for different time periods (5-30 min). Then, the emulsions were freeze dried for 48 hours to obtain the microcapsules. Encapsulation efficiency, antioxidant activity, surface morphology, particle size, color, digestability and glass transition temperatures of the microcapsules were determined. The microcapsules with a core to coating ratio of 1:20 were found to have higher encapsulation efficiencies (78.80-92.26%) than those with a core to coating ratio of 1:10 (69.38-77.83%). Increasing the gum Arabic ratio in the coating material increased encapsulation efficiency. Optimum conditions for encapsulation with the highest efficiency and the lowest particle size were sonication time of 22.5 min, MD:GA ratio of 8:2 and core to coating ratio of 1:20. Encapsulation was effective in preventing the release of the phenolic compounds in gastric fluid. On the other hand, phenolic compounds were released from the capsules into the intestinal fluid.