Thèse de doctorat : Génie des procédés : Vandoeuvre-les-Nancy, INPL : 2005. / Titre provenant de l'écran-titre. Bibliogr.

Orientadora: Ivanise Guilherme Branco / Banca: Cassia Roberta Malacrida Mayer / Banca: Izabel Cristina Freitas Moraes / Resumo: As algas marinhas pardas são as principais fontes de alginato de sódio utilizados na indústria alimentícia. O Brasil não possui o processamento de alginato, sendo assim dependente de produtos importados para suprir a demanda. A macroalga Sargassum sp. é comumente encontrada nas regiões costeiras do litoral de São Paulo, a extração de alginato dessa alga possibilitaria autonomia brasileira na produção de alginato de sódio. O meio ambiente e as condições climáticas em que as algas marinhas vivem influencia no rendimento de alginato, na massa molecular e na capacidade antioxidante. No primeiro capítulo foi realizado a otimização da extração de alginato de sódio por delineamento Box-Behnken e também o estudo da influência dos parâmetros de pH, temperatura e tempo de extração sobre o rendimento, viscosidade intrínseca e massa molecular. O pH influencia no rendimento, viscosidade intrínseca e massa molecular, enquanto que o tempo apresentou baixo efeito sobre o rendimento e a temperatura não influenciou nas respostas avaliadas. Os resultados da otimização mostraram que máximo rendimento (46,04%), viscosidade intrínseca (4,89 dL/g) e massa molecular (231,78 kDa) podem ser obtidos utilizando na extração a temperatura de 80°C, pH 10 por 90,08 minutos. No segundo capítulo foram estudados alginatos extraídos de Sargassum cymosum C. Agardh coletadas em duas localidades diferentes do litoral de São Paulo (Ubatuba-ASU e São Sebastião-ASS) com relação ao rendimento, massa molecular, compor... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brown seaweeds are the main sources of sodium alginate used in the food industry. Brazil doesn't have alginate processing, so it is dependent on imported products to supply the demand. The macroalgae Sargassum sp. is commonly found in the coastal regions of São Paulo, the extraction of alginate from this alga would allow Brazilian autonomy in the production of sodium alginate. The environment and climatic conditions in which marine algae live influence alginate yield, molecular weight and antioxidant capacity. In the first chapter, the optimization of the sodium alginate extraction by the Box-Behnken design was carried out, as well as the influence of pH, temperature and extraction time parameters on yield, intrinsic viscosity and viscosimetric molecular mass. pH influenced yield, intrinsic viscosity and molecular mass, while time had low effect and temperature did not influence the responses evaluated. The optimization results showed that maximum yield (46.04%), intrinsic viscosity (4.89 dL / g) and viscosimetric molecular weight (231.78 kDa) can be obtained using the extraction at temperature of 80 ° C, pH 10 and 90 minutes. In the second chapter, alginates extracted from Sargassum cymosum C. Agardh were studied in two different locations along the coast of São Paulo (Ubatuba-ASU and São Sebastião-SSA) and were studied the difference between them in the yield, molecular mass, rheological behavior and antioxidant activity. The yield presented higher values for the alginates ... (Complete abstract click electronic access below) / Mestre

Les alginates sont des polysaccharides naturels extraits des algues brunes, capables de réticuler instantanément en formant un gel au contact des ions calcium. L'objet de cette thèse est d'utiliser ces alginates au sein de formulations détergentes capables de dégraisser les surfaces de matériaux composites usinés. Les solutions détergentes sont spécifiquement formulées pour être compatibles avec les alginates afin d'empêcher leur dégradation tout en permettant leur réticulation après action détergente. La faisabilité du procédé a été démontrée et ses paramètres critiques ont été identifiés et étudiés.Le principal avantage de ce procédé est qu'il permet, contrairement aux solutions de dégraissage lessivielles traditionnelles, de ne pas gaspiller d'eau tout en offrant un moyen rapide et efficace de dégraisser les surfaces. / Abstract

Purpose: To assess and measure the compatibility of irreversible hydrocolloids (alginates) readily available in South Africa with available gypsum products by testing the quality reproducibility of lines on a standard die. Method: Under controlled laboratory conditions six brands of alginate impression material were tested against six types of gypsum products using the EN 21563:1991 (ISO 1563:1990) recommended protocol. Photomicrographs of the resultant gypsum surfaces were taken and a scoring method similar to that described by Owen (1986b) was used by previously calibrated independent examiners in order to evaluate the acceptable alginate/gypsum combinations. Results: There was an unexpected variability in the rater scores, and considerable variability in the quality of the casts from the various possible alginate/gypsum combinations. Statistical analysis allowed for the use of combination mean scores taking into account all the scores of all the raters, but discrimination was limited to those combinations with the best scores. The best possible score was 3 and the worst 12. In light of the inter-rater variability the combinations with scores of 4 or less were considered to be the recommended combination for clinical application. No alginate proved to be universally compatible with all the gypsum products tested and no gypsum product was universally compatible with all alginates. Conclusion: This study has highlighted the fact that not all alginates are compatible with all gypsum products, and that it is possible to find appropriate combinations for the clinical requirements of a dental cast. However, the fact that there were nine combinations which scored in the very worst category means that manufacturers of alginates should recommend specific gypsum products with which they are compatible and which were used to obtain their ISO rating, and clinicians should be more aware of the need for compatibility.

Orientadora: Ivanise Guilherme Branco / Banca: Cassia Roberta Malacrida Mayer / Banca: Izabel Cristina Freitas Moraes / Resumo: O alginato, presente na parede celular das algas marinhas pardas, apresenta coloração marrom, sendo necessário seu branqueamento para melhor aceitabilidade do mercado consumidor. O gás ozônio (O3) tem mostrado grande potencial de aplicabilidade como agente clareador mais sustentável. O presente estudo visa a otimização, utilizando a análise de superfície de resposta, dos parâmetros de clareamento (tempo, fluxo de oxigênio e temperatura), utilizando ozônio como agente branqueador, sobre os parâmetros colorimétricos (porcentagem de transmitância e índice de luminosidade), composição química (razão entre os ácidos manurônico (M) e gulurônico (G) M/G) e propriedades reológicas (viscosidade dinâmica, viscosidade intrínseca e massa molar) do alginato de sódio extraído de algas pardas (Sargassum spp.). Nas condições otimizadas de clareamento também foi verificada a influência da ozonização sobre a atividade antioxidante do alginato. O tempo é a variável independente que apresentou maior influência nas respostas, seguido da temperatura e fluxo de oxigênio. A condição otimizada encontrada foi um tratamento com fluxo de oxigênio de 2 L/min por 35 minutos à 25oC. A amostra clareada na condição otimizada apresentou capacidade antioxidante maior que a amostra comercial, indicando que o processo de clareamento por ozonização pode ser menos prejudicial aos compostos bioativos. Além disso, os antioxidantes naturais presentes no alginato de sódio aqui estudado podem agregar valor aos produtos que utilizam esse composto em preparações alimentícias / Abstract: Alginate is a polysaccharide which can be found in the cell wall of brown algae. Its original color is brown that is why a bleaching process is needed to improve this visual impairment. The ozone gas (O3) has shown a great potential as a more sustainable bleaching agent. The present study aims the optimization of bleaching parameters (time, oxygen flow rate and temperature) of sodium alginate from brown seaweeds (Sargassum spp.) using ozone gas as the bleaching agent on the colorimetrics parameters (percent transmittance and index of luminosity), chemical compositon (mannuronic (M) and guluronic (G) acid ratio M/G) and rheological properties (intrinsic viscosity, dynamic viscosity and molar mass). Once it was found the optimal conditions of bleaching, it was also verified the influence of ozonation on antioxidant activity of sodium alginate. The findings point out that ozonation time is the independent variable that most affects the responses, followed by the temperature and oxygen flow rate. The optimized bleaching conditions were determinated with an oxygen flow rate at 2 L/min, during 35 min at 25oC. The bleached sample on the optimized conditions presented a higher antioxidant capacity than the commercial sodium alginate sample, highlighting that the discoloration by ozone might be less harmful to bioactive compounds. Besides, natural antioxidants of sodium alginate can add value to products that use this compound in food preparations / Mestre

Purpose: The aim of this thesis was to investigate a novel method of preparing crosslinked alginate matrices. Current methods use large quantities of water and hence are not suitable for large scale manufacturing of drug alginate particulate systems. Moreover, the current processes offer little scope for control of the crosslinking process. The aim was to overcome these problems through studies of paracetamol alginate granular matrices prepared by the novel method and to explore if these granules could be used to improve the taste of paracetamol. Methods: The novel method involves preparation of dried drug alginate granules (moisture content: <5-6 %) using conventional granulation followed by crosslinking treatment of the dried granules with calcium chloride or a combination of calcium and magnesium ion solution in a crosslinking bath. The effect of the process (shear rate, binder quantity) to prepare untreated granules, composition of the raw materials (drug particle size and type of alginate) and subsequently the crosslinking treatment process variables (Ca�⁺ ion concentration, agitation rate, time and temperature of Ca�⁺ solution) on the physicochemical properties of granule systems were studied using factorial designs together with supporting studies. The granules were characterized using sodium and calcium content analysis, drug release studies (mainly sub-60s release) matrix swelling rate and equilibrium swelling studies, tensile strength studies, ion permeation studies, SEM and X Ray analysis and gravimetric studies. Sensory studies correlating sub-60 s drug release (determined using a specially designed apparatus) and human taste scores (measured using an analogue scale) were then undertaken. Selected formulations were evaluated for taste improvement and to determine if mucoadhesion led to an increased unpalatability of paracetamol. Results: Of the crosslinking treatment factors, the calcium concentration had the greatest effect on crosslinked granules. Although other treatment factors also affected the granule properties, alteration of the salt concentration allowed considerable control over the crosslinking process (not possible in the conventional method) in addition to providing a mechanistic understanding of the crosslinking process in the dried state. The use of low calcium concentrations (< 20 mg/ml, CaCl₂. 2H₂O) during treatment led to granule erosion (hence drug loss) due to overall incomplete crosslinking but led to a reduction in the short-term drug release compared to the granules treated with intermediate (100- 250 mg/ml) or high calcium concentrations (>400 mg/ml) due to reduction in the granule porosity after crosslinking. Although intermediate calcium concentrations led to complete crosslinking and longer release times (T 85 %: 25 min) high calcium crosslinking restricted the crosslinking to the surface of the granules leading to faster drug release (T 85 %: 8 min) with low calcium granules showing intermediate crosslinking and drug release rates (T 85 %: 18 min). High calcium treatment limited drug loss during crosslinking (95 % recovered compared to 83 % recovery at intermediate calcium concentration) without affecting the short-term drug release much. Low calcium granules showed the lowest drug recovery (< 70 %) and slowest sub-60s drug release followed closely by intermediate and high calcium treated granules. The granule preparation factors (shear rate, binder quantity) and type of alginate used, considerably affected the sub-60s drug release by affecting surface porosity especially when a low shear rate was used. However, these factors only slightly reduced the drug loss during crosslinking treatment phase (about 4 % increase in drug recovery). Smaller drug particle size had a slightly larger incremental effect on drug recovery (about 8 % increase in the drug recovery) during crosslinking treatment due to better embedding of the drug particles inside the untreated granule matrix. This was true as long as the particle size of the drug was > 98 [mu]m. Below this size drug recovery remained unaffected by changes in drug particle size. Although granule surface porosity considerably affected the sub-60s drug release, its effect on drug release (long-term) was much less. A linear correlation was observed between the sub-60s drug release and sensory scores despite high individual variability. Both granule formulations evaluated showed taste improvement and mucoadhesion did not lead to an increase in the bitter taste of the uncrosslinked paracetamol alginate granules. Conclusions: Unlike the traditional method, the new technique of preparation of crosslinked drug alginate particulate systems uses very little water and allows greater control over the the crosslinking process compared to the swollen state crosslinking. The novel process of preparation is versatile, and should be scalable. It offers the formulator a platform to prepare a matrix, reservoir or a combination of these two systems using alginates and other drugs and polymers as well. Adequate short-term control over paracetamol release, very little loss of paracetamol during treatment (< 5 % loss), reduction in mucoadhesion of the granules and lastly improvement of the taste of paracetamol is possible using alginate based systems especially if high calcium is used during the crosslinking treatment. Hence, it is likely that these taste-improved granules could be used to prepare tablets without the need for a protective film coating to improve taste. Finally, this research established the utility of short-term drug release in taste improvement research and characterization of solid controlled release dosage forms.

Soluble surimi wash water (SWW) proteins could be recovered using chitosan (Chi) complexed with alginate (Chi-Alg) generating co-products for feed formulations. Chi with a degree of deacetylation (DD) of 84% complexed with Alg at a mixing ratio (MR) of 0.2 was used to study Chi-Alg concentration and treatment time protein recovery effects. Insoluble SWW solids were removed by centrifugation and the supernatant was then adjusted to pH 6. Flocculation at 20��C using Chi-Alg at 20, 40, 100 and 150 mg/L SWW was aided by 5 mm agitation and holding for 30 mm, 1h and 24h. Concentration had an effect between low (20 and 40 mg/L) and high (100 and 150 mg/L) levels. Time had an effect between 30 min and 1h but not between 1 and 24 h. Turbidity reduction was affected only by concentration. 100 mg Chi-Alg/L SWW for 1 h achieved 83% protein adsorption and 97% turbidity reduction while lower concentrations yielding higher adsorption required longer times. Fourier Transform Infrared (FTIR) analysis of untreated and Chi-Alg treated SWW solids confirmed protein adsorption. Amide band areas normalized against a common 3005-2880 cm����� region confirmed the high protein recovery by 100 mg Chi-Alg/L SWW. Six Chi samples differing in molecular weight (MW) and degree of deacetylation (DD) were tested to recover soluble SWW solids using 20, 40, and 100 mg Chi-Alg/L SWW (0.2 MR, 1h). High (94%, 93%) and low (75%) DD chitosan had lower protein adsorption (73-75%) when compared to the intermediate (84%) DD chitosan (74-83%). Intermediate DD and high MW Chi seemed to perform better; however, SY-1000 with 94% DD did not follow this trend (79-86% protein adsorption, 85-92% turbidity reduction). Insoluble SWW (P1) and soluble solids (P2) recovered using 150 mg Chi- Alg/L SWW contained 61.4 and 73.1% protein, respectively. Rat diets formulated with 10% protein substitution by P1 and 10% and 15% by P2 had acceptability and protein efficiency ratios (PER) as high as the casein control with no deleterious effects. Rat diets with 100% P2 protein substitution showed higher PER and net protein ratio than the casein control with no deleterious effects. Protein recovered from SWW using Chi-Alg has the potential to be used in commercial feed formulations. / Graduation date: 2004

Thèse de doctorat : Génie des procédés et des produits : INPL : 2007. / Titre provenant de l'écran-titre.

Reproduction de : Thèse d'exercice : Chirurgie dentaire : Nantes : 2009. / Bibliogr.

Purpose: The aim of this thesis was to investigate a novel method of preparing crosslinked alginate matrices. Current methods use large quantities of water and hence are not suitable for large scale manufacturing of drug alginate particulate systems. Moreover, the current processes offer little scope for control of the crosslinking process. The aim was to overcome these problems through studies of paracetamol alginate granular matrices prepared by the novel method and to explore if these granules could be used to improve the taste of paracetamol. Methods: The novel method involves preparation of dried drug alginate granules (moisture content: <5-6 %) using conventional granulation followed by crosslinking treatment of the dried granules with calcium chloride or a combination of calcium and magnesium ion solution in a crosslinking bath. The effect of the process (shear rate, binder quantity) to prepare untreated granules, composition of the raw materials (drug particle size and type of alginate) and subsequently the crosslinking treatment process variables (Ca�⁺ ion concentration, agitation rate, time and temperature of Ca�⁺ solution) on the physicochemical properties of granule systems were studied using factorial designs together with supporting studies. The granules were characterized using sodium and calcium content analysis, drug release studies (mainly sub-60s release) matrix swelling rate and equilibrium swelling studies, tensile strength studies, ion permeation studies, SEM and X Ray analysis and gravimetric studies. Sensory studies correlating sub-60 s drug release (determined using a specially designed apparatus) and human taste scores (measured using an analogue scale) were then undertaken. Selected formulations were evaluated for taste improvement and to determine if mucoadhesion led to an increased unpalatability of paracetamol. Results: Of the crosslinking treatment factors, the calcium concentration had the greatest effect on crosslinked granules. Although other treatment factors also affected the granule properties, alteration of the salt concentration allowed considerable control over the crosslinking process (not possible in the conventional method) in addition to providing a mechanistic understanding of the crosslinking process in the dried state. The use of low calcium concentrations (< 20 mg/ml, CaCl₂. 2H₂O) during treatment led to granule erosion (hence drug loss) due to overall incomplete crosslinking but led to a reduction in the short-term drug release compared to the granules treated with intermediate (100- 250 mg/ml) or high calcium concentrations (>400 mg/ml) due to reduction in the granule porosity after crosslinking. Although intermediate calcium concentrations led to complete crosslinking and longer release times (T 85 %: 25 min) high calcium crosslinking restricted the crosslinking to the surface of the granules leading to faster drug release (T 85 %: 8 min) with low calcium granules showing intermediate crosslinking and drug release rates (T 85 %: 18 min). High calcium treatment limited drug loss during crosslinking (95 % recovered compared to 83 % recovery at intermediate calcium concentration) without affecting the short-term drug release much. Low calcium granules showed the lowest drug recovery (< 70 %) and slowest sub-60s drug release followed closely by intermediate and high calcium treated granules. The granule preparation factors (shear rate, binder quantity) and type of alginate used, considerably affected the sub-60s drug release by affecting surface porosity especially when a low shear rate was used. However, these factors only slightly reduced the drug loss during crosslinking treatment phase (about 4 % increase in drug recovery). Smaller drug particle size had a slightly larger incremental effect on drug recovery (about 8 % increase in the drug recovery) during crosslinking treatment due to better embedding of the drug particles inside the untreated granule matrix. This was true as long as the particle size of the drug was > 98 [mu]m. Below this size drug recovery remained unaffected by changes in drug particle size. Although granule surface porosity considerably affected the sub-60s drug release, its effect on drug release (long-term) was much less. A linear correlation was observed between the sub-60s drug release and sensory scores despite high individual variability. Both granule formulations evaluated showed taste improvement and mucoadhesion did not lead to an increase in the bitter taste of the uncrosslinked paracetamol alginate granules. Conclusions: Unlike the traditional method, the new technique of preparation of crosslinked drug alginate particulate systems uses very little water and allows greater control over the the crosslinking process compared to the swollen state crosslinking. The novel process of preparation is versatile, and should be scalable. It offers the formulator a platform to prepare a matrix, reservoir or a combination of these two systems using alginates and other drugs and polymers as well. Adequate short-term control over paracetamol release, very little loss of paracetamol during treatment (< 5 % loss), reduction in mucoadhesion of the granules and lastly improvement of the taste of paracetamol is possible using alginate based systems especially if high calcium is used during the crosslinking treatment. Hence, it is likely that these taste-improved granules could be used to prepare tablets without the need for a protective film coating to improve taste. Finally, this research established the utility of short-term drug release in taste improvement research and characterization of solid controlled release dosage forms.