Development and characterization of alginate and chitosan composite films containing natamycin as antimiotic agent

Orientador: Theo Guenter KieckbuschTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuimicaResumo: Filmes simples de alginato (FA) e filmes compostos de alginato e quitosana nas proporções 82,5:17,5 (FC1) e 65:35 (FC2), de baixo grau de reticulação com cálcio (0,04 g CaCl2.2H2O/g alginato) contendo glicerol como plastificante, foram confeccionados pela técnica de casting. Esses filmes foram submetidos a uma reticulação complementar por imersão durante 30 minutos em uma solução contendo 5g CaCl2.2H2O/100 mL. Filmes FA, FC1 e FC2 com espessura média de 48, 54 e 62 µm, respectivamente, apresentaram massa solubilizada em água de 0,15, 0,19 e 0,23 g/g massa seca, coeficientes de permeabilidade ao vapor de água de 4,04, 4,91 e 7,41 g.mm/m2.dia.kPa, intumescimento em água de 68, 102 e 195% (em massa), tensão na ruptura de 96, 75 e 59 MPa e alongamento na ruptura de 8,4, 12,5 e 17,1%. Esses valores assim como o conteúdo de cálcio e os espectros de FTIR indicaram que, nas condições experimentais utilizadas, a interação do alginato com os íons cálcio foi mais efetiva do que com a quitosana, não havendo indícios de formação de ligação amídica entre o alginato e a quitosana. A análise da Tg por DMA também indicou separação de fases entre os dois polímeros. Os filmes com 35% de quitosana apresentaram estrutura polimérica mais rugosa e heterogênea. As três formulações receberam sorbato de potássio (até 17 g/100g biopolímero) e natamicina (0, 0,5, 1, 2, 4 e 8 g/100g biopolímero) como agentes antimicrobianos, e o efeito antimicótico destes filmes frente às espécies Penicillium roqueforti, Penicillium commune e Debaromyces hansenii foi avaliado através do teste de difusão em ágar. O sorbato de potássio não apresentou efeito inibitório, e a natamicina foi eficiente a partir da concentração de 0,5 g/100g biopolímero para o filme de alginato puro e 1 g/100g biopolímero para os filmes compostos. Ensaios de liberação em água indicaram uma cinética muito lenta de liberação do antimicrobiano, sendo mais lenta para os filmes compostos, provavelmente devido à interações eletrostáticas entre a natamicina e a quitosana. Os coeficientes de difusão da natamicina encontrados foram da ordem de 10-11 cm2/s para FA e FC2 e de 10-12 cm2/s para FC1. A estrutura física menos compacta da matriz polimérica do FC2 acelerou a liberação da natamicina. Nas concentrações testadas, a adição da natamicina influenciou principalmente a cor, transparência, rugosidade e morfologia dos filmes. Os resultados obtidos permitem afirmar que os filmes desenvolvidos contendo natamicina apresentam excelente perspectiva de atuação como filmes ativos (antimicrobianos) para alimentosAbstract: Films composed solely by alginate (FA) and two composite films with different mass proportions of alginate and chitosan, 82.5:17.5 (FC1) and 65:35 (FC2), were obtained by casting. Using glycerol as plasticizer, the films were partially crosslinked by adding calcium chloride (0.04 g CaCl2.2H2O/g alginate) to the film forming solution. The resulting soluble films were further crosslinked by total immersion in a CaCl2 solution (5g CaCl2.2H2O/100 mL) for 30 minutes. FA, FC1 and FC2 with an average thickness of 48, 54 and 62 µm, respectively, exhibited soluble mass in water of 0.15, 0.19 and 0.23 g/g dry matter, water vapor permeability coefficient of 4.04, 4.91 and 7.41 g.mm/m2.day.kPa, swelling in water of 68, 102 and 195% (mass basis), tensile strength of 96, 75 and 59 MPa and elongation at break of 8.4, 12.5 and 17.1%. The tendencies found for the physical properties, complemented with values of calcium content in the films and results of FTIR analysis indicated that under the experimental conditions used, ionic binding of alginate chains with calcium ions was more effective than with chitosan, and no evidence of amidic bonding between alginate and chitosan was found. DMA thermograms also indicated phase separation between the two polymers, showing two Tg's for composite films. Films with higher content of chitosan showed rougher surfaces and less homogeneous polymeric structure. The film formulations received potassium sorbate (up to 17 g/100g biopolymer) and natamycin (0, 0.5, 1, 2, 4 and 8 g/100g biopolymer) as antimicrobial agents, and their antimycotic effect against Penicillium roqueforti, Penicillium commune and Debaromyces hansenii was evaluated by the agar diffusion test. Potassium sorbate did not show inhibitory effect. Natamycin was effective at concentrations as low as 0.5 g/100g biopolymer for alginate film and 1 g/100g biopolymer for composite films. Diffusion experiments in water indicated very slow release kinetics of the antimicrobial, being markedly hindered for the composite films, probably due to electrostatic interactions between chitosan and natamycin. Diffusion coefficients in films were in the order of 10-11 cm2/s for FA and FC2, and 10-12 cm2/s for FC1. The addition of natamycin affected mainly the color, transparency, roughness and morphology of the films, in the tested concentration range. The results showed that the films containing natamycin obtained in the present work show excellent perspectives for acting as active films intended for food applicationsDoutoradoEngenharia de ProcessosDoutor em Engenharia Químic

Phase transitions of frozen Camu-camu (Myrciaria dubia (H.B.K.) McVaugh) pulp: effect of cryostabilizer addition

Camu-camu is a tropical fruit with very high vitamin C content and commercialized as frozen pulp. Enthalpies of freezing, temperatures of the onset of ice melting, and glass transition temperatures of the maximally freeze-concentrated phase (T′g) of camu-camu pulp and of samples containing maltodextrin (DE20) and sucrose were measured by differential scanning calorimetry. Maltodextrin exhibited the largest freeze stabilization potential, increasing T′g from −58.2 °C (natural pulp) to −39.6 °C when 30% (w/w) maltodextrin DE 20 was added. Sucrose showed negligible effect on T′g but enhanced considerably the freezing point depression and less amount of ice was formed33312317sem informaçãosem informaçãoThe authors gratefully acknowledge the financial support from FAEPEX–UNICAM

Heterotrophic Growth Of Green Microalgae Desmodesmus Subspicatus In Ethanol Distillation Wastewater (vinasse) And Lipid Extraction With Supercritical Co2

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Single-cell lipids are obtained frommicroorganisms, including some species of microalgae, which under specific growth conditions are able to accumulate lipids in their biomass. Some species of Desmodesmus, a chlorophyceae microalgae, are considered potential sources of lipids and different cultivation systems, including heterotrophic growth inwastewater, have been proposed. This study evaluated the effect of temperature on heterotrophic growth and lipid productivity of Desmodesmus subspicatus in sugarcane processing wastewater and lipid extraction by supercritical carbon dioxide (SC-CO2). RESULTS: Results indicated lipid production by Desmodesmus subspicatus in the temperature range 15 and 40 degrees C, with the highest lipid productivity (similar to 1100 mg L-1 day(-1)) at 20 degrees C. Lipid extraction yield with SC-CO2 increased from 23 to 45% by increasing pressure from 20 to 30 MPa at 60 degrees C A cell disruption pretreatment (sonication) increased the lipid extraction yield by approximately 17%. Fatty acids profiles of the extracted lipids indicated major fractions of palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2), arachidic acid (20:0) and arachidonic acid (20:4). These characteristics are interesting from the viewpoint of biodiesel production. CONCLUSION: Results suggest the feasibility of the heterotrophic production of Desmodesmus subspicatus biomass intended for lipid accumulation using vinasse, followed by SC-CO2 lipid extraction. (C) 2016 Society of Chemical Industry923563569National Council for Scientific and Technological Development (CNPq)BNDES/FUNTECALGAE BiotecnologiaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Polyvinylchloride (PVC) and natural rubber films plasticized with a natural polymeric plasticizer obtained through polyesterification of rice fatty acid

AbstractThe use of natural plasticizers with low toxicity and good compatibility in several polymer applications has become more attractive. In this study, a natural plasticizer was synthesized in the laboratory by esterification of rice fatty acids and polyols. The resulting product was added to PVC and natural rubber latex films (5% w/w). Mechanical properties of the films, as well as tests of migration and exudation of the plasticizer, were performed in order to evaluate the efficiency of plasticization. Optical microscopy (OM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to characterize the pristine and plasticized polymer. Mechanical tests indicated that the addition of the natural plasticizer resulted in an increase in the elongation at break and a consequent decrease in the tensile strength of the films. The plasticizing effect induced by the natural plasticizer was also confirmed by a glass transition temperature (Tg) shift towards lower temperatures in the plasticized films

Synthesis and application of natural polymeric plasticizer obtained through polyesterification of rice fatty acid

This study includes the synthesis of a new natural plasticizer obtained through esterification reaction of rice fatty acid and polyols, its physicochemical characterization and its preliminary application in polyvinyl chloride (PVC). Monopropylene glycol, octanol and diethylene glycol were used as polyols for esterification reaction. Catalyst Fascat® 4100, was also added. Viscosity, acidity and hydroxyl index, moisture content, molar mass, chemical composition (by FTIR) and color were determined to characterize the natural plasticizer synthesized. The results were compared with a commercial plasticizer (DOA: di-octyl adipate) derived from petrochemical source and synthesized in laboratory. According to the results, except from color, the natural plasticizer presented similar properties of commercially available plasticizers, such as DOA. Mechanical tests indicated that the addition of the natural plasticizer to PVC films resulted in a significant increase on its elongation at break (371.2%) compared to pure PVC film, indicating a possible application for this plasticizer172386391CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES150272/2009-01989/200

Heterotrophic growth of green microalgae Desmodesmus subspicatus in ethanol distillation wastewater (vinasse) and lipid extraction with supercritical CO2

BACKGROUND: Single-cell lipids are obtained frommicroorganisms, including some species of microalgae, which under specific growth conditions are able to accumulate lipids in their biomass. Some species of Desmodesmus, a chlorophyceae microalgae, are considered potential sources of lipids and different cultivation systems, including heterotrophic growth inwastewater, have been proposed. This study evaluated the effect of temperature on heterotrophic growth and lipid productivity of Desmodesmus subspicatus in sugarcane processing wastewater and lipid extraction by supercritical carbon dioxide (SC-CO2). RESULTS: Results indicated lipid production by Desmodesmus subspicatus in the temperature range 15 and 40 degrees C, with the highest lipid productivity (similar to 1100 mg L-1 day(-1)) at 20 degrees C. Lipid extraction yield with SC-CO2 increased from 23 to 45% by increasing pressure from 20 to 30 MPa at 60 degrees C A cell disruption pretreatment (sonication) increased the lipid extraction yield by approximately 17%. Fatty acids profiles of the extracted lipids indicated major fractions of palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2), arachidic acid (20:0) and arachidonic acid (20:4). These characteristics are interesting from the viewpoint of biodiesel production. CONCLUSION: Results suggest the feasibility of the heterotrophic production of Desmodesmus subspicatus biomass intended for lipid accumulation using vinasse, followed by SC-CO2 lipid extraction923563569CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQsem informaçã

Sugarcane vinasse and microalgal biomass in the production of pectin particles as an alternative soil fertilizer

High methoxyl pectin was used as biopolymeric matrix to produce a novel slow release soil fertilizer added with sugarcane vinasse and lipid extracted microalgal (Desmodesmus subspicatus) biomass residue (LMBR). Vinasse acted as the biopolymer solvent, providing greater stability to pectin gel, and as a source of nitrogen (N), potassium (K), calcium (Ca) and magnesium (Mg). LMBR (0.5%) was considered a complementary source of N and micronutrients, copper (Cu), iron (Fe) and zinc (Zn). Compared to blank pectin particles, the particles with vinasse and LMBR showed homogeneous polymer matrix, spherical shapes, higher soluble matter release and enhanced mechanical properties. Scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated the incorporation of microalgal biomass and nutrients from vinasse. Higher rates of biodegradation as well as larger degree of mineralization were found over a period of 36 days for vinasse and LMBR particles. These particles exhibit good perspectives as an alternative fertilizer for agriculture applications and represent an innovative solution for vinasse and LMBR final disposal203322330CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ431509/2016-