Patrícia Tanada-Palmu

Efeito da adição de ácidos graxos em filmes à base de pectina

Os objetivos deste trabalho foram desenvolver filmes a base de pectina de baixo teor de esterificacao, amidada, com adicao dos acidos graxos laurico (AL), palmitico (AP) e estearico (AE) e caracteriza-los quanto as propriedades de permeabilidade ao vapor de agua (PVA) e ao oxigenio, propriedades mecânicas (tensao de ruptura e elongacao), solubilidade em agua e opacidade, alem de observar a morfologia da superficie dos filmes utilizando microscopia eletronica de varredura (MEV). A adicao de 12 e 18% dos acidos promoveu aumento da PVA e da elongacao e reducao da tensao de ruptura, em relacao aos filmes com 6% de acido graxo. Todos os filmes apresentaram-se 100% soluveis em agua e mais opacos quando os acidos graxos foram adicionados. A partir da MEV, foi observado que os acidos graxos nao se incorporaram a matriz filmogenica.

Filmes compostos de gelatina, triacetina, ácido esteárico ou capróico: efeito do pH e da adição de surfactantes sobre a funcionalidade dos filmes

The development of biofilms has grown considering the possibility of partial substitution of plastic materials which are not biodegradable. Proteins and polysaccharides have been used to produce films with good mechanical properties. However, films produced with these materials present a high permeability in water vapor. An alternative to improve the water vapor barrier of films is to incorporate hydrophobic substances (stearic and caproic fatty acids) in the composition of the filmogenic solution, however this incorporation does not occur homogeneously. Thus, to improve the incorporation of hydrophobic substances in the protein matrix of the film, surfactants (SDS and Tween 80) were added. They are compounds that improve the interaction between the protein and the fatty acids, producing a less heterogeneous filmogenic matrix. The effect of pH was also studied, with the purpose of observing if it influences the homogeneity of the filmogenic matrix. The addition of stearic acid to the gelatin-based films was more efficient in reducing the water vapor permeability than the caproic acid. Adding surfactant SDS reduced water vapor permeability of both films, with stearic acid or caproic acid. Adjusting the pH to the films with no surfactants produced more homogeneous matrices.

Production of a banana (Musa cavendishii) extract containing no polyphenol oxidase by ultrafiltration

The objective of this research was the production of a banana extract containing no polyphenol oxidase by ultrafiltration. Banana juice was extracted after inhibition of polyphenol oxidase using a solution containing 0.15 g per 100 ml of sodium metabisulphite and 1 g per 100 ml of ascorbic acid in distilled water to avoid initial browning. Polyphenol oxidase was then retained by ultrafiltration using polysulphone membranes with a cut-off of 20 kDaltons. Two transmembrane pressures, 600 and 800 kPa, were used but 600 kPa was preferred because of the more stable permeate flux which decreased less with time and concentration of extract. © 1999 Society of Chemical Industry

Vigor de sementes de brócolos submetidas a coberturas biodegradáveis e micronutrientes

The development and application of biodegradable coatings and films have been used for many years in order to improve quality of the coated or packed product. The development and characterization of pectin and pectin/gelatin-based biofilms with fatty acids was evaluated and verified their efficiency as coatings to broccoli seeds (Brassica oleracea L. var. italica). The solubility in water of the films was determined. The counting and visual observations of the germinated broccoli seeds were done each three days and fresh and dried weight of the plants were determined at the end of the experiment. Pectin-based films with stearic acid were 100% soluble in water and composite films of pectin and gelatin were 18%. The application of the biodegradable coatings on broccoli seeds had no effect on the plants development, showing their potential for commercial use. The fertilizers, sodium molibdate (0.2mg L-1) and boric acid (1mg L-1), added to the coating solution had no interference in the emergence and development of the broccoli plants.

Recobrimento de sementes de brócolos e salsa com coberturas e filmes biodegradáveis

COVERING BROCCOLI AND PARSLEY SEEDS WITH BIODEGRADABLE FILMS AND COATINGS The objective of this work was to compare the performance of broccoli and parsley seeds coated or adhered to biodegradable films of gelatin and chitosan. Initially, the optimum number of coating layers and the thickness of the film were determined in order not to affect the germination of seeds. The performance was evaluated by germination capacity and vigor, and by fresh and dry weight of plants with 30 days. The seeds inserted into the films of gelatin and chitosan showed lower germination results than the control seeds. The coating of the seeds with gelatin and chitosan coatings of had good results in terms of vigor and development of plants. The results indicated that coating the seeds with biodegradable coatings can be promising due to the improvement of the germination of the coated seeds and the development of the plants when compared to the seeds with not treated.