Comparative study on the properties of flour and starch films of plantain bananas (Musa paradisiaca)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Biodegradable films were prepared by using the flour and starch isolated from plantain bananas of the variety "Terra" (Musa paradisiaca). Since the non-starchy fraction present in the banana flour represents 29.4% (on dry basis) of its composition, we considered it would be interesting to compare the properties of the film elaborated from this natural blend with that of the film produced from the banana starch only. Both films were characterized on the basis of their mechanical, barrier, optical, structural, and thermal properties. The banana flour film was less mechanically resistant but more flexible than the banana starch film. Despite the differences in the microstructure of the flour and starch films, the former was slightly soluble in water, and its water vapor permeability was similar to that of the starch film. Regarding the optical properties, the flour film was yellowish, which can be attributed to its protein content and the presence of phenolic compounds. The starch film, on the other hand, was lighter and less opaque. The FTIR spectra revealed the presence of the amide I group related to proteins only in the case of the flour film. Both plantain banana films displayed a C-type X-ray pattern and one glass transition temperature each, which was higher for the starch film (46.4 degrees C) as compared to the flour film (30.2 degrees C). The presence of other components (protein, lipids, and fiber) in the flour film had important effects on its properties. In general, the banana flour and starch are very promising materials for the formulation of coatings and films. (C) 2012 Elsevier Ltd. All rights reserved.302681690Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Optimization of process conditions for the production of films based on the flour from plantain bananas (Musa paradisiaca)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In this work, the casting process has been employed for the production of flour films from plantain bananas (Musa paradisiaca); glycerol has been used as plasticizer. The influence of process conditions such as the glycerol concentration (Cg), the process temperature (Tp), the drying temperature (Td), and the relative humidity (RH) on the mechanical, barrier, and optical properties of banana flour films has been evaluated by means of a central composite design. The results have been statistically analyzed by the response surface methodology and desirability function, and the optimal process conditions for film formation have been determined. The process variables have a significant impact on the mechanical properties, water vapor permeability (WVP), and opacity of the films, but these features are mostly affected by the Cg parameter. Compared to other biodegradable films, the banana flour film displays high opacity, low solubility in water, good WVP and flexibility, and excellent mechanical strength and rigidity. The desirability function employed here has allowed for the establishment of the optimal process conditions, which are Cg = 19 g of glycerol/IOU g of flour, Tp = 81 degrees C, Td = 54 degrees C, and RH = 48%, proving to be an effective tool for this type of study. Published by Elsevier Ltd.521111Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Estabilidade no prognóstico do perfil de aptidão física de jovens atletas de handebol

Este estudo teve como objetivo: 1) verificar a estabilidade do perfil de aptidão física de jovens atletas de handebol durante a adolescência; e 2) comparar os resultados com a seleção paulista adulta feminina. Para tanto, a amostra foi constituída por cinco jovens atletas de handebol feminino que foram seguidas semilongitudinalmente por dois anos, com média de idade e tempo de prática inicial e final de 14,2 ± 1,3 anos, 18,4 ± 10,7 meses e 16,2 ± 1,3 anos, 42,8 ± 10,7 meses, respectivamente (12h/semana de treinamento). Na temporada de 1997 quatro atletas foram pré-selecionadas para a seleção brasileira de cadetes. As variáveis mensuradas foram: peso corporal (P); altura total (A); impulsão vertical sem (IVS) e com auxílio dos membros superiores (IVC); impulsão horizontal (IH); agilidade (SR); velocidade (50m) e potência anaeróbica (40seg.), seguindo padronização CELAFISCS. Os coeficientes de Pearson e Spearman foram significativamente altos e muitos altos (p < 0,05) para P (0,88), A (0,98 e 0,99), 50m (0,95 e 0,90) e 40seg. (0,87 e 0,90). Estes dados permitem concluir que as jovens atletas apresentaram alta estabilidade nas variáveis antropométricas, velocidade e potência anaeróbica durante um período de dois anos da adolescência, favorecendo a hipótese de que a expectativa de sucesso esportivo pode ser predita em idades precoces