Complete factorial planning 2 was applied to identify the influence of the cassava starch(A), glycerol(B) and modified clay(C) content on the water vapor permeability(WVP) of the cassava starch films with the addition of bentonite clay as a filler, its surface was modified by ion exchange from cetyltrimethyl ammonium bromide. The films were characterized by X-ray diffraction(XRD), fourier transform by infrared radiation(FTIR), atomic force microscopy(AFM) and scanning electron microscopy(SEM). The factorial analysis suggested a mathematical model thats predicting the optimal condition of the minimization of WVP. The influence of each individual factor and interaction in the WVP was investigated by Pareto graph, response surface and the optimization was established by the desirability function. The sequence of the degree of statistical significance of the investigated effects on the WVP observed in the Pareto graph was C>B>A>BC>AC. Interactions AB, BC and AC showed that the modified clay was the factor of greater significance.
RESUMO -Foram estudadas coberturas a base de fécula de mandioca, glicerol, lecitina de soja e cera de abelha na evolução da cor e perda de massa de tomates. Formulações com diferentes concentrações de fécula, lecitina de soja e cera de abelha foram aplicadas sobre tomates em estágio de maturação verde. Utilizou-se um percentual de fécula de 3% em massa e 0,3% de glicerol para todas as formulações. Os percentuais de cera de abelha variaram entre 1,0 e 2,0 %; e os de lecitina entre 2,0 e 3,0 %. Os tomates recobertos foram armazenados à temperatura ambiente (27 ± 2 ºC), assim como o grupo de tomates sem cobertura usados como controle. Foram avaliados os parâmetros perda de massa, por gravimetria, e a cor, através de um colorímetro, durante sete dias. Os resultados mostraram que as coberturas a base de fécula de mandioca, lecitina de soja e cera de abelha não foram eficazes na redução da perda de massa dos tomates, porém, retardaram a evolução da cor dos frutos em comparação com o grupo controle.
Lignin is one of the most abundant macromolecules on Earth. Lignins are obtained as by-products from the paper industry and used mostly as fuel. Their diverse composition has limited the development of high added-value applications: however, because of their abundance and sustainable origin, there is a growing interest in using lignins as a raw material and as a replacement for oil derivatives. In order to use lignins in bio-refineries, several processes must be studied and standardized. Lignin fractionation using solvents is a promising process. In this study, lignin from sugar cane bagasse (L1) was fractionated with solvents, and the fractions were characterized to evaluate structural aspects relevant for the production of fibers. L1 was extracted into four fractions with toluene (E1), ethanol (E2), methanol (E3), and dimethyl sulfoxide (DMSO, E4). Fractions E2, E3, and E4, showed only slightly different molar masses and molar mass distribution, but have relevant differences in their structural characteristics and processability. The ethanol extract (E2) provided lignins with a more flexible structure, and electro-spinning resulted in the production of nanofibers with diameters between 60 and 120 nm; the methanol fraction (E3) produced nanospheres with diameters between 90 and 350 nm; the DMSO fraction (E4) covered only a surface with electro-spray. These results show the possibility of developing high added-value applications using fractions of lignin from distinct biomasses or from their combination.
Coating technologies with biopolymeric films of low cost and high efficiency are effective in maintaining the chemical and sensory characteristics and shelf-life extension of several fruits.Films of cassava starch/glycerol were synthesized at different temperature and time conditions (25oC / 60h, 40oC / 5h, 60oC / 3h and 80oC / 2h) in order to decrease the drying time of the filmogenic solutions.SEM analysis (scanning electron microscopy), WVP (water vapor permeability), wettability and mechanical properties were evaluated in order to identify morphological and structural changes in the polymeric matrix in different conditions.Changes in temperature and drying time significantly reduced the roughness and affected the barrier characteristics, effectively improving tensile strength. A reduction of more than 90% in the drying time was identified.
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