ABSTRACT Edible films are an alternative to synthetic materials used for packaging foods. The aim of this study was to develop and characterize films made from cassava starch, freeze-dried acai and glycerol. The films were characterized for thickness, water vapor permeability, water solubility, anthocyanins, antioxidant capacity and mechanical properties. The results indicated a rich edible film in anthocyanins with considerable antioxidant capacity (150.70 micromol Trolox), which can extend the commercial validity of the packaged food and meets the growing demand for biodegradable packaging that tends to reduce the environmental impact. The addition results in a significant effect on the polymer matrix reducing the water solubility and water activity. The elongation test at rupture reported to be 17.738%, indicating that addition of pulp increased film flexibility.

Filmes provenientes de biopolímeros (polissacarídeos e proteínas) apresentam-se como alternativa ao uso de derivados petroquímicos, possibilitando a formação de matrizes contínuas, e a otimização de parâmetros como pH e tipo de plastificante pode resultar em materiais com propriedades melhoradas. Neste estudo, filmes de amido de mandioca produzidos por casting foram avaliados quanto a adição de extrato proteico de soja (EPS), glicerol e pH do meio. O aumento da concentração de EPS levou ao escurecimento dos filmes, ao aumento da solubilidade e aumentou o pH. O maior teor de plastificante e o menor pH elevaram a permeabilidade ao vapor de água (PVA). A menor PVA (0,057 g mm h-1 m-2 kPa-1) foi obtida com máximo teor de EPS (47%) e 13% de glicerol em pH 12. A força de perfuração variou de 0,08 a 2,78 N, sendo os maiores valores com adição de EPS e glicerol em nível intermediário (30%) em pH neutro. A maior deformação na perfuração (31,9%) ocorreu no teor de EPS mais baixo (13%) e de glicerol mais alto (47%). Considerando-se os fatores desejáveis: baixa PVA, baixa solubilidade e boa resistência mecânica, os filmes produzidos com 15,2% de EPS, 29,2% de glicerol em pH 6,1 foram os que mais bem atenderam a estas características.

Films from biopolymers (polysaccharides, proteins) are an alternative to the use of petrochemical derivatives, with possible formation of continuous matrices. Upon optimizing parameters such as pH and type of plasticizer, one may obtain materials with improved properties. In this study, cassava starch films produced by casting were evaluated concerning soybean protein extract (SPE) content, glycerol and varied pH conditions. Upon increasing the concentration of SPE, the films became darker, more soluble and the pH increased. The higher plasticizer content and the lower pH increased the water vapor permeability (WVP). The lowest WVP (0.057 mm g mm h-1 m-2 kPa-1) was obtained at the maximum content of SPE (47%) and 13% glycerol at pH 12. The puncture force ranged from 0.08 to 2.78 N and the highest values were obtained with intermediate level of SPE and glycerol (30%) at neutral pH. The highest puncture deformation value (31.9%) occurred at the lowest SPW content (13%) and highest glycerol content (47%). Considering as the desirable factors: low WVP, low solubility and good mechanical strength, one concludes that the films produced from cassava starch with 15.2% of EPS, 29.2% of glycerol at pH 6.1 exhibited the best performance.

Edibles films are an alternative to synthetic materials used for packing food products. Barbados cherry is rich in vitamin C and carotenoids. The aim of this study was to characterize and develop films by casting from cassava starch, lyophilized Barbados cherry pulp and glycerol. The films were characterized with respect to thickness, water vapor permeability (WVP), water solubility, vitamin C, carotene and mechanical properties. The interaction of pulp and glycerol reduced film thickness. An increase in pulp concentration up to 60% increased WVP but beyond this concentration reduced both WVP and solubility leading to an increased level of vitamin C and β carotene in the films.