97 research outputs found

    The use of electric fields for edible coatings and films development and production: A review

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    Edible films and coatings can provide additional protection for food, while being a fully biodegradable, environmentally friendly packaging system. A diversity of raw materials used to produce edible coatings and films are extracted from marine and agricultural sources, including animals and plants. Electric fields processing holds advantage in producing safe, wholesome and nutritious food. Recently, the presence of a moderate electric field during the preparation of edible coatings and films was shown to influence their main properties, demonstrating its usefulness to tailor edible films and coatings for specific applications. This manuscript reviews the main aspects of the use of electric fields in the production of edible films and coatings, including the effect in their transport and mechanical properties, solubility and microstructure.Fundação para a CiĂȘncia e a Tecnologia (FCT), Portugal.Coordenação de Aperfeiçoamento de Pessoal de NĂ­vel Superior (CAPES), Brasil

    Biocomposite films based on Îș-carrageenan/locust bean gum blends and clays : physical and antimicrobial properties

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    The aims of this work were to evaluate the physical and antimicrobial properties of biodegradable films composed of mixtures of Îș-carrageenan (Îș-car) and locust bean gum (LBG) when organically modified clay Cloisite 30B (C30B) was dispersed in the biopolymer matrix. Film-forming solutions were prepared by adding C30B (ranging from 0 to 16 wt.%) into the Îș-car/LBG solution (40/60 wt.%) with 0.3 % (w/v) of glycerol. Barrier properties (water vapour permeability, P vapour; CO2 and O2 permeabilities), mechanical properties (tensile strength, TS, and elongation-at-break, EB) and thermal stability of the resulting films were determined and related with the incorporation of C30B. Also, X-ray diffraction (XRD) was done in order to investigate the effect of C30B in film structure. Antimicrobial effects of these films against Listeria monocytogenes, Escherichia coli and Salmonella enterica were also evaluated. The increase of clay concentration causes a decrease of P vapour (from 5.34 × 10−11 to 3.19 × 10−11 g (m s Pa)−1) and an increase of the CO2 permeability (from 2.26 × 10−14 to 2.91 × 10−14 g (m s Pa)−1) and did not changed significantly the O2 permeability for films with 0 and 16 wt.% C30B, respectively. Films with 16 wt.% clay exhibited the highest values of TS (33.82 MPa) and EB (29.82 %). XRD patterns of the films indicated that a degree of exfoliation is attained depending on clay concentration. Îș-car/LBG–C30B films exhibited an inhibitory effect only against L. monocytogenes. Îș-car/LBG–C30B composite films are a promising alternative to synthetic films in order to improve the shelf life and safety of food products.J. T. Martins, A. I. Bourbon, A. C. Pinheiro and M. A. Cerqueira gratefully acknowledge the Fundacao para a Ciencia e Tecnologia (FCT, Portugal) for their fellowships (SFRH/BD/32566/2006, SFRH/BD/73178/2010, SFRH/BD/48120/2008 and SFRH/BPD/72753/2010, respectively), and B. W. S. Souza acknowledges the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil)

    Teores de minerais em polpas e cascas de frutos de cultivares de bananeira

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    O objetivo deste trabalho foi determinar a percentagem de matĂ©ria seca, o teor de minerais e a capacidade de fornecimento de minerais, com base na ingestĂŁo dietĂ©tica de referĂȘncia na polpa e na casca de frutos verdes e maduros de 15 cultivares de bananeira. Utilizaram-se quatro cachos por cultivar e seis frutos por unidade amostral. Foram coletadas amostras frescas da polpa e da casca, para digestĂ”es sulfĂșricas (0,2 g) e nitroperclĂłricas (0,5 g). Foram determinados: no extrato sulfĂșrico, o N total pelo mĂ©todo Kjeldahl; e, no extrato nitroperclĂłrico, P, K, Ca, Mg, Cu, Mn, Fe, Zn e Se. O P foi determinado por colorimetria, e os demais nutrientes, por espectrofotometria de absorção atĂŽmica. O teor de minerais na polpa e na casca foi expresso com base na mĂ©dia dos dois estĂĄdios. HĂĄ diferenças entre cultivares de bananeira quanto Ă  concentração de macro e micronutrientes na polpa e na casca, mas nĂŁo entre frutos verdes e maduros. A cultivar Terrinha apresentou a maior percentagem de matĂ©ria seca na polpa, e as cultivares Marmelo e Maçã, na casca. Para N, P, Fe, Zn e Cu, a casca apresentou duas vezes o teor da polpa. O teor de K e Mn na casca foi de aproximadamente quatro vezes o da polpa. A polpa da cultivar Caipira (AAA) e a casca das cultivares Prata e Pacovan (AAB) apresentam os maiores teores de minerais

    Plasticizer Effect on Oxygen Permeability of ÎČ-Lactoglobulin Films

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    Oxygen Permeability and Mechanical Properties of Films from Hydrolyzed Whey Protein

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