Artigo Produção Nacional Revisado por pares

Zein films with unoxidized or oxidized tannic acid

2017; Wiley; Volume: 97; Issue: 13 Linguagem: Inglês

10.1002/jsfa.8327

ISSN

1097-0010

Autores

Talita M. Santos, Men de sá M. Souza Filho, Celli Rodrigues Muniz, J. P. S. Morais, Lloyd Ryan Viana Kotzebue, André Luís Sousa Pereira, Henriette Monteiro Cordeiro de Azeredo,

Tópico(s)

Microplastics and Plastic Pollution

Resumo

Abstract BACKGROUND Corn zein is a predominatly hydrophobic protein, forming films with relatively good water resistance. Tannic acid, especially in its oxidized form, is supposed to cross‐link proteins including zein, which may be explored to further enhance the water resistance of zein films. The effects of different contents (0–8 wt%) of unoxidized and oxidized tannic acid ( uTA and oTA , respectively) on the properties of zein films at different pH values (4–9) were studied, according to central composite designs. RESULTS Increasing tannic acid contents and pH values resulted in decreased water solubility and increased tensile strength and modulus of films. The presence of tannic acid provided the films with a yellowish color and increased opacity. Paired t ‐tests indicated that oTA films presented higher tensile strength, lower water vapor permeability and lower water solubility than uTA films. CONCLUSION Higher tannic acid contents and pH values resulted in films with better overall physical properties, which might be ascribed to cross‐linking, although the films were still not water resistant. The resulting films have potential to be used for food packaging and coating applications. © 2017 Society of Chemical Industry

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