Resumo

NAVIA, DIANA P; AYALA A, ALFREDO  e  VILLADA, HÉCTOR S. ADSORPTION ISOTHERMS OF CASSAVA FLOUR BIOPLASTICS COMPRESSION MOLDED. Rev.Bio.Agro [online]. 2011, vol.9, n.1, pp.77-87. ISSN 1692-3561.

Water adsorption and isosteric heat were evaluated in biopolymers made from flour of two varieties of cassava (CM 7951-5 and MBRA 383), fique dust and glycerol by compression molding technique. The adsorption isotherms of polymeric samples were performed at 15,25, and 35°C in a water activity range of 0.12 to 0.98, using a gravimetric method. The adsorption experimental data were adjusted using the GAB, Caurie, Oswin, Smith, Henderson and Peleg models. The sorption isosteric heat (Qst) was determined with Clausius-Clapeyron equation. The results showed that the Peleg model was adjusted appropriately to experimental values of adsorption at 15, 25 and 35°C in the samples prepared with the variety CM 7951-5 and 15 and 25°C for the variety MBRA 383, while the GAB model was at 35°C for MBRA 383. Isosteric heat of sorption decreased with increase in equilibrium moisture content finding the maximum in 87Kj/mol and 78 Kj/mol, and minimum in 44.6 Kj/mol and 44.5 Kj/mol in samples made with CM 7951-5y MBRA 383 respectively.

Palavras-chave : Adsorption; Compression molding; Cassava; Biopolymers.

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