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|Title:||Drying kinetics of biofilms obtained from chestnut starch and carrageenan with and without glycerol|
Torres, M. D.
Prieto, D. M
Sousa, A. M. M.
Gonçalves, M. P.
Silva Blanco, C.
|Publisher:||Taylor and Francis|
|Abstract(s):||Drying kinetics of biofilms from chestnut starch and hybrid carrageenan were experimentally determined and modelled. The biofilms were obtained by mixing the respective solutions (4.0% w/w) of both substances in the proportion 80/20 of chestnut starch/hybrid carrageenan. Glycerol (at 5.0% w/w) was added to some biofilms. Biofilms were prepared using a casting method. Drying kinetics were performed at 30, 40, and 50 C for forced air convection (1.8 0.1 m/s) and 30 and 50 C for natural convection. Constant drying rate period, above critical moisture content (5.4 and 4.2 kg water/kg d.b. without and with glycerol, respectively) allowed the evaluation of the heat transfer coefficients. The water diffusion coefficients were determined in the falling rate period assuming a semi-infinite slab with variable thickness. Water sorption isotherms of biofilms at 25 C were determined and fitted with the GAB model. Mechanical properties of different biofilms showed no significant differences for Young’s modulus values (44.0 4.6 MPa). Nevertheless, films prepared at 30 C under natural drying showed the lowest values of tensile strength and elongation (32.2 4.9MPa and 0.85 0.11%).|
|Appears in Collections:||IPC - Artigos em revistas científicas internacionais com arbitragem|
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