Artículo
Abstract:
A modification of the GAB isotherm (Guggenheim-Anderson-De Boer) is proposed in order to correlate the sorption data for water activities higher than 0.9. The proposed isotherm retains the desirable properties of the GAB isotherm, i.e. good fitting in the range of aw between 0.05 and 0.80, and also provides a noticeable improvement in the fitting quality for high values of aw, by introducing a new term with an additional constant. Sorption data for native potato starch and gluten at different temperatures (2 °C, 20 °C, 40 °C and 67 °C) were well correlated for the whole aw range. For starch at 67 °C, the values of the constants of the proposed equation do not follow the same tendency obtained for lower temperatures, suggesting that the structure of the material could be changed due to the high temperature. The proposed isotherm can be of interest in the area of drying given that there are few isotherms that accurately represent sorption data at different temperatures in the zone of high aw. Also, it can be useful to predict other thermodynamic functions. In addition, a new procedure is proposed to determine the isosteric heat by using a second order polynomial for representing the variation of moisture as a function of temperature at a fixed water activity.
Registro:
| Documento: | Artículo |
| Título: | Equilibrium sorption isotherms and thermodynamic properties of starch and gluten |
| Autor: | Viollaz, P.E.; Rovedo, C.O. |
| Ciudad: | Exeter |
| Filiación: | Fac. de Cie. Exact. y Nat. (UBA), Depto. Industrias, Cd. Univ., 1428, Buenos Aires, Argentina Dept. of Biol. and Agric. Eng., University of California, Davis, CA 95616, United States |
| Palabras clave: | Adsorption isotherms; Drying; Moisture; Sorption; Starch; Thermal effects; Thermodynamic properties; Isosteric heat; Food processing; Solanum tuberosum |
| Año: | 1999 |
| Volumen: | 40 |
| Número: | 4 |
| Página de inicio: | 287 |
| Página de fin: | 292 |
| DOI: | http://dx.doi.org/10.1016/S0260-8774(99)00066-7 |
| Título revista: | Journal of Food Engineering |
| Título revista abreviado: | J Food Eng |
| ISSN: | 02608774 |
| CODEN: | JFOED |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02608774_v40_n4_p287_Viollaz |
Referencias:
- Chirife, J., A survey of existing sorption data (1983) In Physical Properties of Foods, pp. 55-64. , London and New York: Applied Science Publishers
- Jong, G.I.W., Berg, C., Kokelaar, A.J., De van den water sorption behaviour of original and defatted wheat gluten (1996) International Journal of Food Science and Technology, 31, pp. 519-526
- Krishna, R., A unified theory of separation processes based on irreversible thermodynamics (1987) Chemical Engineering Communications, 59, pp. 33-64
- Maroulis, Z.B., Tsami, E., Marino-Kouris, D., Saravacos, G.D., Application of the GAB model to the moisture sorption isotherms for dried fruits (1988) Journal of Food Engineering, 7, pp. 63-78
- Rizvi, S.S.H., Benado, A.L., Thermodynamic properties of dehydrated foods (1984) Food Technology, 8392
- Schär, W., Ruëgg, M., The evaluation of GAB constants from water sorption data (1985) Lebbensmittel Wiss und Technology, 18, pp. 225-229
- Van Den Berg, C., (1981) Vapor Sorption Equilibria and Other Water-starch Interactions: A Physico-chemical Approach, , PhD Dissertation, Agricultural University Wageningen, The Netherlands
- Van Den Berg, C., Bruin, S., Water activity and its estimation in food systems: Theoretical aspects (1978) Second International Symposium on Properties of Water in Relation to Food Quality and Stability, , Isopow-II, Osaka, Japan
Citas:
---------- APA ----------
Viollaz, P.E. & Rovedo, C.O. (1999) . Equilibrium sorption isotherms and thermodynamic properties of starch and gluten. Journal of Food Engineering, 40(4), 287-292.http://dx.doi.org/10.1016/S0260-8774(99)00066-7
---------- CHICAGO ----------
Viollaz, P.E., Rovedo, C.O. "Equilibrium sorption isotherms and thermodynamic properties of starch and gluten" . Journal of Food Engineering 40, no. 4 (1999) : 287-292.http://dx.doi.org/10.1016/S0260-8774(99)00066-7
---------- MLA ----------
Viollaz, P.E., Rovedo, C.O. "Equilibrium sorption isotherms and thermodynamic properties of starch and gluten" . Journal of Food Engineering, vol. 40, no. 4, 1999, pp. 287-292.http://dx.doi.org/10.1016/S0260-8774(99)00066-7
---------- VANCOUVER ----------
Viollaz, P.E., Rovedo, C.O. Equilibrium sorption isotherms and thermodynamic properties of starch and gluten. J Food Eng. 1999;40(4):287-292.http://dx.doi.org/10.1016/S0260-8774(99)00066-7
