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Interactions between water and EVOH food packaging films / Interacciones entre el agua y películas de EVOH para el envasado de alimentos 全文
2000
Aucejo, S. | Catalá, R. | Gavara, R.
The transport of water in four EVOH copolymers commonly used in high barrier food packages was characterized through permeation (continuous flow) and gravimetric experiments at different rela tive humidities and 23 ± 2°C. Water sorption isotherms were fitted with the D'Arcy and Watts' equa tion. From these data, the value of the solubility coefficient (S, as defined by Henry's law) was deter mined and was found constant within a 0.2-0.75 water activity (a w) range. Water uptake at the same a w increased as the EVOH ethylene content decreased. The permeability coefficient (P) for water through EVOH was determined as a function of water activity. The permeability was constant within the range of 0.3-0.75 a w and decreased with EVOH ethylene content. At high relative humidities (a w > 0.75) the value of permeability increased by up to two orders of magnitude. In this range, the higher the ethylene content the lesser the value of P.
显示更多 [+] 显示较少 [-][Water content and water activity in food]
1992
Dufour, D. (Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement, Montpellier (France). SAR, Systemes Agro-Alimentaires et Ruraux)
Water and food quality
1989
Hardman, T.M. (ed.)
Water activity and food
1978
Troller, John A. | Christian, J. H. B.
Water and food quality
1989
Hardman, Thelma M.
Handbook of food isotherms
1982
Iglesias, Héctor A. | Chirife, Jorge
Abstract: A handbook is devoted entirely to water vapor sorption data of foods and food components and includes over1000 isotherms. A mathematical description is provided for over 800 of the isotherms. An introductory section discussesthe equilibrium relation between the moisture content of foods and water activity (related to the relative humidity of the surrounding atmosphere) depicted in the water sorption isotherms of foods; changes affected by water activity (microbial growth, enzymatic reactions, non-enzymatic browning and lipid oxidation, food texture changes) also are discussed. The main recommended uses of the water sorption isotherms are discussed, as well as the influence of food pretreatments, composition, and food species differences. Guidelines are included for the graphical representation of experimental data on water sorption in foods, and on the criteria used for the compilation and representation of the data. (wz).
显示更多 [+] 显示较少 [-][Food water activity: measurement methods]
1992
Gomez Diaz, R. (Cordoba Univ. (Spain). Facultad de Veterinaria)
Se han revisado diversos metodos de determinacion de la actividad del agua. Los metodos pueden dividirse en aquellos que requieren el uso de instrumentos comunes de laboratorio y en aquellos que necesitan para su determinacion aparatos especiales. La principal ventaja de los que necesitan aparatos especiales es que la actividad del agua puede determinarse mas rapidamente
显示更多 [+] 显示较少 [-][Water activity and food stability]
1992
Dufour, D. (Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement, Montpellier (France). SAR, Systemes Agro-Alimentaires et Ruraux)
Water activity measuring instrument for food products
1995
Kittichai Banchong | Sakun Bun-it | Suppharoek Adunprasoetsuk (King Mongkut's Inst. of Technology Ladkrabang, Bangkok (Thailand). Faculty of Agricultural Technology. Dept. of Agro-Industry)
