Dependence of Coating Thickness on Viscosity （涂层厚度依赖粘度）.pdf

JFS: Food Engineering and Physical Properties Dependence of Coating Thickness on Viscosity of Coating Solution Applied to Fruits and Vegetables by Dipping Method L. CISNEROS-ZEVALLOS AND J.M. KROCHTA ABSTRACT: Hydroxypropyl methylcellulose solutions were used as coating systems in this study and solution concen- trations, viscosity, densities, and surface tensions were characterized. Fuji apples were coated by dipping and stored 4 d at room temperature, after which the internal oxygen and carbon dioxide were measured. Results indicated that coating thickness varied with viscosity, concentration, density, and draining time of the biopolymer solution. Coating thickness relates to the square root of viscosity and the inverse square root of draining time, which agrees with the theoretical approach for flat plate dip-coating in low-capillary-number Newtonian liquids. These results indicate the possibility of controlling coating thickness and internal gas composition based on coating solution properties. Keywords: coating thickness, viscosity, fruits, vegetables, modified atmosphere s e i Introduction Eq. 1, proposed by Landau and Levich (1942), is used in the case t r e HE USE OF BIOPOLYMER COATINGS TO MODIFY INTERNAL ATMO - w