Analysis of mass transfer parameters (changes in mass flux, diffusion coefficient and mass transfer coefficient) during baking of cookies

作     者：Demirkol, E Erdogdu, F Palazoglu, TK 

作者机构：Mersin Univ Dept Food Engn TR-33343 Mersin Turkey 

出 版 物：《JOURNAL OF FOOD ENGINEERING》 (食品工程杂志)

年 卷 期：2006年第72卷第4期

页      面：364-371页

核心收录：

学科分类：0832[工学-食品科学与工程（可授工学、农学学位）] 0817[工学-化学工程与技术] 08[工学] 

基　　金：TÜBİTAK, (TOGTAG 3201) Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÜBITAK 

主　　题：mass flux mass transfer coefficient diffusion coefficient baking 

摘      要：Increasing trade of ready to eat foods such as cookies highlights an interest in quality defects (cracking, checking due to nonhomogenous moisture distribution) during baking. The most important parameter resulting in adverse quality changes is nonhomogenous moisture distribution due to diffusion and external convective mass transfer coefficient. To control and optimize a baking process for quality purposes, actual values of mass transfer parameters should be known. Infinite external convective mass transfer coefficient and constant diffusion coefficient approaches are numerously applied in the literature. However, in natural convection cases, mass transfer coefficient value may not be infinite. In addition, the diffusion coefficient may be time and/or temperature dependent. To compare the finite and infinite external mass transfer and diffusion coefficient approaches, in this study, baking cookies was taken as an experimental case. For this purpose, moisture changes for cookies were estimated based on weight changes and initial moisture contents during baking at 190, 200 and 210 degrees C. Then, infinite external convective mass transfer coefficient and constant diffusion coefficient value approaches were applied and compared to finite-variable external convective mass transfer coefficient and variable diffusion coefficient value approaches. These values were found to vary during baking, and they were a function of internal cookie temperature changes. It was also concluded that the variation in these values should be determined for effective mass transfer and optimization models. (c) 2005 Elsevier Ltd. All rights reserved.