Akademik Veri Yönetim Sistemi
JOURNAL OF FOOD PROCESS ENGINEERING, cilt.29, sa.2, ss.188-201, 2006 (SCI-Expanded)
Moisture distribution in baked products at the end of baking is important because it directly affects the product's quality In fact, nonhomogeneous moisture distribution may result in quality defects such as cracking, checking etc. Diffusion inside and convective mass transfer outside the product are important factors affecting the quality. Therefore, accurate values of mass tran. fer parameters should be known for optimization of the baking process to obtain a product of higher quality. For this objective, infinite mass transfer and constant diffusion coefficient simplifying approximations have been applied in the literature numerous times to develop mass transfer models. However, the infinite mass transfer coefficient approximation may not hold true, especially under natural convection conditions. To evaluate the mass tran, fer coefficient, baking experiments were carried out to obtain the moisture content changes of cookies during baking at 190, 200 and 210C under natural and forced convection conditions. Then, mass transfer coefficient was determined using the moisture content difference and the humidity ratio difference as the driving force for mass transfer The results of these two approaches were compared, and the use of humidity ratio difference seemed to be a better approach in terms of reflecting actual process conditions because it is based on the surface changes.