Penentuan Nilai Konduktivitas Panas dan Permeabilitas Uap Air pada Lapisan Kering Daging Sapi Giling Selama Proses Pengeringan Beku

Abstract

Freeze drying has had a gr2at impact upon the the production of dehydrated food because of the superior quality of the product obtained. However, the process is only feasible if the cost of production can be lowered by optimum plant operations. This requires not only a good engineering design and control to minimize the drying time, but also detail knowledge on the transport properties of material to be dried and its characteristic behavior during freeze drying. The objective of this study was to determine thermal conductivity and permeability within the dried layer of minched beef during freeze drying. Effects of freezing rate of freezing process on tthe drying time were not appearred definitely under experimental condition. The drying time was found to be depended mainly on the heater plate and external coldtrap temperature. The drying time decreased with increasing heater plate temperature and decreasing external coldtrap temperature. Effects of freezing rate of the dried layer on thermal conductivity were not appearred definitely under experimental condition. The average of thermal conductivity with in 4.62 - O. 79 em/hour range of freezing rate was assessed to be 0.0563 W/mK. The permeability increased with decreasing freezing rate of freezing process. Water vapor permeability value found in this study was range at 0.0013 - 0.0024 m2/second.