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USE OF TIME‐TEMPERATURE DATA DURING FLUIDIZED BED FREEZING TO DETERMINE FROZEN FOOD PROPERTIES
Author(s) -
MARIN M.,
RIOS G. M.,
GIBERT H.
Publication year - 1985
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/j.1745-4530.1985.tb00309.x
Subject(s) - thermal conductivity , fluidized bed , latent heat , thermodynamics , enthalpy , inert , chemistry , process engineering , materials science , chromatography , physics , organic chemistry , engineering
Most of the methods proposed in literature for freezing time calculation require the previous knowledge of the enthalpy change and thermal conductivity of frozen materials. Ordinarily these properties are not easy to obtain, and often need a special approach depending on the process under consideration. This paper deals with a new and simple method that affords an estimation for Fluidized Bed Freezing of small food pieces (20‐40 mm) immersed in a cold fluidized bed of fine inert particles. Based upon Plank equation and temperature‐time recordings, the method more particularly yields the latent heat to be removed for bringing the product below the freezing poatt and the thermal conductivity of the matter in this final state. The associated percentage of water actually frozen during operation may be also determined. With the help of this technique properties have been determined for various fruits and vegetables (banana, carrot, potato, turnip and cucumber). The values that have been found agree well with literature data: latent heats correspond to the latent heat required to freeze 80% of the water in the products, and thermal conductivities lie between 1 and 2 W/m °C. Helpful correlations for Fluidized Bed Freezing time calculation are proposed that simply relate these properties to the total water content of materials.