Heat and water transfer during the dehydration of herring fillets

Abstract

The. rate of drying of herring fillets in an over-draught dryer was very sensitive to temperature, but practically unaffected by normal ranges of wet-bulb depression and air velocity. Fatty herrings took longer to dry than lean ones and considerable fat oxidation occurred during the process. Variation of thickness within the range usually encountered was of some importance.The storage life of fillets, which depends very much on taste, was limited chiefly by ( I ) the oxidation of the fat, which could be prevented by packing in an inert gas, and (2) the development of moulds, which occurred unless the moisture content was below about 16%. It was found from a determination of equilibrium moisture contents a t a number of relative humidities that this corresponded to about 70-75% R.H. It is considered that if suitably packaged, the best products could be kept in condition acceptable to some native races in tropical regions for several months under the prevailing climatic conditions.

Salting and Drying Fish. 3. Diffusion of Water

“…Del Campo et al (1956) found that fatty herrings took longer to dry than lean ones, and that considerable fat oxidation occurred during the process. Finally, Lintoh et al (1945), studying the drying of heavily-salted cod, reported that the optimum drying conditions for this product were: air velocity of 100 to 125 cm/set, air temperature of 26°C and relative humidity of 45 to 55%.…”