Experimental and Mathematical Description of Sorption Isotherms and Thermodynamic Properties of Salted and Dried African Catfish (Clarias gariepinus)

Abstract

Sorption isotherms and thermodynamic properties of brine salted and dried (BSD) and dry salted and dried (DSD) African catfish in the water activity (aw) range (0.33-0.85) was determined and compared at 25, 30 and 40C using the static gravimetric method of saturated solutions. Five sorption models: GAB (Guggenheim-Anderson-de Boer), BET (Brunauer-Emmett-Teller), Kuhn, Adam and Shove and Henderson were fitted with the experimental sorption data obtained. Curves for both samples followed the type III BET classification scheme. Equilibrium moisture content (EMC) decreased with increase in temperature at low and intermediate aw (0.33-0.65) while there was an inversion of this trend at higher aw (0.75-0.85) with DSD samples having higher values at the same experimental conditions. GAB model predicted best with the monolayer values varying between 0.047 to 0.054 kg/kg db for BSD samples and 0.047 to 0.052 kg/kg db for DSD samples. Salting technique affected significantly the properties investigated

Predicting the Nutritional and Rancidity Properties of Dehydrated Catfish (Clarias gariepinus ) Using Response Surface Methodology

“…The moisture contents ranged from 5.47~8.41% (Table 1) from the initial value of 76.12% and were generally lower than the value (15.62%) obtained by Chukwu and Shaba (12) in an electric oven with dried catfish at 120°C without prior brining. This shows that the brining operation in the present study enhanced dehydration and lower moisture content as a result of an osmotic effect of the brine on moisture drip from the fish muscle, similar to the findings of Sobukola et al (23). This is evidence in the significance ( P <0.05) of the brining parameters (brining time, interaction of brine concentration and brining time, and quadratic term of brine concentration) on the moisture content (Table 3).…”

Chemical Properties and Moisture Sorption Isotherm of Smoke- Dried Catfish (Clarias gariepinus) and Mackerel (Trachurus trachurus) Produced with a Modified Smoking Kiln: Application of Four Models to Sorption on Data

“…hence the higher will be the equilibrium moisture content [15,16]. Since dietary items high in protein have been reported to exhibit the type III morphologies, the type III isotherm displayed by smoke dried catfish and mackerel is as expected [17,18]. According to Fennema, Onimawo and Akubor [6,3], proteins have many sorption sites where each water molecule makes hydrogen bonds with up to four nearby water molecules.…”