Bibiana Dooshima Igbabul
University of Agriculture Makurdi, Nigeria
Title: Moisture sorption thermodynamics properties and shelf life stability of salted tropical freshwater catfish
Biography
Biography: Bibiana Dooshima Igbabul
Abstract
The catfish (Heterobranchus bidorsalis) is among the most commercially important freshwater fish species in Nigeria. It is preferred due to low price, its fleshiness, taste and ease of processing. The fish is however highly perishable under tropical ambient conditions. Salting and drying which are widely used processing and preservation methods in Nigeria are used in this study. The effect of salting (0, 5 and 10%) and temperatures (25, 30, 40 and 50oC) on sorption isotherms of catfish were investigated using gravimetric methods. The equilibrium moisture content data were used in the analysis of sorption, applying Clausius-Clapeyron and the Guggenheim-Anderson-de Boer (GAB) equations. The sorption data was applied to 2 packaging materials stored at relative humidity of 80 and 85% and temperatures of 30oC and 40oC. The monolayer moisture contents (2.830-4.958 g H2O/100 g solid) and surface areas of sorption (99.43–172.72 g H2O/100 g solid) decreased with increase in temperature and salt content and were higher for desorption than adsorption mode. The net isosteric heats of sorption (22.5–3.9 KJ/mol within 1.0–12.0 g H2O/100 g solid) also decreased with increase in salt content in adsorption mode but increased in desorption mode. The net entropy of sorption (-45.2 to–8.0J/mol within 1.0 to 12.0 g H2O/100 g solid) increased with salt content in adsorption and was higher than desorption. The storage life of the fish was significantly P<0.05 influenced by relative humidity (RH), water vapor permeability (B) of the packaging films and salting.