Moisture Sorption Isotherm, Proximate Composition, Lipid Oxidative Stability and Sensory Characteristics of Sun Dried Kilishi in Storage

Abstract

The study investigated the relationship between moisture sorption isotherm and some quality parameters of sun-dried kilishi in storage using various methods of analysis and experimentation. The Guggenheim, Anderson, de Boer (GAB) model was used to determine sorption isotherm characteristics, thiobarbituric acid reactive substances (TBARS) assay was used to measure malondialdehyde (MDA) levels while the procedures of Association of Official Analytical Chemists and 9- point hedonic scale were used to evaluate proximate composition and sensory qualities respectively. The results of sorption indicated that the product had water activity and monolayer moisture of 0.39 and 15.82 (g H20/g Solid) respectively while proximate composition of sundried kilishi before and after storage at 45 0C showed that the protein content of this product after 35 days of storage was significantly higher (p<0.05) than before storage. The study also revealed a decrease in fat content in storage, as malondialdehyde level increases from 0.223 to 0.341. Sensory characteristics were also affected in storage. Aroma, flavour, juiciness and overall acceptability significantly decreased (p<0.05) after storage at 45 0C for 35 days as compared to the sensory status of this product before storage. In conclusion, moisture sorption and environmental conditions need proper control to keep sun dried kilishi stable on shelf.