Effects of Fat Content and Packaging Materials on the Functional Properties and Storage Stability of Dika Nut (<i>Irvingia gabonensis</i>) Flour

Abstract

This study evaluated the influence of fat content and choice of packaging material on the functional properties and shelf stability of dika nut flour. Dika nut flour was partially defatted to achieve two levels of fat content (12 and 9% fat). The partially defatted and full fat (67%) dika nut flour samples were packaged in high and low density polyethylene films. The flour samples were stored at ambient condition (26 + 2°C, 78 + 2% RH) for twelve weeks and changes in chemical composition, functional properties and microbiological qualities of the flour samples were determined using standard methods. The results obtained showed significant (p>0.05) increases in moisture (4.02 – 11.20%), free fatty acid (0.33 – 0.94%), peroxide value (2.30 – 11.50meq/kg), bulk density (0.26 – 0.71g/cm3), viscosity (12.53 – 48.90cP), total bacteria count (2.10 x 102 – 6.5 x 103cfu/g) and mould count (2.30 x 102 – 6.10 x 103cfu/g) of dika nut flour samples; while dispersibility (85.67 – 74.80%), water absorption capacity (25.50 – 20.65g/g) and oil  absorption capacity (5.07 – 3.60g/g) decreased significantly (p> 0.05) during storage. Models of regression equation (0.801 < R2 < 0.992) used to estimate the shelf life gave 34 weeks for dika nut flour (12% fat) and 33 weeks for dika nut flour (9% fat) packaged in high density polyethylene film while those packaged in low density polyethylene films gave shorter estimated shelf life of 15 weeks for full fat dika nut flour. The study showed that partial defatting could be used to improve the functional properties of dika nut flour for soup preparation as well as its storage stability.

Keywords: Dika nut flour, functional properties, defatting, packaging materials, shelf life.