Storage Stability and Quality Changes of Extruded Whole Wheat Snacks Enriched with Chicken Egg and Its Fractions

Abstract

The aim of the study was to produce and evaluate the storage stability of extruded snacks from chicken egg and whole wheat flour. The whole wheat flour (WWF) and raw whole egg (WE) or raw egg yolk (EY) or raw egg white (EW) were mixed in different proportions (100 % WWF; 85 % WWF and 15 % raw WE; 80 % WWF and 20 % raw WE; 85 % WWF and 15 % raw EY; 80 % WWF and 20 % raw EY; 85 % WWF and 15 % raw EW; 80 % WWF and 20 % raw EW). Extrusion of the samples was done in a twin screw extruder. The extrusion parameters were constant for all the samples. After production, the extrudates were divided into three portions. One portion was used for initial quality evaluation: Moisture content, water activity; microbial quality (total viable count (TVC), mould count (MC), thiobarbituric acid (TBA) value. The second (2nd) and third (3rd) portions were stored at ambient room conditions (25-30°C) and at 37 oC respectively, for 12 weeks and evaluated for quality changes at two weeks interval. Results show that in month 3, the MC were within permissible limits. The moulds identified in samples may have resulted from contaminants during handling after extrusion. The moisture content (6.5 – 9.0 %) of the samples were stable during the period of storage. The water activity of the samples slightly increased with storage time both for samples stored at ambient temperature (0.69 – 0.76) and for those stored at 37 oC (0.61 – 0.74). The TBA Values (0.01 - 0.06 mg Malondialdehyde/ kg sample) were very low and far below the required minimum for rancidity to be detectable throughout the storage period.