Studies on some engineering properties of dried egg powder reference to its bulk handling

Abstract

Abstract This study investigated some physicochemical and engineering properties of dried egg powder concerning to its bulk handling with the view to promote its usage. The egg was deshelled to have whole egg, egg white and yolk; oven-dried in convective air at 60 °C (± 1 °C), milled and screened with a sieve size with a mesh size of 500 µm. The physicochemical and engineering properties analyses were carried out using standard procedures. The moisture contents ranged from 2.64 to 2.69%, loose and packed bulk densities ranged between 0.45 g/ml and 0.66g/ml (loose), 0.57 g/ml and 0.71g/ml, (packed). The least gelation concentration (LGC) of egg white and whole egg powder occurred at 10%, and, 12% respectively with egg yolk having poor LGC. The density ratio of egg white, whole egg and egg yolk powder were 92%, 76% and 77%, respectively. Egg white, whole egg and egg yolk powder samples had 7.80, 23.43 and 22.12% porosity, respectively The foaming stability of egg white, whole egg and egg yolk powder are 25.05, 28.41 and 26.01, respectively Similarly, the Carr index and Hausner ratio of dried egg white, whole egg and egg yolk powder are 24.48, 7.29 and 22.80; 1.18, 1.35 and 1.32, respectively indicating the egg powder samples were free-flowing. The emulsifying activity index of egg white, whole egg and dried egg powder are 3.84, 1.78 and 5.96, respectively while emulsifying stability index of the same samples are 503.30, 57.83 and 37.87, respectively. The colour intensity determined for egg white, whole egg and egg yolk powder was 61.75, 41,15 and 52.45, respectively Also, the thermal properties of the samples measured using differential scanning calorimeter ranged between 79.3 ⁰C - 92.8 ⁰C, 106.4 ⁰C - 121.2 ⁰C, 106.2 ⁰C - 122.8 ⁰C, 56.75 J/g - 278.6 J/g, 21.4 ⁰C - 94.743.5 ⁰C, 10.95 J/(gK) - 20.28 J/(gK), 0.50 w/m⁰C - 0.70 5 w/m⁰C, and 0.090 m2/s - 0.094 m2/s for onset temperature, peak temperature, end temperature, enthalpy, temperature range, specific heat capacity, thermal conductivity and thermal diffusivity respectively. The study therefore, provides engineering data about process design, control and bulk handling to extend the usage of dried egg powder samples in food process industries.