COMPARATIVE EVALUATION OF DIFFERENTLY PROCESSED WHOLE EGG POWDER

ABSTRACT
Egg is a nutrient dense food. The cylical egg glut characterized by egg spoilage, quality deterioration and wastage imparts negatively on poultry farmers. Powdered dried egg provides a convient alternative to this problem. The focus of this study was to co mpare and evaluate differently processed whole eggs into powder farm. Two experiments were conducted to evaluate the potential of whole egg powders made from different processing methods. The first compared the yield, proximate composition, microbiological load, functional properties and organoleptic attributes of fried egg and cake from differently processed (Spray dried – commercial, Freeze dried and Dehydrated) whole egg powders. The second assessed the effect of egg age on the proximate composition, microbiological load, functional properties and organoleptic attributes of cookies and cake made from dehydrated whole egg powder. The treatments in experiment one were the Spray Dried, Freeze Dried and Dehydrator Dried Whole Egg Powders represented as SDWEP, FDWEP and DDWEP respectively. Thirty five eggs each were used to produce the FDWEP and DDWEP while the SDWEP was obtained from United State of America. The Experimental design was a completely randomized design. Powder percentage yield of 1000g raw eggs (26.7%) and crude protein (52.78%) was highest (P<0.05) from SDWEP. Salmonella spp observed in raw eggs was destroyed by heat from the processing methods in the whole egg powders. The microbial load was within the 2cfu/g acceptable limits. Functional properties were generally significantly (P<0.05) higher for raw eggs than the whole egg powders, however with no significant (P< 0.05) differences for foaming capacity, foaming stability, emulsifying activity, swelling capacity and bulk density. Fried eggs from raw eggs generally had the highest (P<0.05) organoleptic rating but did not differ from SDWEP, FDWEP for texture and taste, SDWEP and DDWEP for flavour, SDWEP and DDWEP for general acceptability. All whole egg powders compared equally for all indices. Cake colour differed significantly (P<0.05) with Raw, SDWEP and DDWEP rating equally (5.50, 4.40, 4.30 respectively). In experiment two, treatment (weeks 1, 2, 3, 4) had a significant (P<0.05) effect on the crude protein indices of raw eggs with a decline from 50.96 to 42.91% as the eggs aged. Microbial load were within permissible limits. Salmonella spp and E. coli were absent. Foaming capacity declined (37.66-28.22%) with age but was only significant at the 4^{t h} week. Emulsifying capacity, water absorption, water and oil retention capacity with values of 29.85%, 0.86g, 0.52g and 0.52g respectively were best (P<0.05) at the second week. The crude protein and ether extract of the whole egg powder declined from 50.96-42.91% and 5.01-3.87% respectively as eggs aged from one to four weeks. The Microbial load was within permissible limits. Foaming capacity (30.41%), emulsifying capacity (29.41%), swelling capacity (118.74%), water and oil absorption (0.29, 0.29%) were best (P<0.05) at weeks 2, 1 and 3 respectively. Cookies and cakes produced from whole egg powders of one to four weeks of age were generally accepted without specific preference. This study concludes that whole egg powders produced by spray, freeze or dehydrator methods are generally accepted and serve as good alternatives to fresh eggs in addition to their use in the confectionary industry not compromising the final product quality. Dehydrator dried whole egg powder from 3 week old eggs may also be safely used in the confectionary industry without health or product quality disadvantages.