Comparative Evaluation of Cholesterol Content and Storage Quality of Chicken and Quail Eggs

Abstract

In recent times, the consumption of quail egg has become a food fad, with little knowledgeable input, owing to the claim that it is lower in cholesterol than chicken egg, hence, there is need for more scientific basis to certify the preferred consumption of quail egg over chicken egg as a food fad which should be encouraged or a food fallacy that needs to be corrected. This study was therefore designed to determine the storage quality and cholesterol content of chicken and quail eggs during the two commonly used storage methods. Eggs of 53 weeks old chicken (ISA-Brown) and 9 weeks old quail (Japanese Breed) were analyzed for pH, microbial count and cholesterol content on the day of lay and weekly during cold (4°C) and room temperature (27°C) storage for 5 weeks using appropriate analytical kits. Data were analyzed using means, standard deviation and ANOVA. The pH of chicken egg albumin (CA) and chicken egg yolk (CY) at the day of lay (R0) were 7.48 and 5.65 respectively and these significantly increased to 12.31(CA); 9.56 (CY) and 8.94 (CA); 6.85(CY) at 5 weeks’ room temperature (R5) and cold (C5) storage respectively. The pH of quail egg albumin (QA) significantly increased from 8.67 at R0 to 12.99 at R5 and 9.83 at C5 while that of quail egg yolk (QY) increased from 5.92 at R0 to 10.00(R5) and 6.86(C5). Both eggs were sterile throughout the experimentation period. At R0, cholesterol content (mg/g) of CA, CY, QA and QY were 22.67, 33.67, 34.33 and 46.83 respectively; at R5 these significantly increased to 62.67(CA), 96.00(CY), 49.33(QA), 68.67(QY) and at C5 the values were 54.17(CA), 78.17(CY), 51.17(QA) and 68.00(QY). The reduced quality of the eggs with storage was not as a result of microbial invasion but of deteriorative reactions within the eggs. Though the cholesterol content of chicken egg was lower than that of quail egg at the day of lay it was significantly higher in chicken egg by the end of the 5 weeks storage period. However, fractionation of the cholesterol into the different types is recommended for a better understanding of the nutritional significance.