Effects of clove oil released in active packages on shelf life extension of egg during storage under refrigerator

Abstract

It is very important to refrigerate eggs after reaching home to prevent illness from bacteria. However, psychrophilic bacteria can grow at refrigerator temperatures which may cause egg spoilage. Also, some bacteria on the egg are harmful to human health. The objective of the study was to investigate the effect of clove oil (20 40 and 60 µg g^-1) release from an adsorbent material on the shelf life extension of eggs stored at 4 ± 1 °C for 45 days. A control, without clove oil, was studied in the same way. Total psychrotrophic bacteria, weight, yolk index, and the Haugh unit during storage were investigated based on normal standards. In addition sensory evaluation of a treated boiled egg and control were also conducted using the 9 – Point Hedonic Scale. The results showed that there were no psychrotrophic bacteria in eggs kept in clove oil at 40 µg g^-1 for 45 days while in the control eggs this was well above the standard. The flavor and taste of the boiled egg after storage with clove oil at 40 µg g^-1 were not different from the control (p>0.05). The physiochemical properties of the eggs (weight loss, yolk index, Haugh unit) during storage were found to meet the standard quality used for eggs. The change in the weight loss of the egg was found to be only 3.0 %. The yolk index of the treated egg was 0.41 (higher than the control) (p<0.05) while the Haugh unit was not different from the control (P>0.05). The major constituent identified from the eggshell when kept in clove oil was eugenol. This finding indicates that the use of clove oil gives a longer shelf life and comparable egg quality compared with untreated eggs kept in a refrigerator only.