Effects of black seed oil and rosemary extract coating on egg shelf life at refrigerator temperature

Abstract

Eggs are highly perishable due to high moisture content and nutrients. This study aimed to investigate the effect of coating with black seed oil and rosemary extract on egg physical, chemical, functional and microbial characteristics. For this purpose, 300 eggs consisted of control group, eggs coated with black seed oil, and samples coated with black seed oil and 1, 2, and 3% rosemary extract were prepared. Throughout the six weeks of storage at 4 °C, thickness, weight loss, Haugh unit, yolk index, pH, amount of egg white foam production and microbial features were investigated. The weight loss in the control group was 6.64 and 4.80 g in the control group and the treatment with 3% rosemary extract, respectively. In the control group, Haugh unit was decreased from about 75 on the first day to 31.38 after six weeks storage. Haugh unit in the egg group coated with 3% rosemary extract was 41.76. The microbial load of shell after six weeks of storage in the control sample was 4.59 log CFU/g, and in the samples coated with black seed oil alone and in the presence of 1%, 2% and 3% rosemary extract were 4.32 and 3.99, 3.27, 2.30 log CFU/g, respectively. Due to the bactericidal effect of coating components, egg-shell microbial load was decreased. The coating was able to increase the shelf life up to six weeks.

Keywords

• egg
• coating
• black seed oil
• rosemary extract