Effects of Selected Additives’ Concentrations on Shelf life of the Ready-to-Eat Hard-Boiled Chicken Eggs

Lee, Kae Li (2024) Effects of Selected Additives’ Concentrations on Shelf life of the Ready-to-Eat Hard-Boiled Chicken Eggs. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Egg is a common source of microbiological contamination due to high moisture content and water activity. The objectives of the study are i) to develop ready-to-eat hard-boiled chicken eggs with selected additives’ concentration for a shelf life of 30 days, ii) to determine the physicochemical, microbiological, sensory properties, and proximate composition of preserved ready-to-eat hard-boiled chicken eggs, and iii) to investigate the effects of selected additives’ concentration on shelf life of the preserved ready-to-eat hard-boiled chicken eggs stored at 4°C. Three treatments (treatment 1: 6 ppm nisin + 0.5% citric acid, treatment 2: 6 ppm nisin + 1% citric acid + 0.14% sodium carbonate, and treatment 3: 5 ppm nisin + 1% citric acid + 0.14% sodium carbonate) were developed and compare with the control sample (no additives added). Physicochemical analysis (water activity, color, texture, weight loss, pH, ammonia), proximate analysis, microbiological analysis (total plate count, yeast and mold, salmonella, and listeria) were carried out to determine the shelf life of RTE hard-boiled chicken eggs. Experiments were carried out at two storage temperatures, stored at 4°C for a total of 30 days, and at 25°C for 6 days. The microbial count for all control and samples stored at 4°C fell within the acceptable range, however, treatment 2 and 3 samples stored at 25°C fell out of the acceptable range on day-6 storage. There was a significant difference (p < 0.05) between the whiteness, moisture content, water activity, pH, ammonia level, and percentage weight loss between the control and hard-boiled chicken eggs samples. There was no significant difference (p > 0.05) between the control and hard-boiled chicken eggs samples in terms of the springiness and chewiness in terms of texture profile analysis and color analysis. Both treatment 2 and 3 samples showed no significant difference for all the attributes (p > 0.05) in the quantitative descriptive analysis (QDA) except egg flavor of treatment 2 on day-30 storage (p < 0.05). In conclusion, treatment 2 and 3 samples were selected as the best-preserved ready-to-eat (RTE) hard-boiled chicken eggs in this project.