Thesis Abstract

Abstract
The storage of eggs is a critical factor that can significantly impact their quality and organoleptic properties. This study was conducted to investigate the effect of different storage methods on the quality and organoleptic properties of brown eggs from domestic fowl. Freshly laid brown eggs were collected and divided into four groups for storage under different conditions refrigeration at 4°C, room temperature (about 25°C), cold storage at 15°C, and vacuum packaging followed by refrigeration. The eggs were stored for a period of four weeks, and their quality parameters were evaluated weekly. The results showed that the storage method had a significant influence on the quality of brown eggs. Eggs stored in refrigeration at 4°C maintained their quality best throughout the four-week storage period, with minimal changes in weight loss, albumen height, yolk index, and Haugh unit values. Room temperature storage resulted in a rapid decline in quality, with a notable decrease in Haugh unit values and an increase in weight loss. Cold storage at 15°C also exhibited a decline in quality, albeit at a slower rate compared to room temperature storage. Vacuum packaging followed by refrigeration proved to be an effective method in maintaining egg quality, showing results comparable to refrigeration alone. In terms of organoleptic properties, sensory evaluation revealed that eggs stored in refrigeration at 4°C and vacuum packaging followed by refrigeration retained their freshness and flavor better than those stored at room temperature and cold storage. The yolk color of eggs stored in refrigeration was also more vibrant compared to the other storage methods, indicating better preservation of carotenoids. Overall, the findings of this study demonstrate that storage methods significantly impact the quality and organoleptic properties of brown eggs from domestic fowl. Refrigeration at 4°C emerged as the most effective storage method in maintaining egg quality over a four-week period, followed by vacuum packaging combined with refrigeration. These results highlight the importance of proper storage practices in preserving the quality and sensory attributes of eggs, which can ultimately influence consumer satisfaction and market value.

Thesis Overview

1.1 BACKGROUND OF THE STUDY

Eggs (like other agricultural products) are perishable and consequently require proper and effective storage to reduce post harvest losses. Eggs are delicacies relished in both rural and urban areas with chicken eggs being the most popularly produced and consumed (Fasina et al., 2012). Eggs are highly palatable and can be prepared or utilized in a number of ways. Eggs are perfectly balanced foods containing proteins, vitamins (except vitamin C ) and minerals required for good health by both the young and old (NECC, 2014). According to FAO (2003), eggs are consumed primarily as protein sources and are considered as complete proteins because they contain all nine essential amino acids making them an excellent source of high quality protein (93.7%).

Eggs come in a variety of colours (white, brown, tinted, white to tinted, blue) depending on the breed and variety of the bird (Doug et al., 2002). In Akwaibom state Nigeria, brown eggs are mostly produced and consumed. Consumers of egg pay more attention to egg shell colour though there is little or no direct relationship between shell color and nutritional characteristics/content of the egg (Scotts and Silversides, 2000).
Eggs are collected and stored prior to period of consumption which could range from days to months depending on the method of storage. Common storage methods include Wet sand storage, storage in plastic trays or open bowls under room temperature, storage in sawdust, storage in polyethene bags, oiling and cold refrigeration. The latter is least practiced in Nigeria for a number of reasons but mainly due to the poor state of power supply in Nigeria and also due to ignorance as most people who own refrigerators do not think it right to store eggs in the refrigerators. Egg storage influences the rate at which eggs undergo physical and biochemical changes that lead to the reduction in egg quality thus influencing its nutritional composition and acceptability for consumption and other uses(Fasina, 2012; Mohammed, 2011; Okeudo et al, 2005; Raji, 2009; Scotts and Silversides, 2000).

According to Stadelman (1986), egg quality refers to the characteristics of an egg that will affect its acceptability to the consumer. It then becomes necessary to properly store eggs in order to maintain its quality and also to derive maximum utility from consumption of eggs.

1.2 STATEMENT OF THE PROBLEM

Currently, poultry production is fast becoming intensive in Nigeria and has become a dependable source of income for many farmers. With increase in poultry production and harvest of poultry products, we are faced with the pressing need to preserve poultry products- in this case- eggs to prevent or reduce post harvest losses due to spoilage and wastage.

1.3 OBJECTIVES OF THE STUDY

The objectives of the study are:

To examine the effect of storage methods on egg quality and organoleptic properties of brown egg type of domestic fowl in Akwa ibom state.
To examine the microbial load of eggs stored under different conditions.

JUSTIFICATION FOR THE STUDY
There is marked increase in poultry production in Nigeria as a result of the steady and substantial income actualized from its production particularly in layer production as eggs are gotten almost every day under proper management. This increase in productivity heralds the pressing need to effectively store and preserve poultry produce (particularly eggs as related to the study) in the hands of the producers as well as the consumers.

Eggs spoil in homes due to improper storage leading to deterioration in egg quality both physically and chemically (Obi and Igbokwe, 2011). Observed changes include watery albumen, enlargement and flattening of egg yolk and air cells and absorption of off-flavours and odours (FAO, 2003; Mohammed, 2011; Scotts and Silversides, 2000).This study aims at identifying a suitable storage method that will significantly reduce the rate at which biological and physico-chemical changes occur within the egg.