FST 202 Evaluation of egg quality

October 4, 2017 | Author: Nur Fadhilah | Category: Yolk, Egg, Egg White, Odor, Chicken
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Food quality control...









: 2013698078 : AS 1165A2 : 29TH JULY 2015 : MADAM MARDIANA BT AHAMAD

INTRODUCTION Hen’s egg is a common egg that used nowadays and most of the hen’s egg on the market has been classified according to quality and size under USDA standards. The eggs must be stored in clean, dry storage with new and clean packaging material. For tropic environment, the eggs may quickly deteriorate, therefore refrigeration is necessary for the successful storage for consumer’s use. Besides that, grading of the eggs is also necessary to protect the consumer from undue risk. During the grading stage, all the eggs are received, weighed, washed, candled, weighed and packed into a container with the application of inspection in a sanitary environment. The inspection of the eggs is conducted by random candling and grading process in the warehouse or any location storage to ensure that the eggs meet the quality requirements. During, the candling process, the egg pass over a bright candling light which makes the internal content is visible and allowing to detect any internal defects of the egg such as spot, poor quality yolk and air cell size. The average sized egg weighs approximately 57 g. 36% of the weight of fresh whole hen eggs is a portion of the egg yolk with the vitelline membrane. The total solids content of yolk is about 50-52%. The white eggs takes about 60% of the whole hen egg which consist of chalazae, inner thin, outer thick, outer thin albumen with 11-12% of total solids content. The shells of the eggs have rigid yet porous structure which constitute 11 percents of the total egg white and largely consist of calcium carbonate, magnesium carbonate, calcium phosphate and organic matters. The changes in egg with deterioration takes place physically and chemically due to temperature, humidity, air movement, and storage time factor which cause adverse effect on the interior quality. If these factors are not carefully control the loss moisture in egg may occur causing the loss weight of the egg. Internal quality of the egg yolk at the sided position and discoloured indicates that the egg already aged. Off flavour of the egg is commonly due to the slow chemical breakdown while the rotting egg is caused by the microorganisms.


RESULTS Table 3.1 Parameter Exterior Cleanliness of shell Presence of brown spot Surface of egg shell

Brand A

Brand X

Clean Absent Smooth

Less clean Present Less smooth

Interior Depth of air cell (cm) Thickness of egg white Height of the yolk (cm) Diameter of the yolk (cm) Colour of the yolk Position of the yolk Chalazae Aroma

1.0 cm Thick 0.2 cm 5 cm Orange Center Present Normal

1.2 cm Thin 0.1 cm 5.5 cm Yellow Off center Absent Unpleasant

DISCUSSIONS The evaluation of the egg quality exterior and interior are important to fulfil the consumer preferences for better quality egg as the quality influence on the acceptance or rejection of the products by the consumer. This experiment is conducted to determine the quality of eggs with different brands, which are Brand A and Brand X. According to USDA standards the exterior quality of an egg is judged on the basis of texture, colour, shape and soundness. However, in this practical, the eggs are evaluated externally only on its cleanliness, the presence of brown spot and surface of the egg shell. Brand A egg is cleaner and has smoother surface of the egg shell compared to Brand X. Brand X has small patches of chicken’s faeces on the shell, shows that the egg does not thoroughly cleaned during the egg grading process. Besides, there is also the presence of the brown spots on Brand X egg. Those spots are similar to calcium deposits unless the spots appear smaller. The speckles may be presented pigmented due to the poor nutrition cause by the excess consumption of calcium in the hen’s diet. The stress or disturbance during calcification process may also one of the cause for the presence of the brown or speckles spot. Good interior egg quality is essential to consumer especially for those people who use eggs in common baking and cooking process. As the egg ages, the egg air cell becomes wider

that can cause the egg to deteriorate which shown that Brand X has the slightly wider air cell and aged with 1.2 cm of air cell compared to Brand A with 1.0 cm. The egg white is judged on the basis of thickness and the firmness. From the result, it shows that Brand A egg white is thicker than Brand X. The thin and watery egg white may due to the high temperature of the egg storage, loss of carbon dioxide from egg during storage and it can occasionally be a reaction to certain vaccinations. The yolk of the Brand A is stand firm on shape with 0.2 cm height and 5 cm of diameter while Brand X yolk seem to be more flattened with much thin and watery egg white. The thick egg white presence on the Brand A permits limited yolk movement while thin albumen permits greater movement of the egg yolk which contribute to low graded egg. The water passes from the white to the yolk increasing the size and fluid content of the yolk, thus decreasing the yolk solids. The colour of the egg yolk of Brand A is orange while Brand X is yellow which are both comes from the substances called carotenoids. However, the colour of the yolk does not affect the nutritional value off the egg. The hen’s feed that is low in carotenoids such as such as white corn may result to paler egg yolk. In general, the better centre of the egg yolk with the normal aroma indicates the Brand A is fresh compared to off centre yolk and unpleasant aroma of the Brand X egg. Chalaeza is the ropey strands off egg white which anchor the yolk at the center of the thick white. The Brand A egg’s chalazae is more noticeable compared to the Brand X. The fresh egg always comes with the prominent chalazae.

CONCLUSIONS In a nutshell, Brand A is fresher than Brand X egg as it fulfils the customer preferences for a better quality eggs. Brand A has the high quality external and internal quality of egg. It has cleaner, smooth surface of egg shell without the present of the brown spot. Besides, it also has thick egg white that holds firmly on the center of the orange egg yolk with normal aroma and the present of chalazae compared to Brand X with the opposite quality.


1. How is the depth of the air cell and deterioration of the egg related? The depth of the air cell is a rough indication of the age of egg and related to its quality. The high grade egg has shallower air cells. The air cells in eggs take in air according to the age. The air cells will become larger over time and cause further deterioration.

REFERENCES 1. Severs, L. (2012, May 23). Egg Inspection. Retrieved July 9, 2015, from http://agr.wa.gov/FoodAnimal/Eggs/EggInspection.aspx 2. Common Egg Quality Problems, (2015, April 20). Retrieved July 13, 2015, from http://www.backyardchickens.com/a/common-egg-quality-problems 3. Anton, M. (2007). Composition and Structure of Hen Egg Yolk. Bioactive Egg Compounds, 1-6. 4. Haugh R R 1937 the Haugh Unit For Measuring Egg Quality; US Egg and Poultry Magazine, 43: 552-555 .

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