INDEPENDENT TASK
AGRICULTURAL PRODUCT COMMODITIES
Prepared to fulfill the assignments of the Agro-industrial Material Science course Supporting lecturer: Prof. Dr. Ir. Titi Candra Sunarti M.Si.
BY:
DEANDRA VANYA WISHNU (F3401221801)
DEPARTMENT OF AGROINDUSTRIAL TECHNOLOGY
FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY IPB UNIVERSITY
2023
The Importance of Chicken Egg, its Components, and Uses i. Definition
The chicken egg is the most consumed worldwide food of affordable price, practical cooking, and good nutritional profile. The chicken egg can be classified as the ovum, another name for egg in Latin, of the chicken (Gallus domesticus), it is a highly specialized cell, equipped
specially for the single function of generating a new individual, producing a living organism in a short time (21 days) when supplied with a heat of 42ºC. Chicken eggs are typically many centimeters long compared to human eggs which only make up about 0.1 millimeters. (Alberts et al.
2002) (Zaheed 2015) (Lesnierowski and Stangierski 2018).
Eggs are divided into different weight classes. The
following are the minimum mass per egg and cooking yield
(volume) for each size of chicken egg according to the USDA sizing per dozen:
- Jumbo: 70.9 g or 2.5 oz.; 61 ml (4.75 tbsp)
- Very Large or Extra-Large (XL): 63.8 g or 2.25 oz.; 56 ml (4 tbsp) - Large (L): 56.8 g or 2 oz.; 46 ml (3.25 tbsp)
- Medium (M): 49.6 g or 1.75 oz.; 41 ml (2.75 tbsp) - Small (S): 42.5 g or 1.5 oz.; 34 ml (2.25 tbsp)
Current global per capita egg consumption estimates to approach 9kg annually, however it varies greatly on a regional basis. More than 50 billion chickens are raised annually as a source of food, utilizing both their meat and eggs. Chickens those are raised specifically for their eggs are called layers, where hens lay eggs when they reach 21 weeks old. Commercial laying hens produce 180 to 200 eggs a year on average while in more temperate climates laying hens can produce 250-300 eggs a year. (Zaheer 2015).
ii. Composition
The egg consists of a yolk in the centre, surrounded by albumen (the white of the egg, both enclosed within the egg shell (Figure 3). In a whole, raw, and freshly laid egg, water, protein, fat,
Figure 1 Shows the comparison of a chicken egg to the size of a human egg. (Alberts et al. 2002)
Figure 2 Basic composition of the edible parts of the egg (a) Egg white; (b) Egg yolk (Réhault-Godbert 2019)
carbohydrates, and ash represent about 76.1%, 12.6%, 9.5%, 0.7% and 1.1% respectively.
The shell, albumen and yolk make up 9-12%, 60%, and 30%
of the egg respectively. The egg white (albumen) is a natural source of incredibly high-quality protein, consisting of 87.72%
water, 10.82% protein, 0.85% carbohydrates, and 0.19% fats (Figure 2). The yolk is classified as one of the biggest biological cells, reserving nutrients for developing an embryo, it is rich in lipids, proteins, minerals, and polysaccharides, consisting of antioxidants, aromatic amino acids, carotenoids lutein and zeaxanthin (responsible for its yellow/orange color) (Figure 4), liposoluble vitamins (vitamin A and E), vitamin B12, cholesterol, and phospholipids. The yolk is a pseudoplastic non-Newtonian mass and a highly complicated system of emulsified protein-lipid complexes. The eggshell also provides supplies minerals, one of the most important is calcium. Shell color depends on the hen’s genetics, it varies from color to color but are most commonly white or brown but may be blue or green. (Alberts et al. 2002) (Santos 2018) (Lesnierowski and Stangierski 2018). Egg composition is relatively consistent in terms of total protein, essential amino acids, total lipids, and phospholipids. The other components mentioned above such as fatty acids, minerals, vitamins, carotenoids, antioxidant, and cholesterol content are influenced by the diet of the hen. (Zaheer 2015).
iii. Benefits
The egg’s main valuable component is as a food ingredient and/or product. The egg can be manufactured, used as an ingredient in certain dishes, or cooked on its own (still retaining 91% of its protein quantity). Among the types of cooking, this includes the fried chicken egg, stir-fried, cooked, pochê, roast, in the form of omelets and soufflés. (Santos 2018). When cooking or boiling eggs, the proteins begin as folded chains but begin to denature and unfold when heated, this interaction between the unfolded proteins create a three-dimensional network, trapping the water and causing the egg to solidify. Albumen pH increases as CO2 diffuses out through the shell, albumen adheres strongly to the shell at lower pH, this is what causes boiled eggs harder to peel.
Figure 3 Chicken egg components.
(Zaheer, 2015)
Figure 4 Chemical structures of lutein and zeaxanthin (ResearchGate).
Many parts of the egg are also beneficial for health and nutrition, providing a source of antioxidants, vitamins, proteins, etc. It does not only provide nutritional value however also acts as a pro-health nutrient which prevents heart diseases and many other illnesses. Egg proteins (typically around 6.5g an egg) contain a perfectly balanced supply of the 9 amino acids essential to human health (histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, threonine, tryptophan, valine). Amino acids are vital for the production of enzymes and hormones in the body, and many other functional components required for growth, tissue maintenance, and regulation of metabolic functions; this is why chicken eggs are important for consumption especially during development stages. Essential long-chain fatty acids (polyunsaturated fatty acids: alpha-linolenic acid (n-3) and linoleic acid (n-6)) contribute flexibility to cell walls and reduce plasma cholesterol levels. Eggs contain several antioxidants which reduce free radicals arising from cellular metabolism. Selenium acts to reduce oxidative stress from free radicals promoting heart disease, carotenoids in egg yolk (lutein and zeaxanthin) prevents cataracts and age-related macular degeneration, vitamin E reduces oxidation of fats in low-density lipoprotein improving cholesterol transportation reducing risks of heart diseases. (Zaheer 2015).
Other than that, further research has demonstrated ways to improve the functionality of eggs by enriching them with extra nutrients, such as vitamins, polyunsaturated fatty acids, trace elements and biocatalysts. There is also a chance to control the yolk's cholesterol content. This method of producing eggs, or "designer eggs," not only serves as a source of nutrition but also functions as a nutraceutical when feeding the hen with appropriate foods that are balanced in desirable ingredients like micro- and macronutrients, omega 3,
xanthophylls, vitamins, and other substances. (Lesnierowski and Stangierski 2018).
iv. Bibliography
Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P. 2002. Molecular Biology of the Cell, 4th edition. (US): Garland Science.
Lesnierowski G and Stangierski J. 2018. What’s new in chicken egg research and technology for human health promotion? – a review. Trends in Food Science & Technology. 71 (46-51).
Réhault-Godbert S, Guyot N, Nys Y. 2019. The golden egg: nutritional value, bioactivities, and emerging benefits for human health. Nutrients. 11(3): 684.
Santos HO. 2018. Update of the impact of consumption of whole chicken eggs on the lipid profile: to what extent are they impacting? Arq Bras Cardiol. 110 (6).
The Role of Lutein in Eye-Related Disease - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Chemical-structures-of-lutein-and- zeaxanthin_fig2_23693210
Zaheer K. 2015. An updated review on chicken eggs: production, consumption, management aspects and nutritional benefits to human health. Food and Nutrition Sciences. 6(13).