Table 2. Chemical composition (protein concentration and amino acid composition) of egg white and the cholesterol contents of yolks obtained from free-range and conventionally-farmed eggs. The average weight of the egg whites and the egg yolks are also shown.

Names of amino acids	Free-range eggs (g/100 g)	Eggs from conventionally-farmed hens eggs (g/100 g)	Data from Canadian nutrient file (g/100 g)
Non-essential
Alanine	0.45	0.44	0.66
Aspartic acid	1.61	1.54	1.14
Cysteine	0.16	0.15	0.26
Glutamine	1.13	1.10	1.47
Glycine	0.43	0.42	0.38
Proline	0.38	0.37	0.40
Serine	0.56	0.55	0.75
Essential
Arginine	0.54	0.53	0.61
Histidine	0.36	0.35	0.26
Isoleucine	0.26	0.25	0.57
Leucine	0.72	0.70	0.92
Lysine	0.83	0.78	0.75
Methionine	0.20	0.18	0.39
Phenylalanine	0.44	0.42	0.66
Threonine	0.65	0.64	0.47
Tyrosine	0.51	0.49	0.43
Valine	0.72	0.69	0.75
Chemical Composition	Free-range Eggs	Conventional Eggs	CNF Data
Egg white: Total proteinc	10.6 ± 1.1%	9.7± 0.6%	11.8%
Average total weight	65.5 ± 9.0 g (extra-large)	58.5 ± 1.5 g (extra-large)	56 g (extra-large)
			USDA Food Data Central
Egg Yolk:c Cholesterol content	253.4 ± 0.01a (mg/extra-large yolk)	263 ± 0.7b (mg/extra-large yolk)	210 (mg/extra-large yolk)
Average weight of yolkc	17.4 ± 2.1 g	17.1 ± 1.2 g	17 g

Note:

^aFood codes from the CNF: whole, fresh, raw egg (code 125); and egg white (code 126).

^bFood codes from the USDA FoodData Central: Grade A extra-large eggs, 56 g (cholesterol value).

^cValues for average total weights, egg yolks and cholesterol values are for the means and standard deviations for (n = 12).