Protein and Amino Acid Content in Four Brands of Commercial Table Eggs in Retail Markets in Relation to Human Requirements

Abstract

Considering the common believe that all eggs in the retail market are nutritionally similar, four different commercial sources of eggs (A, B, C, and D) available in a retail market were collected to investigate the crude protein and amino acid content, as well as the protein quality in the whole edible part of eggs (albumen + yolk), egg albumen, and egg yolk, separately. Five egg samples per source were collected four times during the experimental period, which resulted in a total number of 20 samples that were pooled to finally present five samples per source of eggs. The results show that crude protein in albumen was significantly higher in A and B than that of C and D, but the difference was found among edible parts of eggs such as yolk > whole edible part > albumen. Essential amino acids (arginine, histidine, isoleucine, lysine, methionine, methionine + cysteine, phenylalanine, phenylalanine + tyrosine, threonine, and valine) of eggs significantly differed according to the source of eggs, but eggs from different sources could provide from 17.4–26.7% of recommended daily allowance (RDA) of amino acids for adults. Essential amino acids (EAAs) were higher (p ≤ 0.05) in eggs from sources A and B than in source D, while source C exhibited intermediate values. Source B had greater (p ≤ 0.05) non-essential amino acids (NEAAs) than did sources C and D in whole edible egg, while source A displayed intermediate values. The phenylalanine + tyrosine, histidine, and lysine were the 1st, 2nd, and 3rd limiting amino acids in all sources of eggs. In conclusion, the investigated eggs showed different EAAs/NEAAs ratio and antioxidant amino acids, indicating a potential for enhancing nutritional values and extending the shelf life of eggs by different nutritional additions.

Amino acid requirements for laying hens: a comprehensive review

“…(2018) Lohmann brown 180 - 112 16.0 Secci et al. (2018) Lohmann brown 180 - 111 15.6 Attia et al. (2020) Commercial lines - 139 124 16.0 Abbreviation: Na, not available.…”

“…There is, however, little information in the literature about the impact of dietary amino acids on egg amino acid profiles, and the relevant data are ambiguous. The amino acid composition in eggs varies with breed, age, diet, and environmental settings ( Nimalaratne et al., 2011 ; Attia et al., 2020 ; Mori et al., 2020 ); however, some studies have reported that these factors do not alter the amino acid composition in eggs ( Lunven et al., 1973 ; Secci et al., 2018 ; Attia et al., 2020 ). This disparity may have arisen from differences in the analytical procedures used.…”

“…(2019) (DM basis) Li et al. (2019) (as-is) Attia et al. (2020) (as-is) Arginine 33.5 27.3 32.7 6.10 8.10 Histidine 13.1 12.9 12.9 2.50 3.10 Isoleucine 26.9 22.1 29.3 5.40 6.70 Leucine 45.1 34.2 46.7 8.50 10.9 Lysine 36.9 28.9 41.4 7.50 9.60 Methionine 16.5 16.2 17.4 3.90 3.50 Phenylalanine 30.8 21.2 30.1 6.40 6.50 Phenylalanine - 37.8 52.8 11.6 11.7 Threonine 24.5 21.8 23.7 5.50 6.40 Tryptophan - 6.00 8.70 - 1.40 Valine 33.4 27.8 36.5 6.40 7.40 Alanine …”

Impact on genetic differences among various chicken breeds on free amino acid contents of egg yolk and albumen

“…A potential for enhancing the nutritional values by using genetic and environmental factors have been reported in egg free amino acids 16 , 24 . Since free amino acids contribute to the taste of foodstuffs 25 , 26 , fundamental information of amino acids contents in eggs will lead to increase not only the nutritional values but also food tastes.…”

Total electrolyte balance for laying hens

“…According to PINTO et al, (2002), egg weight is dependent upon the quality and quantity of protein consumed by the laying hens from their diet and can be a useful reference to guarantee their amino acid requirements. The high protein level and amino acid content of the diet remarkably influenced the egg size (ATTIA et al, 2020). In this study, the BET treatment 1250 μeq / kg enabled a good total egg weight (P>0.05) to be attained.…”