Yolk of the Century Egg (Pidan) Contains a Readily Digestible Form of Free Vitamin B₁₂

Abstract

SummaryIn this study, we determined the vitamin B12 content of commercially available century eggs (pidan) and characterized their vitamin B12 compositions in detail. The egg yolk and white of century eggs (each 100 g wet weight) contained 1.960.6 and 0.860.3 mg of vitamin B12, respectively. The vitamin B12 compounds purified from the egg yolk and white were identified as vitamin B 12 using liquid chromatography-electrospray ionization/tandem mass spectrometry. The vitamin B12 present in the yolk or white of century eggs was recovered completely in macromolecular fractions, but not in free vitamin B12 fractions by Sephadex G-50 gel filtration. However, with respect to the vitamin B12 bound to protein in the century egg yolk, approximately 52% of the free vitamin B12 was formed during in vitro gastric digestion and no free vitamin B12 was detected in the egg white.

Food Additives (Hypochlorous Acid Water, Sodium Metabisulfite, and Sodium Sulfite) Strongly Affect the Chemical and Biological Properties of Vitamin B12 in Aqueous Solution

“…These results imply that hypochlorous acid water could not react with food B 12 , which is present in its protein-bound form in food. 26,27 Hypochlorous acid is generated by myeloperoxidase and plays an important role in the innate immune system of mammals. 28 Nevertheless, it was suggested that highly generated hypochlorous acid leads to various diseases due to the action of a potent oxidant protein and induces chlorination and protein aggregation.…”

Preserved food for snakes: predation on naturally made “pidan” eggs in sea turtle nests on the insular beach

“…Therefore, the pH values of the egg yolk and white are relatively low (8.6 ± 0.4 [mean ± SD] and 8.7 ± 0.5, respectively; Teng et al. 2016).…”

“…"Pidan" is an artificially preserved avian egg that is prevented from decomposition. According to the traditional recipes for pidan, salted duck eggs are made by immersing fresh eggs in a brine solution, and the eggs are covered with a mixture, containing salt, ash, and lime (calcium oxide as a strong base), and are maintained for several weeks before wrapping them with rice husks (Teng et al 2016). The formation of pidan is processed by the penetration of alkali through the eggshell and membrane, leading to protein denaturation and hydrolysis in the egg.…”

“…In processing eggs to obtain a semi-solid yolk, the paste or coating fluid has less table salt and lower alkalinity than hard yolk pidan (Hou 1981). Therefore, the pH values of the egg yolk and white are relatively low (8.6 AE 0.4 [mean AE SD] and 8.7 AE 0.5, respectively; Teng et al 2016).…”

Vitamin B12sources and microbial interaction

“…The B 12 present in the yolk of century eggs was recovered completely in macromolecular fractions. 45 However, approximately 52% of the free B 12 was formed from the century egg yolk during in vitro gastric digestion, 45 suggesting that century eggs may be a good source of B 12 .…”