Egg Yolk Protein and Egg Yolk Phosvitin Inhibit Calcium, Magnesium, and Iron Absorptions in Rats

Abstract

Egg yolk decreases the absorption of iron. The effects of egg yolk protein and egg yolk phosvitin on the absorption of calcium, magnesium, and iron were investigated by in vivo studies. Male Wistar rats were fed purified diets containing casein, soy protein, or egg yolk protein for 14 d. The apparent absorptions of calcium, magnesium, and iron in the rats fed the yolk protein-based diet were lower than those in rats fed the casein- and soy protein-based diets. The apparent phosphorus absorption and the apparent protein digestibility in the yolk protein group were lower than those in the casein and soy protein groups. In the feces of the yolk protein group, serine comprised more than 30% of the amino acids. The addition of egg yolk phosvitin to the casein diets at levels of 1% and 2% (w/w) produced effects on calcium and magnesium absorptions similar to those produced by the diet containing yolk protein. The tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern suggested that phosphopeptide fragments having molecular masses of 28, 22, and 15 kDa were evident in the contents of the small intestine of the rats fed phosvitin diets. These results indicate that yolk protein, when compared with casein and soy protein, decreases calcium and magnesium absorption via the resistance of phosvitin to proteolytic action.

Effect of Neutrase, Alcalase, and Papain Hydrolysis of Whey Protein Concentrates on Iron Uptake by Caco-2 Cells

“…It was reported that some proteins, such as egg yolk protein 58 and casein, inhibited bioavailability of iron, which was caused by formation of 59 insoluble iron-protein complex, or presence of compete minerals (e.g. calcium in 60 casein (4)(5)(6)(7). Proteins and peptides, mainly from milk and meat, enhance iron 61 absorption were also reported (8)(9)(10).…”

Beneficios y barreras percibidos para consumir alimentos de origen animal entre embarazadas de diferente nivel socioeconómico - Lima

“…Así, el alto valor nutritivo fue el beneficio más reconocido de los AOA, aunque las de NSEB pensaban que los huevos y lácteos eran fuente de hierro, lo que es incorrecto, pues esos alimentos tienen factores que inhiben su absorción y que lo convierte en hierro de baja biodisponibilidad (26,27) ; esto indica que es indispensable resaltar como mensaje en la consejería cuáles son aliFigura 2. Barreras percibidas para el consumo de alimentos de origen animal según embarazadas de diferente nivel socioeconómico-Lima.…”

Phosvitin phosphopeptide preparation using immobilised trypsin and enhancing calcium absorption in growing rats

“…The native structure of phosvitin is more stable and resistant to the proteolytic cleavage by trypsin because of containing a high amount of serine and phosphoric amino acids, and chelating of Fe, which results in low in vivo bioavailability (Ishikawa et al 2007). Although it could be digested with trypsin after dephosphorisation, it is always time-consuming and difficult to separate free enzymes and products in the production of phosvitin phosphopeptides.…”