yolk

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yolk

1. the substance in an animal ovum consisting of protein and fat that nourishes the developing embryo
2. a greasy substance secreted by the skin of a sheep and present in the fleece

Yolk

 

(deutoplasm), a nutritive substance that accumulates in the ovum of animals and man in the form of granules or membranes that sometimes merge into a solid yolk mass (in insects, bony fish, and birds).

Yolk has been discovered in the ova of all animals and man, but its quantity and distribution vary considerably. In ova with a small amount of yolk, the yolk particles are distributed evenly throughout the cytoplasm (isolecithal ova). In ova with a large amount of yolk, the yolk particles are concentrated either in the vegetative part of the ovum (telolecithal ova) or in the central part of the cytoplasm, around the nucleus (centrolecithal ova). The type of egg cleavage depends on the quantity and distribution of the yolk. Chemically there are three principal varieties of yolk: protein, fat, and carbohydrate. However, in most animals the yolk granules have a complex chemical composition and contain proteins, fats, carbohydrates, ribonucleic acid, pigments, and mineral substances. For example, in the mature hen’s egg, the yolk contains 23 percent neutral fat, 16 percent protein, 11 percent phospholipids, 1.5 percent cholesterol, and 3 percent minerals. Various organelles of the ovum participate in the synthesis and accumulation of the yolk: the Golgi apparatus, endoplasmic reticulum, and mitochondria. In many animals the protein component of the yolk is synthesized outside the ovary and enters the growing ovum by means of pinocytosis. In some invertebrate animals the yolk may also accumulate in special cells of the ovary—the yolk cells, on which the developing embryo is nourished.

T. B. AIZENSHTADT

yolk

[yōk]
(biochemistry)
Nutritive material stored in an ovum.
The yellow spherical mass of food material that makes up the central portion of the egg of a bird or reptile.
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Gently spoon a quarter of the dried fig paste along the centre of each of the pastry pieces, and brush one side with a little beaten egg yolk and milk.
It is a form of art using paints made of pigment-coloured powder mixed with egg yolk and a pinch of water.
The boffins hope egg yolks of rare birds could now be put in hen eggs to create life.
Br--lee 80g dark chocolate, 5 egg yolks, 300ml double cream, 1 vanilla pod, 1 strong shot of espresso, caster sugar to sprinkle on top.
Egg yolk contains cholesterol and having too much of it increases the risk of atherosclerosis, also known as coronary artery disease.
Spence added the effect of egg yolk consumption over time on increasing the amount of plaque in the arteries was independent of sex, cholesterol, blood pressure, smoking, body mass index and diabetes.
Summary: TEHRAN (FNA)- Newly published research showed that eating egg yolks accelerates atherosclerosis in a manner similar to smoking cigarettes.
But there's a lot more to egg yolks than cholesterol.
In conclusion, to obtain the desired level of RCF values in the egg yolk, the dried vines powder of 'Hatay Kirmizi' having natural carotenoid content can be used as a natural pigmenter in layer diet.