Egg yolk in the context of "Placenta"

Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575–585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the RGB color model, used to create colors on television and computer screens, yellow is a secondary color made by combining red and green at equal intensity. Carotenoids give the characteristic yellow color to autumn leaves, corn, canaries, daffodils, and lemons, as well as egg yolks, buttercups, and bananas. They absorb light energy and protect plants from photo damage in some cases. Sunlight has a slight yellowish hue when the Sun is near the horizon, due to atmospheric scattering of shorter wavelengths (green, blue, and violet).

Because it was widely available, yellow ochre pigment was one of the first colors used in art; the Lascaux cave in France has a painting of a yellow horse 17,000 years old. Ochre and orpiment pigments were used to represent gold and skin color in Egyptian tombs, then in the murals in Roman villas. In the early Christian church, yellow was the color associated with the Pope and the golden keys of the Kingdom, but it was also associated with Judas Iscariot and used to mark heretics. In the 20th century, Jews in Nazi-occupied Europe were forced to wear a yellow star. In China, bright yellow was the color of the Middle Kingdom, and could be worn only by the emperor and his household; special guests were welcomed on a yellow carpet.

Separating eggs is a process, generally used in cooking, in which the egg yolk is removed from the egg white. This allows one part of the egg to be used without the other part, or each part to be treated in different ways. Recipes for custard call for egg yolks, for example.

The most common reason for separating eggs is so the whites can be whipped. Also, because cholesterol is only found in the yolk, using only egg whites in a recipe will drastically reduce its cholesterol content.

Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup.They are a major component of biological membranes and can easily be obtained from a variety of readily available sources, such as egg yolk or soybeans, from which they are mechanically or chemically extracted using hexane. They are also a member of the lecithin group of yellow-brownish fatty substances occurring in animal and plant tissues. Dipalmitoylphosphatidylcholine (lecithin) is a major component of the pulmonary surfactant, and is often used in the lecithin–sphingomyelin ratio to calculate fetal lung maturity. While phosphatidylcholines are found in all plant and animal cells, they are absent in the membranes of most bacteria, including Escherichia coli. Purified phosphatidylcholine is produced commercially.

The name lecithin was derived from Greek λέκιθος, lekithos 'egg yolk' by Theodore Nicolas Gobley, a French chemist and pharmacist of the mid-19th century, who applied it to the egg yolk phosphatidylcholine that he identified in 1847. Gobley eventually completely described his lecithin from chemical structural point of view, in 1874. Phosphatidylcholines are such a major component of lecithin that in some contexts the terms are sometimes used as synonyms. However, lecithin extracts consist of a mixture of phosphatidylcholine and other compounds. It is also used along with sodium taurocholate for simulating fed- and fasted-state biorelevant media in dissolution studies of highly lipophilic drugs.

Mayonnaise (/ˌmeɪəˈneɪz/), colloquially referred to as "mayo" (/ˈmeɪoʊ/), is a thick, creamy sauce with a rich and tangy taste that is commonly used on sandwiches, hamburgers, bound salads, and French fries. It also forms the base for various other sauces, such as tartar sauce, fry sauce, remoulade, salsa golf, ranch dressing, and rouille.

Mayonnaise is an emulsion of oil, egg yolk, and an acid, either vinegar or lemon juice; there are many variants using additional flavorings. The color varies from near-white to pale yellow, and its texture from a light cream to a thick gel.

Xanthophylls (originally phylloxanthins) are yellow pigments that occur widely in nature and form one of two major divisions of the carotenoid group; the other division is formed by the carotenes. The name is from Greek: xanthos (ξανθός), meaning "yellow", and phyllon (φύλλον), meaning "leaf"), due to their formation of the yellow band seen in early chromatography of leaf pigments.

Custard is a variety of culinary preparations based on sweetened milk, cheese, or cream cooked with egg or egg yolk to thicken it, and sometimes also flour, corn starch, or gelatin. Depending on the recipe, custard may vary in consistency from a thin pouring sauce (crème anglaise) to the thick pastry cream (crème pâtissière) used to fill éclairs. The most common custards are used in custard desserts or dessert sauces and typically include sugar and vanilla; however, savory custards are also found, e.g., in quiche.

An entremet or entremets (/ˈɒntrəmeɪ/; French: [ɑ̃tʁəmɛ]; from Old French, literally meaning "between servings") in Medieval French cuisine referred to dishes served between the courses of the meal, often illusion foods and edible scenic displays. The term additionally referred to performances and entertainments presented between the courses. After the mid-17th century, the term referred to certain types of savory and sweet culinary preparations, and to the stage of the meal in “Classical Service” when they were served. Since the early 20th century, the term has more commonly referred only to the sweet preparations of the entremets stage of the meal.

In the Late Middle Ages and the early modern period, an entremet marked the end of a course of the meal and could be a culinary preparation like frumenty (a type of wheat porridge) that was brightly colored and flavored with exotic and expensive spices, or elaborate models of castles complete with wine fountains, musicians, and food modeled into allegorical scenes. By the end of the Middle Ages, entremets had also evolved into dinner entertainment in the form of inedible ornaments or acted performances, often full of the symbolism of power and regality. In English, such displays were more commonly known as a subtlety (also sotelty or soteltie); they did not typically include acted entertainment, but did include culinary jokes like live blackbirds flying out of a pie, a scene immortalized in the folk song "Sing a Song of Sixpence".

Rouille (French pronunciation: [ʁuj] ; Provençal: rolha, lit. 'rust') is a sauce that consists of egg yolk and olive oil with breadcrumbs, garlic, saffron and cayenne pepper. It is served as a garnish with fish and fish soup, notably bouillabaisse. Rouille is most often used in the cuisine of Provence.