Hard-boiled eggs

The fish pie wasn t bad, though Aunt Elaine hadn t put hard-boiled eggs in it, which was the bit I really liked. Still, I got one on Sundays if the hens were laying. Mark ate his quickly, and lots of bread, as if he d been hungry for a long time. 

Materials safety glasses, hard-boiled egg, large glass juice bottle with a mouth slightly narrower than an egg, rubbing alcohol, cotton, aluminum pie pan, tongs... 

Eiser et al. (2009) have recently reported on the pH-induced transformation of a hard-boiled egg from a white, brittle particulate gel to a transparent, elastic polymer gel (see Figure 6.20). Eggs were incubated in their hard protective shells for up to 26 days in a strong alkaline solution (0.9 M NaOH + 0.5 M NaCl, pH 12) at room temperature. These harsh experimental conditions are apparently rather similar to those used in a traditional Chinese method developed over two thousand years ago as a way of preserving eggs so that they would remain safely edible for many months. 

Pliny describes a method used by the Egyptians for darkening the surface of silver vessels. The silver is mixed with two thirds of finest Cyprian aes, and a proportion of sulphur equal to that of the silver. This mixture is melted in an earthen vessel well luted with potter s earth. This custom, he adds, has now passed to our triumphal statues, the value of the silver being enhanced by deadening its brilliancy. Silver may also be blackened, he says, by the yolk of a hard-boiled egg, but this color is easily removed by the application of vinegar and chalk. That silver becomes stained by contact with mineral waters and the salty exhalations from them, is doubtless an observation dependent upon the presence of hydrogen sulphide in some spring waters. 

Peanut butter has more protein per gram than a hard-boiled egg, and yet the egg represents a better source of protein. Why ... 

Isolation of Lecithin from Egg-yolk (section 217).— Grind the yolk of one hard-boiled egg with 50 cc. of ether. Filter and wash the solid residue twice with 10 cc. of ether. Evaporate off the ether on the steam-bath, or distil it off from a small flask. Extract the residue twice with hot alcohol, using 10 cc. each time. Pour off the alcohol from the heavy oil through a small filter. Evaporate off the alcohol, dissolve the residue in 10 cc. of cold ether, and add 10 cc. of acetone. Stir until the particles of the precipitated lecithin adhere together and form a ball. Place the latter on a filter-paper. Describe its properties. Boil about one-fourth of the lecithin with about 10 cc. of a 10 per cent solution of sodium hydroxide. Note the odor of the gas evolved. What is it Cool the solution. Is there any evidence of the formation of a soap Filter, dissolve the precipitate in warm water and add dilute hydrochloric acid to the solution. What is precipitated Test a part of the lecithin for nitrogen and for phosphorus ( 58, 59, 61, page 39). 

What happens when the three-dimensional structure of a protein is disrupted Think of the difference between the consistency of a raw egg white and that of a hard-boiled egg. When the forces holding a polypeptide chain in its three-dimensional shape are broken, the protein is unfolded in a process called denaturation. High temperatures can denature proteins, which is why cooking foods that contain proteins results in the proteins denaturation. Denatured proteins form the solid white of a hard-boiled egg. In addition, proteins can be denatured by extremes in pH, mechanical agitation, and chemical treatments. When egg whites are beaten, the proteins are denatured, as shown in Figure 19.4. Because the folded shape of a protein is essential for its function, denaturation of a protein results in loss of its function. This is one reason why organisms can live only in a narrow temperature and pH range. 

Hayashi et al. [3] analyzed the effect of pressure on egg yolk. It is well known from the preparation of a hard boiled egg, that the yolk becomes solid at a slightly higher temperature than the white. The reverse is tme for the effect of pressure the yolk becomes solid at a lower pressure than the white. It is now clear that these observations are the consequence of the unique behavior of proteins. 

Most of US have eaten hard-boiled eggs. They are easy to cook and nutritious. But when was the last time you thought about the process of boiling an egg or looked carefully at a hard-boiled egg A lot of interesting chemical and physical changes occur while an egg cooks. A hen s egg is a complicated biochemical system, but here we will focus on the three major parts that we see when we crack open an egg the shell, the egg white or albumen, and the yolk. The shell protects the inner components from the ontside environment, bnt it has many microscopic pores through which air can pass. The albnmen is abont 88 percent water and 12 percent protein. The yolk contains 50 percent water, 34 percent fat, 16 percent protein, and a small amount of iron in the form of Fe ions. 

The accompanying photo of hard-boiled eggs shows an egg that has been boiled for about 12 minutes and one that has been overcooked. Note that the outside of the overcooked yolk is green. 

The way to distinguish a raw egg from a hard-boiled egg, without cracking the shells, is to spin the eggs. How does this method work ... 

Hard boiled eggs In freshly made salads... 

To increase the solubility of egg proteins from a hard-boiled egg, a new solution containing a surfactant, SDS, for solubilization, and a reducing agent, 2-mercap-toethanol (2-ME), for dissociation, has been introduced [87]. As shown in Figure 16.5, the precipitate after SDS/2-ME extraction is much less than that of Tris-buffered saline, and the recovered protein shows a five-fold increase by SDS/2-ME solution in boiled egg and two-fold in raw egg, which is nearly equal to the theoretical protein content (Table 16.9). 

How can you get a peeled, hard-boiled egg inside a bottle with a neck smaller than the diameter ... 

Why do hard-boiled eggs spin, while raw eggs don t ... 

Wafers are sliced from the boule using a diamond-tipped saw or a set of diamond-coated wires. When the wire saw is used many slices can be cut in one run (like slicing a hard-boiled egg). The substrate thickness essentially depends on the slicing operation, although the final value depends on subsequent polishing operations. 

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