Experimental cookery

Compare the volume, tendency to shrink, and texture of the souffles. What temperature should the white sauce be when the cheese is added? Would this vary with different kinds of cheese, that is loaf, processed, and cheddar? Would it vary with degree of ripeness or dryness of the cheese? What is a desirable method of making and baking cheese souffle? CHAPTER X EGG COOKERY Structure and composition. The shell forms about 11 per cent of the egg and is largely composed of calcium carbonate with some mag- nesium carbonate, calcium and magnesium phosphates, and organic matter. Century Photos, Inc. Fig. 32. — Showing standing up quality of yolk and white of a fresh and a deteriorated egg. Within the shell is the shell membrane, a thin, semi-permeable membrane made up of two layers, the inner and outer. After the egg is laid, its con- tents cool and shrink. The air cell at the large end of the egg is formed during this shrinkage by separation of the two membranes. For cookery purposes the white and yolk are the important parts of the egg. The white is clear, transparent, and jelly-like. It composes about 57 per cent of the weight of the whole egg. The layer next the shell is a thin 323 324 EGG COOKERY soft white, its relative proportion varying somewhat at time of laying. Fig. 32. Next comes a layer of rather thick, viscous white, containing a larger proportion of mucin than the thin white. Beyond this is a small layer of thin white surrounding the yolk. Schaible, Moore, and Davidson say that the thick, "firm white is of laminated structure, composed of concentric layers containing mucin fibers." If a freshly laid egg is broken Courtesy of Institute of American Poultry Industries and P. J. Schaible, J. M. Moore, and J. A. Davidson, Michigan Fig. 33. — Showing the laminated structure of firm egg white, yolk removed. into a large quantity of distilled water (the thick white having been slit with scissors on one side to remove yolk) and allowed to stand, the mucin and probably some globulin are precipitated at the edge of the cut surface. Six or more sheets or layers, one over the other, can be distinctly seen. Fig. 33. The chalazae are dense cord-like strands of white substance, one on each side of the yolk, which anchor the yolk near the center of the egg. They allow the yolk to revolve. Being dense the chalazae are not broken down readily when the egg is beaten, hence they are often caught on the blades or wires of the egg beater. COLOR OF SHELL AND YOLK 325 The yolk forms about 32 per cent of the whole egg. It is separated from the white by a yolk sac, called the vitelline membrane. The yolk is made up of layers. See Fig. 34. The fat is more concentrated around the germ spot; hence its specific gravity is less and when the egg is turned the yolk rotates so that the germ spot is always uppermost. In eggs of average size the white usually averages about 30 grams and the yolk about 18 grams. Composition. The composition of the white is approximately 86.2 per cent water; 12.3 per cent protein; 0.2 per cent fat; and 0.6 per cent Blastoderm Air Cell Xhalaza Chalaza White Yolk Yolk Vitelline Membrane Dense Albumen Fluid Albumen I L Layers of White Yolk Courtesy of Institute of American Poultry Industries. Fig. 34. — Diagram showing internal structure of an egg.