FoodNet

Experimental cookery

1932

Page 267

Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
Frozen eggs. The use of frozen eggs has increased very rapidly in the last 10 years. The eggs are broken out of the shell for freezing, which gives an opportunity for increasing contamination with bacteria. If eggs are frozen quickly after being broken, little bacterial growth takes place. Swenson and James found that fewer organisms survived quick freezing than delayed slow freezing. They also report that the addition of carbon dioxide to the egg batter just prior to freezing was detrimental to survival of bacteria. Eggs are frozen whole, the whites and yolks being mixed by beating. The whites and yolks are also frozen separately. Freezing alters the physical characteristics of the yolk, as it is more viscous after defrosting. Hence to prevent its becoming so stiff and gummy that it does not mix readily with other ingredients, before being frozen it is beaten and a small percentage of salt, sugar, particularly dextrose, or some suitable edible ingredient is often added. Some of these processes are patented, and the proportion of ingredients added as well as the manner of incorporation are not generally known. Frozen whole eggs, egg yolks, and egg whites are usually prepared in 30-pound lots, though some 10-pound lots are frozen. A pound of frozen whole eggs is equivalent to about 10 fresh eggs. As yet frozen eggs are not on the retail market. Drying. The use of dried eggs is decreasing in the United States, the frozen eggs taking their place in many products. I FACTORS CAUSING DETERIORATION 329 Oil dipping. Oil dipping, shell treating, or processing of eggs is increas- ing rapidly. This process consists of dipping the egg in some kind of oil to seal the pores of the egg shell, thus retaining the carbon dioxide within the egg. Swenson, Slocum, and James report that a special white, odorless, taste- less mineral oil of right viscosity and low enough pour-point (40°F.) has been developed to be applied to the shell at temperatures of 60° to 80°F. They also state that oiling shell eggs, especially by the vacuum-carbon dioxide method, tends to maintain the pH of the egg white at 7.9 =^ 0.3, which is below the optimum for proteolytic activity. Sharp and Wagenen state that if eggs are oil dipped fairly soon after they are laid, the white will have a pH value of 8.0 or less at the end of the storage period. If oil dipping is to be of value in preserving the eggs they must be dipped before too much carbon dioxide has escaped. Factors causing deterioration. The causes for deterioration of eggs may be listed as follows: (1) action of the enzyme trypsin, (2) alkaline hydrolysis, and (3) chemical changes and changes due to bacterial action. The changes brought about by these factors may be speeded up or retarded by temperature and reaction.