FoodNet

Experimental cookery

1932

Page 275

Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
Sugar. The addition of the non-electrolyte sugar to an egg mixture ele- vates both the setting and curdling temperatures. In large enough quantities it tends to prevent both coagulation and curdling. Its effect in preventing coagulation appears to be proportional to the amount added, the greater the amount added the greater the difficulty in bringing about coagulation. Bancroft and Rutzler state that a "l5-per cent egg white sol was not prevented from coagulating by the addition of 0.25 gram of dextrose to 10 cc. of the sol. However, when the sol was saturated with respect to dextrose heating in boiling water caused no coagulation." Woodruff and Meyer found that 10 per cent of sucrose reduced the gel strength of egg-milk custards heated to 83 °C., approximately one-half. Add- ing 30 per cent of sugar practically prevented coagulation. Adding sugar also increased the translucency of the custard. In the salad-dressing recipe given in Experiment 65, increasing the sugar from Yi to 11 tablespoons (140 grams, about 30 per cent) elevates the temperature for optimum thickness about 4° to 6°C. Here in spite of the fact that the acid tends to lower the coagulation temperature the effect of the large quantity of sugar is still greater and the mixture must be cooked to a higher temperature for optimum thickening. Coagulation by other means. Flosdorf and Chambers found that audible sound, frequencies (1000-15,000), coagulated solutions of egg albumin and synthetic plasterin almost instantly at 30 °C. Jellinek placed a raw egg between two condenser plates connected to a short-wave radio transmitter. After power of 1000 watts had been applied for 5 minutes, the egg yolk was coagulated and hard, as if it had been cooked, but the white was scarcely affected. The temperature of the yolk at the end of this period was 140°F., that of the white was 176°F. The Applications of Factors Affecting Heat Coagulation to Preparation o£ Food Products Custards. As can be deduced from the foregoing discussion, custards containing a high proportion of sugar may not thicken satisfactorily for serving purposes. A small amount of salt aids setting but too much in- creases the tendency to curdle. Pie fillings. One question often asked is why butterscotch fillings for pies which are of a consistency for serving sometimes become thin and runny after standing for a short time. This of course is different from the instances in which thickening does not occur. There may be various factors that bring about this result, but the effect of the sugar in elevating the temperature 338 EGG COOKERY