Experiment 65

To determine the effect of acid upon coagulation of egg in cooked salad dressings. Recipe:

Egg yolks.............. 4 72.0 grams

Sugar................. 1/2 tablespoon 6.2 grams

Liquid total............ 1 cup 240.0 grams

Mustard............... 1/2 teaspoon

Salt................... 1/4 teaspoon

A. Cook in a double boiler. Follow directions under Experiment 64A for cooking. It is not necessary to cook as slowly as under Experiment 64A, but the time for each degree rise in temperature should be the same in all the experiments.

Remove portions of the salad dressing at the following temperatures: 76°, 78°, 80°, 82°, 85°, and 92°C. Note the temperature when the salad dressing coats the spoon.

1. Use 1/8 cup of vinegar, 7/8 cup of water.

2. Use 1/4 cup of vinegar, 3/4 cup of water.

3. Use 1/2 cup of vinegar, 1/2 cup of water.

4. Use 1/8 cup of lemon juice, 7/8 cup of water.

5. Use 1/4 cup of lemon juice, 3/4 cup of water.

6. Use 1/2 cup of lemon juice, 1/2 cup of water.

7. Repeat Al, but add 1 tablespoon flour, 7 grams.

At which temperature is the most desirable texture for a salad dressing obtained with the different proportions of acid? Which proportions of acid give the thicker salad dressing? Does curdling occur at the higher temperatures? From results with custard, what would be the result of increasing the proportion of salt? Which produces the clearer salad dressing, vinegar or lemon juice?

76°

78°

80°

82°

85°

92°

Conclusions.

B. To determine the effect of varying the ingredients and the proportion of ingredients in salad dressings.

1. Repeat 65,2, or 65,5, but increase the salt to 1 teaspoon.

2. Repeat Bl, but increase the sugar to 2 tablespoons.

3. Repeat Bl, but substitute 72 grams of whole egg for the egg yolk.

4. Reduce the egg yolk to 36 grams and add 2 tablespoons (14 grams) of flour.