To cook starch successfully, it is necessary to swell every grain of starch contained in the starchy food. To accomplish this each grain must be surrounded by heat and moisture. In vegetables and cereals, the cellular framework separates the starch grains so that they are uniformly cooked. Since there is nothing to separate the grains in a powdered starchy substance, as shown in the foregoing experiments, it becomes necessary to mix it with certain materials so that the heat and moisture can penetrate every grain at the same time.
BLANC MANGE
2 cupfuls milk 1/4 cupful corn-starch 1/2 cupful sugar 2 teaspoonfuls vanilla Nutmeg 1/8 teaspoonful salt
Scald the milk in a double boiler. Mix the sugar and corn-starch. Add the hot milk slowly to the sugar and corn-starch mixture, stirring rapidly. Return to the double boiler and cook 30 minutes, stir rapidly until the mixture thickens. Add the salt and flavoring and pour into a mold which has been moistened with cold water. Cool, turn from the mold, and serve with sugar and cream.
If a softer and more creamy dessert is desired, the corn-starch may be reduced to 3 tablespoonfuls. If this quantity of thickening is used, the cooked dessert should be poured into sherbet glasses or other suitable dishes for serving; it will not become stiff enough to mold.
NOTE.--While cooking Blanc Mange, note the number of minutes that is required to thicken the mixture and the length of time of cooking given in the recipe. Why is it necessary to cook the mixture for so long a time after it thickens? (See Cereals.)
CHOCOLATE CORN-STARCH PUDDING
Proceed as for Blanc Mange, using 3/8 cupful of sugar instead of 1/4 cupful. Cut into pieces 1 square (i.e. 1 ounce) of Baker's chocolate. Add to it 1/4 cupful of boiling water. Stir and heat until smooth and thoroughly blended. Add this to the corn-starch mixture just before taking from the fire. Add 1/2 teaspoonful of vanilla. Mold and serve as Blanc Mange.
Note that the quantity of sugar is increased when chocolate is added to the corn-starch mixture. Chocolate mixtures require considerable sugar to make them tasty.
3 tablespoonfuls of cocoa may be substituted for the chocolate. When this is done, mix the cocoa with the corn-starch and sugar and add no water to it. Proceed as in making plain Blanc Mange.
QUESTIONS
Name three substances that can be used to prevent the lumping of powdered cereals used for thickening.
Give the reason for mixing the sugar, corn-starch, and hot milk of Blanc Mange as directed.
For how long a time after placing in the double boiler is it necessary to stir the corn-starch, sugar, and hot milk mixture?
Milk, especially a milk and starchy mixture, scorches readily (see Scalding Milk). From this explain why Blanc Mange is cooked entirely over boiling water, and not over the flame and then in a double boiler, as cereals.
Why is the flavoring not added while the mixture is cooking (see Flavoring Extracts)?
What is the price per package of corn-starch?
How much does a package of corn-starch weigh and measure?
Which material--flour or corn-starch--is the cheaper to use for thickening?
How many persons does the quantity of Blanc Mange above serve?
LESSON XXV
TOAST: DIGESTION OF STARCH
EXPERIMENT 26: CHANGE OF STARCH INTO DEXTRIN.--Place a teaspoonful of flour in a frying pan and heat slowly until it becomes very dark brown and uniform in color. Put a little of the browned flour into a test tube, add water, then shake. Add a few drops of iodine. What indicates the presence of starch? Is starch present?
The starch has been changed to dextrin. Dextrin gives a purple (reddish blue) color when treated with iodine.
EXPERIMENT 27: THE SOLUBILITY OF DEXTRIN.--Pour the remainder of the browned flour from Experiment 26 into a test tube. Add water and shake. Pour through filter paper [Footnote 26: Liquids pass through filter paper, but solids do not. Hence if a mixture of solid and liquid is poured upon filter paper, the liquid passes through, but the solid remains on the paper.] into another test tube (see Figure 30).