Selection and preparation of food, laboratory manual

Contents

FIRST SEMESTER

PAGE

Preface 5

Preface

THIS manual was originally prepared for the students of Home Economics in the University of Illinois. This revision embodies some of the suggestions gathered in the years of experience in using the book in the laboratory. It is hoped that the more logical arrangement and the additional material will make the manual useful to a larger circle.

While in some cases the illustrations have been amplified, it has been thought to be neither necessary nor desirable to vary from the general plan of the previous editions, which was to limit the dishes suggested under each head to a number adequate to emphasize the basis for their preparation. This simplicity of plan has been found to be of substantial aid in removing some of the prevailing confusion associated with the study of foods, while at the same time it provides for an almost indefinite expansion and elaboration in cases where more practice work is desired.

A scientific study of food requires some knowledge of pure science in order to understand the chemical composition of foods and to interpret the principles which underlie their selection and preparation. Experience has shown that the principles of cooking may be taught by the same general methods as are used in teaching the principles of chemistry, i. e., by a study of typical compounds. The development of this idea suggests a study of a given food until the student has acquired some familiarity with that type. Thus eggs afford a comparatively pure form of pro- 5 tein with which to determine some of the characteristics of protein foods. Cheese and meat offer further opportunities for such study. In this as in all educative processes, orderly development has its place.

Milk is used early in the experimental work because it is a familiar food and also because it may be easily separated into its constituents, thus affording a concrete illustration of the different classes of foods. Moreover, this procedure offers an easy introduction to the composition of the human body and the functions of different classes of foods. The plan suggested for studying a food is to consider its general aspects in a lecture, its physical and chemical properties in the laboratory, and finally to show how these influence the preparation of a particular dish. For instance, having studied eggs and milk, a custard is a good example of a combination of these materials, and the low temperature used in making it is a result of what has been learned concerning the action of heat on protein.

The selection of the dishes to be prepared is determined by the principles to be illustrated. For example, water as a carrier of flavor is illustrated either by the making of tea or of lemon ice. In addition, the principle of extraction is shown by the former and the physics of freezing mixtures by the latter.

Quality of food materials, proper combinations, care in manipulation, attractiveness of service, normal food requirements, and cost should be constantly considered in connection with the work as outlined.

I. B.

FIRST SEMESTER

PRINCIPLES OF THE SELECTION AND PREPARATION OF FOOD

Experiment i. The Kitchen.

Draw a plan of the kitchen to scale, locating doors, windows, and furniture. Observe :

(a) The kinds of finish used upon the walls, wood-

work, floor, table tops, and sinks.

(b) The means of ventilation.

(c) The arrangement of the furniture. Provision for

storage and disposal of waste.

Experiment 2. Equipment — General.

(a) List the various stoves and burners.

(b) Draw a cross section of:

( 1 ) The coal range.

(2) The gas range.

(c) Measure the height of tables, desks, and sinks.

Experiment 3. Equipment — Individual.

List the equipment of an individual desk. Make a drawing showing :

(a) The size of the working space.

(b) The size of the drawers.

(c) The arrangement of equipment.

(d) The kind of burner.

Experiment 4. Fireless Cooker and Refrigerator.

Draw a cross section of a fireless cooker and of the refrigerator. In the latter indicate the direction of the currents of air in the air passages, the position of the drain pipe and the trap.

What principles of physics are illustrated by the fireless cooker, the refrigerator, and the thermos bottle?

Experiment 5. Use of Coal and Wood.

Open the dampers of the range. Arrange the kindling in the fire box so as to permit the free passage of air through it, using the minimum amount necessary to ignite the larger pieces of fuel placed on top. After satisfactory combustion has been established arrange the dampers :

(a) To heat the oven.

(b) To hold the fire.

( c) To use the open broiler.

Experiment 6. Use of Gas.

Light the various burners of the gas range. Adjust the flame:

(a) To full capacity.

(b) To lowest possible point.

(c) To point of maximum efficiency.

Explain the structure and colors of a flame. Compare the "mixer" of the gas burner with the

damper of the coal range.

Experiment 7. Cost of Gas.

Record the reading of the gas meter on the blanks provided, using the lower space. Make another reading at the

Laboratory Manual Q

end of the month, and compute the gas bill at current rates.

Note. — See instructions on back of blank.

Experiment 8. Consumption of Gas.

From the time required to burn two cubic feet of gas under full pressure, compute the number of feet consumed per hour by each size of burner. Tabulate cost per hour at current rate.

Experiment 9. Economy of Gas.

Compare the amount of gas consumed by a mediumsized gas burner when regulated to maintain the smallest possible show of ebullition in from two to three quarts of water with the amount consumed by the same burner when running at full capacity.

What is the difference in cost per hour ?

Experiment 10. Electricity.

Use an electric cooking appliance. Compare with gas as to convenience, efficiency, and cost at local rates.

1. What are the essentials of a good fuel ?

2. Compare wood, coal, charcoal, gas, gasoline, kerosene, acetylene, and alcohol in reference to these essentials.

3. What is the unit of measure for each fuel ?

4. Develop a score card for judging a fuel.

Experiment 11. Measures.

Determine the :

1. Number of tsp of water in tbsp.

Number of tbsp of water in 1 cup.

Number of cups of water in 1 quart.

io Preparation of Food

2. Number of tsp of flour in tbsp.

Number of tbsp of flour in i cup.

Number of cups of flour in i quart. (Flour to be sifted once before using.)

Experiment 12. Weights.

1. Weight by metric system of :

(a) 1 c flour (c) 1 c water

(b) 1 c sugar (d) 1 c lard

2. Repeat part 1, using avoirdupois.

From above data compute number of cups of flour in 1 pound. Of sugar. Of lard. Using standard measures, what variation may occur in the quantity of material actually taken ?

Experiment 13. Temperatures.

Determine the range of temperature to which food is subjected as indicated by the following scheme. Tabulate the results.