itrogen passes in plant and animal
bodies.

CHAPTER II

CHANGES IN COMPOSITION OF FOODS DURING COOKING AND PREPARATION

116. How do raw and cooked foods compare in general composition? 117. In
what ways are foods acted upon during cooking? 118. What causes chemical
changes to take place during cooking? 119. What are the principal
compounds that are changed during the process of cooking? 120. How does
cooking affect the cellulose of foods? 121. What change does starch
undergo during cooking? 122. When foods containing starch are baked,
what change occurs? 123. How are the sugars acted upon when foods are
cooked? 124. What effect does dry heat have upon sugar? 125. What change
occurs to the fats during cooking? 126. How does this affect nutritive
value? 127. What changes do the proteids undergo during cooking? 128.
Why does the action of heat affect various proteids in different ways?
129. Why are chemical changes, as hydration, often desirable in the
cooking and preparation of foods? 130. What physical changes do
vegetable and animal tissues undergo when cooked? 131. How do foods
change in weight during cooking? 132. Why is a prolonged high
temperature unnecessary to secure the best results in cooking? 133. To
what extent is the energy of fuels utilized for producing mechanical and
chemical changes in foods during cooking? 134. What effect does cooking
have upon the bacterial flora of foods? 135. In what ways do bacteria
exert a favorable influence in the preparation of foods? 136. How may
certain classes of bacteria exert unfavorable changes in the preparation
of foods? 137. What are the insoluble ferments? 138. What are the
soluble ferments? 139. What part do they take in animal and plant
nutrition? 140. Define aerobic ferments. 141. Define anaerobic ferments.
142. What general relationship exists between the chemical, physical,
and bacteriological changes that take place in foods? 143. Why should
foods also possess an esthetic value? 144. What kinds of colors should
be used in the preparation of foods? 145. What processes should be used
for removal of coloring materials from foods?

CHAPTER III

VEGETABLE FOODS

146. Give the general composition of vegetable foods as a class. 147.
How do vegetable foods differ from animal foods? 148. Name some
vegetables which contain the maximum, and some which contain the minimum
percentage of protein. 149. Give the general composition of potatoes.
150. Of what is the dr