CHAPTER IV 

 CHEMISTRY OF BAKING 



18. Cooking improves the flavor and makes more 

 digestible most articles of food. There are two ways of 

 preparing food from plant sources. One is to heat it in 

 water or other liquid, which softens the connective tissue 

 so that it is easily broken up and the cells set free for the 

 action of the digestive fluids of the body. The other 

 way is to subject the food to 

 dry heat, as in an oven, where 

 a much higher temperature 

 than that of boiling water can 

 be obtained. Plant foods pre- 

 pared in the oven have some 

 water or moisture in them, as 

 liquids are used in mixing the 

 various kinds of flours. Even 

 popcorn, though very dry, 

 bursts open when heated, be- 

 cause the moisture in it turns 

 into steam. 



The heat causes the starch grains of vegetables and 

 grains to enlarge and burst the connective tissue holding 

 them, and also changes a little of the starch into a form 

 of sugar called dextrin, and the part remaining is then 

 easily changed to sugar by the digestive fluids. Striking 

 examples of this change of starch to dextrin sugar are 

 the differences in taste between a raw and a cooked 



STARCH GRAINS 

 In cells of potato as they 



