CHAPTER 12 



Miscellaneous 



Many shorter projects have been carried on at the Institute. Fourteen 

 of these are described in this chapter, and several others have been cited 

 and briefly described in connection with bigger projects. A few of the minor 

 projects are not discussed in either. 



Factors for Color in the Production of Potato Chips 



A research department of a food distributing company inquired of the 

 Institute how to store potato tubers so as to avoid sprouting and get chips 

 of the desirable color even after many months of storage. Denny and 

 Thornton ^^ undertook to answer this question by a study of the effects of 

 temperature and other factors in storage upon the metabolism and sprout- 

 ing of potato tubers. Potato chip production in the United States is a 

 sizable industry ; it consumes fully one-tenth of the total potato production 

 of the country — about 40,000,000 bushels a year. Because of the size of 

 the industry, tubers for chips must be drawn from the main season crop, 

 which demands considerable periods of storage. The researches extended 

 over three years, or seasons, and involved the study of 25 different varieties 

 of potatoes stored under a great range of conditions. In this necessarily 

 brief consideration of these researches only the points of more general 

 interest to the chip industry and facts shomng the significance of storage 

 conditions upon tuber metabolism can be presented. This means that the 

 tables must be greatly abbreviated and many pertinent facts omitted. 

 Those especially interested in the subject will want to read the seven origi- 

 nal articles here cited. 



Reducing Sugars Cause Browning of Potato Chips 



When potatoes are held in commercial storage for a long time it is cus- 

 tomary to hold them at a low temperature to prevent sprouting. This 

 temperature may range any^vhere from 1° to 6° C (approximately 34° to 

 43° F). It is a well-established principle of plant physiology that living 

 plants at low temperatures gradually transform storage fats and starch to 

 soluble sugars. In potatoes it is mainly starch that is transformed to sugars. 

 It was also kno^vn that chips that are fried from tubers long in cold 

 storage give dark broAMi and consequently undesirable chips because of 

 the soluble sugars present in the tubers. Thornton ^^ was the first to show 



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