4 CIRCULAR 95 2, U. S. DEPARTMENT OF AGRICULTURE 



planted, one-half of the Turner farm plot that had been exposed to 16 

 applications of insecticide was treated with activated carbon at the 

 rate of 200 pounds per acre. The peanuts, harvested in November 

 1952 were field cured in stacks in the usual manner. 



Soils. — In the spring of 1952 prior to planting of peanuts, soil 

 samples were obtained from 12 of the experimental plots, and at the 

 time of harvesting all plots with the exception of the carbon treated 

 plot, were sampled. 



METHODS 



Preparation of Samples 



Soils. — The preparation of analytical soil samples involved screen- 

 ing, mixing, and subsampling of the crude soil samples. The samples 

 were prepared by the Moorestown, N. J., laboratory of the Bureau 

 of Entomolog} T and Plant Quarantine. 



Peanut Butter. — To insure uniform sampling of the peanuts for 

 palatability testing and for chemical analyses, a portion of each 

 sample was shelled, cleaned, roasted, and processed into peanut 

 butter in a laboratory of the Bureau of Plant Industry, Soils, and 

 Agricultural Engineering. Previous studies on peanut butter pre- 

 pared in this laboratory had shown that it was not possible with the 

 available equipment, to control the roasting process precisely. These 

 uncontrolled variations in roast, affecting both color and flavor of 

 the peanut butter, increased the difficulty of palatability evaluation. 

 To reduce the effect of this variable, the peanuts used for control 

 samples were roasted to light, medium, and dark shades to permit 

 closer matching with the commercial samples during the palatability 

 tests. All samples reserved for testing were stored at 38° F. until 

 needed for scoring and were allowed to come to room temperature 

 before being served to judges. 



Palatability Studies 



Using different sensory testing procedures, two independent sets 

 of ratings of the 1950 and 1951 samples were made by workers in the 

 Bureau of Human Nutrition and Home Economics (BHNHE) and 

 the Bureau of Plant Industry, Soils, and Agricultural Engineering 

 (BPISAE). These groups of workers are hereafter referred to as 

 Panel A and Panel B, respectively. The 1952 samples from South 

 Carolina were rated by Panel A only. 



RATINGS BY PANEL A 



Although all persons serving on Panel A had had some experience in 

 judging foods exposed to BHC, they were given further training before 

 they scored the 1950 samples. As many different brands of peanut 

 butter as could be found on the local market were procured. The 

 panel studied these samples plus additional samples prepared in the 

 BPISAE laboratory, giving special attention to the relation between 

 flavor and dark, medium, or light roasts. As a result of testing nu- 

 merous samples and discussion of the relative flavor quality of each, 

 panel members agreed on one sample as having the most natural 

 peanut flavor; this was used as an overall reference sample with a 

 score of 5. 



In scoring the experimental samples the presence or absence of 

 off-flavor was rated by a panel of 10 judges using a 5-point. scale with 5 



