RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Flavor of Roquefort cheese, J. N. Curuie (U. 8. Dept. Agr., Jour. Agr. Re- 

 search, 2 {191 Jf), No. 1, pp. 1-14)- — The purpose of this investigation was to 

 identify and explain the occurrence of any substances which are responsible 

 for the peculiar peppery or hot taste present in well-ripened Roquefort cheese. 



The neutral flavor solution of Suzuki et al. (E. S. R., 24, p. 382) from 750 gm. 

 of Roquefort cheese showed a total amount of acidity in ester combination 

 corresponding to 0.44 decinormal cc. The proportional numbers obtained by 

 the Duclaux distillation approximated the constants for acetic acid. The odor 

 of Roquefort cheese suggests that part of its flavor may be due to the presence 

 of ethyl acetate, but the quantity present makes it doubtful whether it would, 

 materially affect the test. It was noted that the amount of volatile Insoluble 

 fatty acids of milk fat increased with the ripening of the cheese, and these 

 when found floating on the surface of the distillate had a peppery taste. 



From five fractious, the barium salts of caproic, caprylic, capric, butyric, and 

 acetic acids were obtained. The chief constituent of the insoluble acids was 

 capric acid. The quantitative estimations made it evident that a small amount 

 of formic acid is present also. The peppery taste of Roquefort cheese is 

 ascribed to the presence of caproic, caprylic, and capric acids and their easily 

 hydrolyzable salts which originate from a hydrolysis of the fat of milk. Evi- 

 dently in the normal ripening of Roquefort cheese very few of the acids 

 originate from the putrefaction of proteins. The small quantity of acetic and 

 formic acids present can result from a fermentation of carbohydrates in the 

 early stages of ripening or they may be the products of a partial oxidation of 

 higher acids or glycerol by mold. 



Studies are also reported on the action of PeniciUiiim roqueforti on butter 

 fat. Czapek's solution, in which cane sugar was replaced by 3 gm. of fresh, 

 filtered milk fat, was employed as the nutrient medium. The results when 

 compared with the controls showed a hydrolysis of about two-thirds of the 

 fat. When the mold was grown on fresh curd " the fat showed decided decom- 

 position, but there was only a meager accumulation of soluble and volatile 

 acids. A culture at the age of 45 days contained only 0.75 decinormal cc. of 

 soluble acids in 500 cc. of distillate. A culture similarly grown but in the 

 presence of Bacillus lactis acidi contained only 0.8 decinormal cc. of soluble 

 acids in a like volume of distillate. The acid number of the fat in both cul- 

 tures showed that more than one-half of it had been, hydrolyzed. . .. . The 

 enzymotic studies show that P. roqueforti is well supplied with an enzym 

 capable of hydrolyzing both simple esters and triglycerids." 



A bibliography of literature cited is appended; 



On the influence of preliminary heating upon peptic and tryptic prote- 

 olysis, A. H. BizARRO (Jour. PhysioL, 46 (WIS), No. 3, pp. 267-284. figs. 6).— 

 " Sorensen's formaldehyde method was applied to the study of the influence of 



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