1917] FIELD CROPS. 341 



Gluten formation in the wheat kernel, G. A. Olson {Washington Sta. Bui. 

 lJi2 {1911), pp. 3-19). — After briefly reviewing previous work, tiie author pre- 

 sents data which tend to show the formation of gluten in the wheat kernel to 

 be due to the synthetic activity of an enzym. The experiments included a study 

 of the effect of temperature on the formation of gluten in Jones Winter Fife 

 and Red Russian wheat in 1914, and in Red Russian and Turkey Red X Blue- 

 stem (Washington No. 536) in 1915, of the various forms of nitrogen groups 

 separated from the flour of the 1914 crop, of the effect of heating for various 

 lengths of time on the formation of gluten in Marquis wheat in 1915, and of the 

 amino nitrogen in Red Russian wheat in 1915. The wheat samples were selected 

 in an early stage of development to determine whether or not gluten was present 

 as such or developed in the kernel as a final product of protein synthesis. The 

 wheat was desiccated at varying temperatures and under varying conditions, 

 including air-drying at room temperature, heating in vacuum pans, and heating 

 in an oil bath. 



Positive evidence that gluten was formed within the kernel and not trans- 

 located as such from other regions of the plant was obtained in the 1914 ex- 

 periments. Fife wheat air-dried at a room temperature of 20° C. showed 24.2 

 per cent wet gluten and 10 per cent dry gluten, while that heated at from 50 to 

 60° showed only 1.4 and 0.7 per cent, respectively. Samples collected six days 

 later than those noted above and air-dried at 20° showed 27.3 per cent wet and 

 11 per cent dry gluten. These larger yields are attributed to the translocation 

 or formation of additional material out of which gluten was formed. A tem- 

 perature range from 30 to 35° under reduced pressure did not materially affect 

 the transformation, the percentages of wet and dry gluten being 22.5 and 9.6 

 respectively, while with a temperature of 40° or over the percentage was re- 

 duced 50 per cent or more. Comparable results were obtained with Red Russian 

 wheat. 



In an effort to determine whether or not the protein materials in the kernel 

 were affected by different temperatures the .separation of the protein groups 

 was made by the author's method (E. S. R., 31, p. 208). The results obtained 

 indicate that the synthesis of the more complex nitrogenous substances was not 

 complete at the time of harvest, and that the samples heated to a temperature 

 which suppressed the transformation of the materials into gluten contained 

 the largest amounts of amid nitrogen. Since these samples were expo.sed to 

 relatively high temperatures under reduced pressure it would be expected that 

 under normal pressure the destructive temperatures would be considerably 

 lower. 



The 1915 experiments conducted in an oil bath obviated reduced pressures 

 and, in addition to the 1914 observations, moisture determinations were made 

 on all samples. Red Russian wheat air-dried at room temperature showed 23.5 

 per cent wet and 10.4 per cent dry gluton. Samples containing 65 per cent mois- 

 ture failed to yield any gluten when heated as low as 40° for 30 minutes. With 

 a reduction in the moisture content some gluten was formed. Samples heated 

 at 50° for 30 minutes after 66 hours desiccation and having 44.73 per cent 

 moisture yielded 13.3 per cent wet and 6.6 per cent dry gluten. 



W^hile enzyms that will cause the formation of gluten have not been isolated, 

 the author believes them to be the active agent. Gluten formation is inhibited 

 by heating to relatively low temperatures, 40 to 45°, and desiccation accelerates 

 gluten formation through the concentration of a solution of the materials upon 

 which the enzym acts. The enzym may be present in the kernel from a very 

 early stage but not functional until the soluble nitrogenous materials in the 

 kernel have became concentrated through a rapid translocation from the leaves, 

 and through desiccation. 



