260 EXPERIMENT STATION RECORD. 



ji nutritive staiuipoint. " Frosted wheat, as we have frequently shown, is pos- 

 sessed of a higher percentage of protein than similar wheat that has come to 

 a normal ripeness witliout frost: it is, in other words, immature wheat. It 

 might be argued that tliis exi)lanation would only a])ply in a consideration of 

 the lower grades — those showing the effects of frost — but it is not improbable 

 owing to the liackward season last year that in some districts at least a con- 

 siderable amount of wheat was cut in a 'greener' condition than usual and 

 that this failed to thoroughly ripen in the stook." 



The relationship of the weight of the kernel to wheat per bushel and the 

 percentage of straight grade flour was not as obvious, according to the author, 

 as in earlier work, and the same was true of the relationship between protein, 

 gliadin and dry gluten, observed in normally ripened wheats. " The absence 

 of this relationship probably results from the effect of frost, so observable in 

 the lower grades. 



" Xo differentiation of the flours can be made from their protein content ; 

 throughout the series there is no marked departure from the average (12.24 

 per cent). 



" The flours of the first three grades give somewhat higher results for gliadin 

 and gliadin ratio than do those of the lower gi'ades. This may point to some 

 relation between maturity and gliadin content, the more fully ripened wheat 

 containing the larger proportion of gliadin. . . . 



" The percentages of water-soluble constituents in the flours increase from the 

 first to the last of the series, the increase being chiefly in the nitrogen and ash- 

 free extract or carbohydrates. This agrees in a measure with the sugar results 

 as obtained from both aqueous and alcoholic solutions, but does not fall into 

 line with the data for the volume of loaf produced. There is here no confirma- 

 tion of Wood's theory "[E. S. R., 19, p. 457] that volume of loaf increases wilh 

 the percentage of sugar present; indeed the evidence is directly to the contrary. 

 It is, however, only right to add that in this series there may be a disturbing 

 influence from the presence of immature or frosted grain. 



" The exact nature of the water-soluble carbohydrates of the flours is unknown 

 but is evidently worthy of study. As the volume of loaf is seen to dec^rease 

 with the increase of this component it seems more than probable that volume 

 is influenced by the amount of soluble constituents, or at all events that such 

 is the case in flours from immature or frosted wheats. 



" The results of the present series lend some couflrmation to Wood's theory 

 that the shape of loaf is influenced by the ratio to the protein (or total nitro- 

 gen) of the soluble ash constituents." 



The chemistry of strength of wheat flour, II, T. B. Wood (Jour. Agr. Sci., 

 2 (1907), No. 3, pi>. 267-277, pis. 2). — The experiments reported were made in 

 continuation of earlier work (E. S. R., 19, p. 457). 



The author studied especially the influence of variations in acidity and the 

 amount of soluble salts in flours upon baking quality and the general effect of 

 acids and salt solutions upon the character of gluten. It was found that gluten 

 immersed in distilled water would retain its coherence for some time, probably 

 until bacterial changes occurred, or if the water were frequently changed, until 

 all acids and salts had been removed. In dilute acid solutions, however, gluten 

 began to disintegrate and lose its coherence, while strong acid solutions pro- 

 duced coherence. Common salt added to the solutions tended to maintain the 

 coherence of the gluten, and this relation was studied with different proportions 

 of several salts. 



The experiments reported, according to the author, " show quite clearly that 

 the physical properties of gluten are entirely altered by changing its surround- 



