664 EXPERIMENT STATION RECORD. 



The carbohydrates of -wheat, maize, flour, and bread, W. E. 



ISt02^E .{['. ^S. JJi'pt. A(/r., Office of U.qjcrinteiif tStatioiia Bid. oJ, pp. 

 7-28). — This is a study of the carboliydnites of winter aud si)riiig 

 wheat, maize, Houl- from winter and sprinj;- wheat and maize, and 

 bread made from the same. Analyses are given of the materials by 

 the ordinary Weeude method, and in addition the individual carbohy- 

 drates are determined by a method described in the bulletin. The 

 carbohydrates determined were sucrose, invert sugar, dextrin, starch, 

 Ijentosaus and hemi celluloses, and fiber. The changes in making bread 

 are discussed and data are given for the bread-making exi)erin)ents. 



"Flour made from wheat undergoes a selective process which leaves the carhohy- 

 drates in dittereut proportions than in the whole grain. Sucrose and crude liber are 

 notably diminished ; invert sugar and pentosans disappear entirely, while the starch 

 and dextrin are proportionally increased. . . . 



"The combined action of moisture, yeast, and heat, as in i^reparing and baking 

 bread, diminishes the sugar and tends to convert the starch into soluble and ferment- 

 able forms. The actual amount of starch thus changed is, however, much less than 

 is generally supposed, averaging in the materials studied not more than 10 per cent 

 of the total starch present. This change occurs iu the more exposed jiortioiis of the 

 loaf. In the interior the starch practically undergoes i.o change. 



"The temperature of the interior of loaves of bread baked in the oriliuary way 

 was never found to exceed 99 C. 



"The total shrinkage iu Aveight during the process of 'raising/ baking, and 

 'airing' bread amounts to from 12 to 20 i)er cent of the total weight of materials 

 used. This loss is, hov,-ever, almost entirely iu moisture which has been added to 

 the flour, and which is removed by evaporation. The total loss of solid or dry matter 

 will not exceed 3 or 4 per cent on the average. 



"Bread contains all of the varieties of carbohydrates found iu the original Hour, 

 and in addition more or less of so-called 'soluble starch' produced by the action of 

 heat upon the normal starch."' 



The imi^ortant feature of these investigations is the attempt made to 

 determine the various carbohydrates directly, instead of groui)iug them 

 together under tlie head of nitrogen-free extract determined by differ- 

 ence. The method has been somewhat changed by further investiga- 

 tion, and in its modified form is given by the author in a more recent 

 paper noted below. 



The quantitative determination of carbohydrates in food stuffs, 

 I, W. E. Stone {Jour. Amer. Chem. Soc, 19 {189?'), No. 3, pp. 183-197). — 

 After discussing the unsatisfactory character of the determination of 

 nitrogen-free extract by difference the author outlines a method for 

 determining the separate carbohydrates in feeding stuffs. This is based 

 upon the successive treatment of the sami)le (1) with boiling alcohol to 

 remove sugars; (2) with cold water to remove dextrin and soluble forms 

 of starch; (3) with diastase or malt infusion to remove starch; (4) with 

 dilute boiling hydrochloric acid to convert the gums, pentosans, heuii- 

 celluloses, etc., into soluble reducing sugars; and (5) with boiling 1.25 

 per cent sodium hydroxid, leaving the crude fiber behind. 



The method is briefly as follows: From 50 to 100 gm. of finely ground 

 or grated material is boiled with 500 cc. of stiong alcohol under a reilux 



