VI. 

 ANALYSIS OF BREAD, ETC. 



"For the analysis of white bread it is best to take a whole 

 roll, weigh it, cut it up over a sheet of paper into slices about 

 a centimeter thick, place them without loss in an evaporating- 

 dish, weigh again as a check, heat on the water-bath or in an 

 air-bath until the pieces are dry enough to be powdered, let 

 cool, weigh, grind, and place the powder in a tight glass- 

 stoppered bottle. This material is used for the analysis. 

 If the volume of a single roll is too large for this method of 

 procedure, a mixture of the crust and crumb is prepared, 

 which corresponds as nearly as possible to the proportion of 

 crust and crumb of the bread, and with this we proceed as 

 directed above. 



For the determination of the amount of water and ash 

 take 2 to 3 g. of the powder; for the nitrogen determination, 

 ;about 1.5 to 1.8 g., placing 25 to 30 cc. of fifth-normal acid 

 in the receiver (the digestion must be conducted very care- 

 fully at first) ; for the determination of fat, extract about 4 g. 

 in a Soxhlet apparatus, or, better, boil the same quantity 

 with 75 to 100 cc. of dilute hydrochloric acid (1:2) till dis- 

 solved and then extract with ether; the dry residue obtained 

 by evaporating the ether extract must be again dissolved in 

 ether to purify it. For the determination of the carbohy- 

 drates, heat 2 to 3 g. (of course all these quantities are to be 

 .accurately weighed), according to the method of Marker, 

 \with lactic acid solution, etc. (See the "Determination of 



229 



