238 



THE ANALYSIS OF CHEESE. 



He gives the following analyses : 



TABLE XLIII. 



Volatile Acids. The following proportions of volatile acids per 

 100 of fat are instructive : 



TABLE XL IV. 

 Fresh curd, ... 

 Curd five days old, .... 

 ,, eight .... 



Cheese from the same curd two months old, 

 Cantal cheese, ..... 

 Fat from above rancid after one month, 

 Salers cheese (bitter), 



(taste good), . 



Cheese five years old, 



0-04 per cent. 

 0-55 

 2-33 

 3-0 

 3-2 

 9-2 

 8-8 

 2-0 

 71-2 



Van Slyke's Method for the Estimation of the Products 

 of Ripening. Twenty-five grammes of cheese are mixed well 

 in a mortar with an equal volume of quartz sand, and transferred 

 to a flask ; 100 c.c. of water at about 50 C. are added, and the 

 mixture kept at 50 to 55 for half an hour with frequent shaking. 

 The liquid is filtered through cotton wool into a 500 c.c. flask, 

 and the residue is treated 'as before with four further successive 

 quantities of 100 c.c. of water ; after cooling the volume is made 

 up to the mark. 



Water-soluble Nitrogen. This is estimated by the Kjeldahl 

 method in 50 c.c. of the solution. 



Nitrogen as Paranudein. Five c.c. of a 1 per cent, solution of 

 hydrochloric acid are added to 100 c.c. of solution, and digested 

 at 50 to 55 C. till the precipitate has separated completely. 

 The precipitate is filtered and washed, and the nitrogen esti- 

 mated by the Kjeldahl method. 



Nitrogen as Coagulable Protein. Neutralise the preceding 

 filtrate, heat to boiling, and estimate the nitrogen in the pre- 

 cipitate, if any ; coagulable proteins rarely occur in cheese. 



