1398 FOODS AND FOOD ADULTERANTS. 



DETERMINATION OF STARCH. 



A small amount of starch is often added to varieties of sausage 

 which are to be boiled to prevent a shrunken appearance. The amount 

 of starch necessary for this purpose, however, does not exceed 2 or at 

 the most 3 per cent. Starch is often added to sausage in considerable 

 amount, both because of its own weight and to permit the addition of 

 a relatively large amount of water, or the use of meat which would 

 otherwise be too fat. 



QUALITATIVE DETERMINATION. 



Five or six grams of sausage are stirred with boiling water for a 

 moment, and the mixture cooled and tested with iodin solution. In 

 using this test it must be remembered that a small amount of starch 

 may be present as a result of the use of spices. If the blue color 

 developed indicates the presence of starch in a larger quantity than 

 would be accounted for by the spices present, the sample may be 

 examined microscopically to determine the variety of starch employed 

 and the quantity estimated. 



QUANTITATIVE DETERMINATION. 



MAYRIIOFER'S METHOD.* 



From 10 to 20 grams of the sample under examination (according 

 as the iodin reaction shows a small or large amount of starch) are 

 treated in a porcelain dish or casserole with 50 cc of an 8 per cent 

 aqueous b solution of potassium hydroxid, and the mixture heated in 

 the water bath until the meat is entirely dissolved. The operation 

 may be hastened by rubbing the larger pieces with a glass rod. An 

 equal volume of 95 per cent (by volume) alcohol is now added and the 

 mixture filtered (after the precipitate has subsided) through a starch- 

 free filter paper and washed twice with a hot 4 per cent solution of 

 potassium hydroxid in 50 per cent alcohol, and then with 50 per cent 

 alcohol until a small portion of the filtrate does not become turbid on 

 the addition of acetic acid. The precipitate and filter are returned 

 to the original vessel and dissolved with 00 cc of a normal solution 

 of potassium hydroxid with the aid of heat. A somewhat larger 

 volume of alkali is required by sausage that has a high starch content. 



The filtrate is transferred to a 100 cc flask, acidified with acetic 

 acid, diluted to a convenient volume, filtered through a ribbed filter, 

 and the starch precipitated from an aliquot part of the filtrate by an 



a Forsch. u Lebensm., 1896, 3, 141, and 1897, 4, 47. 



b Mayrhofer directs that the meat be decomposed by heating with a 4 per cent 

 solution of potassium hydroxid in 50 per cent of alcohol. The writer finds the modi- 

 fication here given to be more convenient and to yield more uniform and satisfactory 

 results. 



