The analysis of food and drugs / by T.H. Pearmain and C.G. Moor.

  • Pearmain, T. H. (Thomas Hames)
Date:
1897-1899
Catalogue details

Licence: Public Domain Mark

Credit: The analysis of food and drugs / by T.H. Pearmain and C.G. Moor. Source: Wellcome Collection.

    98/332 (page 80)
    Milk-Sugar.—10 c.c. of the solution are made up to 100 c.c. by the addition of 40 c.c. of water and 50 c.c. of ammonia. This gives us a 1 per cent, solution, which is of a convenient strength for the estimation of the sugar by Pavy's method. In applying Pavy's test to milk-sugar, the reagent must be kept boiling briskly while the milk- sugar solution is run in slowly. The reaction takes longer in the case of milk-sugar than in the case of glucose, so that unless the titration is conducted slowly, the milk-sugar solution may be added in excess of the quantity required to complete the reaction. Using ordinary Pavy's solution, it will be found in the case of most condensed milks that about 35 c.c. of the 1 per cent, solution of condensed milk will be equivalent to 50 c.c. of Pavy's solution, and the calculation will be as follows: If 35 c.c. dilute milk = 50 c.c. Pavy's Solution, Or 70 c.c. dilute milk =100 c.c. Pavy's Solution, Or '7 grammes sample =100 c.c. Pavy's Solution, „ „ = '05 grammes of glucose, ma £ 1 '05x100 1 .'. 100 grammes of sample = ^ = grammes glucose. ^■05 X lOOx 100^pe,cent. of milk-sagar 0 X in the original sample. Fat.—Two quantities of 5 c.c. of the solution are placed on two Adams papers, which are well dried and then extracted with dried ether. The method of drying with sand or calcium sulphate, and then extracting with ether, is unsatisfactory, as the fat is extracted with great difficulty. We have attempted to apply the Leffmann-Beam machine to the estimation of fat in condensed milk, and it succeeds fairly well if the following details are adhered to: Place 10 c.c. of the 10 per cent, solution in a Leffmann-Beam bottle with 3 c.c. of the hydrochloric acid and fusel-oil