Division 7.1 Method of calculation

Calculate the sucrose content by means of the following formulae:

1. (1)

   v = $\frac{M}{100}\left(\mathrm{1,08F\; +\; 1,55P}\right)$

2. (2)

   S = $\frac{\mathrm{D\; -\; 1,25l}}{Q}\times \frac{\mathrm{V-v}}{V}\times \frac{V}{\mathrm{L\times M}}\%$

where:

S

sucrose content;

M

mass of the weighed sample in grams;

F

percentage of fat in the sample;

P

percentage Of protein (N x 6.38) in the sample;

V

volume in ml to which the sample is diluted before filtration;

v

correction in ml for the volume of the precipitate formed during clarification;

D

direct polarimeter reading (polarization before inversion);

I

polarimeter reading after inversion;

L

length in dm of the polarimeter tube;

Q

inversion factor, the values of which are given below.

Remarks:

1. (a)

   When exactly 40,0 g of condensed milk are weighed and a polarimeter with sodium light, angular degrees and a 2dm polarimeter tube at 20,0 ^oC ± 0,1 ^oC is used the sucrose content of normal condensed milk (C = 9) can be calculated from the following formula:

   S = (D — 1,25 I) x (2,833 — 0,00612 F — 0,00878 P)

2. (b)

   If the invert polarization is measured at a temperature other than 20 ^oC, the figures should be multiplied by:

   (1 + 0,0037 (T — 20).