O N CONDENSED MILK.
BY A. BOERGOL-GNON. The object in analyzing condensed milk is to find whether this product is derived from whole or skimmed milk. ThiR knowledge is obtaincd by reconstituting the original milk, and in so doing one a t least of the constituents of milk m m t be known, otherwise the problem would be indeterminate. Let a, b, c, tl, e , be respectively the water, fat,, albuminoids, milk sugar a n d ash contained in a milk, these constituents together weighing 100 grms. If now we add to this milk .c grms. of cane sugar and evaporate the original water' N , a quaiitit! represented by ay (y fractional) it is evident t h a t 6, c, d, e have not changed in absolute weights, and Lhat the condensed milk obtained from t h e 100 grms. of the original milk will weigh now 100+x-av. Since the analysis givcs for the different constituents, per ceirt., new values a',b', c', d ' , e' in the condensed milk, i t is evident that b of fat, on 100fx-ay total weight of condensed milk, represents on 1 of condensed milk b 100+x-ag and on 100 100 b ---=b' 100-tx-ay b' being the percentage of fat in condensed milk, and in the
161
ON CONDENSED JIILK.
same manner we will have for any other constituent, hr, in the origiiial milk 100 6 .
---
100+x--ay Making lOOfx-ay=D,
-8'
and sinceingeneral @=---we 100 @=--
e
100 e
loo+ X-ay
have
n
Rlld
D 8'
e=-
100 Consequently
D L'
b=-
100 c=-
D c' 100
D a'
a=-
100
e=-
D e' 100 100
I lliis gives, immediately, 100 8 = D 6' and D=--
V
e
and the
Q'
denominator D can be found at once, as soon as we assume h, to be known in tlie original milk, by assuming, n p r i o ~ i any , one of the constituents, n, b, c, d, e, If mc assume ,d, then 100 d
D=--
at
and, knowing D, we can find readily b, c, e and ( 6 by difference from 100. All the constitueuts of the original milk then are found without aoy difficulty by the simplest equations.
A I ' I ' I ~ I ~ ' . \ ' I ' I O ~ 701: T I I E I ' H E ( ' E I ) I S ( T FOHJlLI..l:.
Found a' b' c' d'
i i i coiicleiisctl niilk : 1VJ;Ltel... . . . . . . . . .
. . . . .
.
.
.
F i It . . . . . . . . . . . . . . . . . . . . . . . Illbuniiiioitls. . . . . . . . . I f i l k sug:tI'-. . . . . . . . . . . . . . . . . . . . . . Ash . . . . . . . . . . . . . . . . . . . . . .
(?{
x Cane sugitr..
......................
.
.
25.4';
10.05 !).36
. . .
10.19 l.!E
...
40.01
100 Assumiiig that milk sugar = 4 11. c. in normal milk, we have 1) d' 100 d 100x4 d== =39.25 100' d' 10.19 and 39.25 x 10.05 b=----= 3.94 per cent. F a t : in original niilli.
n=---
100
39.25 x 9.36
--=
c=-
3.67
"
Albuniiiioids
100 39.95 x 10.19
d=---=
4.00
('
31ilk sugar
"
Ash
"
"
'
