K. T. ACHAYA 0AND B. N.
BANERJEE
153
TABLE III—contd.
R. M. and dispersion in old ghees—contd.
Sample
Porbandar samples :
1, January 1942
2, February 1942 .
3. March 1942
4. 'pril 1942
5. y 1942
6. June 1942
7. July 1942
8. August 1942
9. September 1942 .
10. October 1942
11, November 1942 .
12. December 1942 .
13. January 1943
R. M.
value
15.7
17.4
17.3
15.6
20.5
19.5
29.7
33.6
25.9
20.4
16.2
. .
Scale readig
4358
46° 6.5'
46° 2.2'
46° 15.5'
46° 7.9'
5460
44° 12'
44° 8'
44° 22'
44º 15'
Rafractive index
n4358
1.47419
1.47461
1.47331
1.47394
n5460
1.46464
1.46604
1.46464
1.46534
n4358—n5460
.00855
.00857
.00867
. 00860
Solidified at 40° C. and reading could not be taken
48° 11.5'
46° 5.5'
46° 8.4'
46° 24.8'
46° 27.1'
46° 17.3'
46° 14.2'
46° 5.8'
44° 17'
44° 11'
44° 14'
44° 30'
44° 32'
44° 23'
44° 20'
44° 11'
1.47370
1.47429
1.47401
1.47239
1.47216
1.47313
1.47344
1.47426
1.46514
1.46574
1.46544
1.46385
1.46365
1.46454
1.46484
1.46574
. 00856
. 00855
. 00857
. 00854
. 00851
. 00859
. 00860
. 00852
R. I.
n D
1. 4560
1. 4570
1. 4568
1. 4571
1. 4571
1. 4561
1. 4561
1. 4550
1. 4559
1. 4550
1. 4561
1. 4561
The former observation that the R.M. has no effect on the dispersion is again borne out; the.
effect of storage is again to lower the value. The effect of addition of likely products of rancidity
to fresh ghee was therefore studied using a high figure of 5 per cent in order to obtain an appreciable
difference in dispersion.
TABLE IV
Rancidily products in ghee
Sample
1. Pure ghee .
.
.
.
.
.
.
2. Ghee+5 per cent oleic acid
.
.
.
.
3. Ghee+ 5 per cent acetic acid
.
.
.
.
4. Ghee+5 per cent lactic acid
.
.
.
.
5. Ghee+ 5 per cent stearic acid .
.
.
.
6.Ghee+5 per cent alchohol
.
.
.
.
Scale reading
4358
46° 23.8'
46° 20.6'
46° 49.7'
48° 6.1'
46° 28.2'
46° 43.4'
5460
44° 31'
44° 28'
44° 56'
46° 11'
44° 34'
44° 50'
Refractive index
n. 4358
1.47249
1.47281
1.46993
1.46254
1.47205
1.47054
n. 5460
1. 46375
1. 46405
1. 46127
1. 45390
1. 46345
1. 46186
n4358—
n5460
. 00874
. 00876
. 00866
. 00864
. 00860
. 00868
In all cases except that of oleic acid the dispersions fell, as is to be expected from their own low
dispersion values (cf. International Critical Tables, 1930). It is to be noted that Fryer and Weston
[1918] obtained a rise of dispersion on the addition of free acids obtained from whole oils. This
is obviously due to (1) differences in the composition of free acidity and the component acids of a fat.
and (2) the fact that the oils used by them were those containing high proportions of oleic which.
as just remarked, has a high dispersion. It can also be theoretically shown that the dispersion of
a fatty acid mixture containing the likely components [cf. Rangappa and Banerjee, 1946] oleic (60
per cent), butyric (12 per cent), caproic and caprylic (10 per cent each) and say lauric (the remain-
ing 8 per cent), would be less than that of ghee.
The method commonly used for the refining of rancid ghee is that of neutralization with aqueous
alkali followed by thorough washing with water. It was thought useful to decide if the neutraliza-
tion of rancid ghee would bring the dispersion back to the range of fresh samples. Four high-acid
ghees were therefore examined with the results shown in Table V.