238
The Acidity, Alcohol Test and Phosphate in Buffalo milk
[ XVII
test and phosphate test at 9 a.m. Acidity was determined by the usual titration against standard
solution of sodium hydroxide with phenolpthalein as indicator. The alcohol test was carried out as
usual by mixing equal amounts of alcohol and milk (2 ml.) but the strength of the alcohol was varied
from 60 to 80 per cent by volume till a positive test was obtained. The method of Ramsdell et al.
[1931] was adopted for the phosphate number, viz., by adding different amounts of 0.5 M. solution.
(68.1 gm. per litre) of potassium dihydrogen phosphate to 2 c.c. lots of milk till coagulation occurred
within 0.02 ml. of the reagent on heating the mixture in a boiling water bath for five minutes. Any
coagulation was taken as positive and the phosphate number was calculated by multiplying the
amount of the reagent expressed in fractional millilitres by 100. The tests were carried out for about
one complete lactation to study the seasonal and lactational variations in the various tests if there
were any. Also two composite samples, one cow and one buffalo, were tested daily for acidity,
alcohol and phosphate tests. Altogether about 1,500 tests were made, each for phosphate number,
acidity and alcohol tests. In the case of the phosphate number, it was a very tedious process to
arrive at the actual amount of phosphate solution required to produce coagulation as the phosphate-
number varied between 8 and 80. Almost a similar difficulty was experienced in the case of the
alcohol test, where also there was considerable variation from sample to sample. The weekly average
of the phosphate number for the individual buffalo milk samples as well as the two composite milk
samples are presented in Table I. The relationship between acidity and phosphate number, acidity
and alcohol test and alcohol test and pho phate number are indicated in Tables II, III and IV
respectively.
TABLE I
Weekly average of the Phosphate numbers of buffalo milk
Week
1st . .
2nd . .
3rd . .
4th . .
5th . .
6th . .
7th . .
8th . .
9th . .
10th . .
11th . .
12th . .
13th . .
14th . .
15th . .
16th . .
17th . .
18th . .
19th . .
20th . .
21st . .
Average .
Buffalo
1
28
27
27
28
29
28
26
25
21
26
30
26
28
26
30
29
30
30
35
32
34
29
Buffalo
2
26
26
25
25
31
24
23
25
28
24
36
33
39
30
28
30
33
34
34
31
24
29
Buffalo
3
31
39
45
45
50
60
48
55
54
51
68
71
68
65
64
59
54
60
58
54
63
55
Buffalo
4
20
25
24
25
22
20
21
21
22
21
32
23
24
26
27
24
26
25
25
26
29
24
Buffalo
5
44
51
50
62
66
58
57
63
66
66
64
72
61
65
65
59
57
62
58
58
53
60
Buffalo
6
26
26
30
28
29
24
25
27
32
29
36
37
35
36
33
31
35
37
32
28
33
31
Average
of six
29
32
33
35
38
36
33
36
38
36
44
44
42
41
41
39
39
41
40
38
39
38
Buffalo
compo-
site
32
30
33
35
36
38
37
40
39
41
40
38
36
41
34
37
33
35
36
35
33
36
Cow
compo-
site
28
47
30
32
31
30
32
33
38
34
35
34
35
30
32
29
28
28
29
28
30
31
DISCUSSION
Acidity
There are considerable variations observed in the acidity of fresh individual samples of buffalo
milk and even for the same individual sample ; day to day variations are so considerable that they
cannot be attributed to experimental error. The average acidity of fresh buffalo milk in the first