May 15, 1925 
959 
Fermentation of Sauerkraut 
numbers throughout the greater part of 
the fermentation period. The litmus 
milk is used as a measure of the num¬ 
ber of lactic bacteria which, were added, 
because these organisms form a firm 
smooth curd, free from gas and with¬ 
out whey. They also reduce the 
litmus milk before curdling. The 
highest dilution in which there was 
reduction followed by curd formation 
was taken as the number of lactic-acid 
bacteria present. 
It will be seen from the data in 
Table IV that reduction and curdling 
of the litmus milk takes place at much 
higher dilutions with the inoculated 
brine than with the uninoculated. It 
will also be noted that in all but two 
cases the reduction time precedes the 
curdling time. In these two cases 
reduction probably preceded curd for¬ 
mation, but observations were not 
made at short enough intervals to 
determine exactly when the changes 
occurred with respect to one another. 
ACID PRODUCTION BY THE BACTERIA 
OF KRAUT 
It has been mentioned previously 
that the solutions of sugars, mannitol, 
and litmus milk which had been inoc¬ 
ulated with diluted kraut brine were 
titrated with 0.1 N NaOH at the end of 
10 days. A great number of titrations 
were made, but all will not be given 
here. Table V shows the acidities 
formed from low and high dilutions of 
uninoculated and inoculated kraut. 
This table shows that the acidities 
developed from any of the substances 
used is greater when that substance is 
inoculated with brine from low dilu¬ 
tions than when it is inoculated from 
high dilution. Individual titrations 
may show an occasional exception to 
this rule, but when an average of all the 
titrations for each substance is taken 
it will be found to be true. It was also 
found that for intermediate dilutions 
the acidities developed were between 
those for the low and high dilutions in 
over 80 per cent of the cases. 
These data may be interpreted as 
indicating that in sauerkraut there is 
a complex flora of organism and that 
those organisms which are present in 
largest numbers are not the highest 
acid producers. Bacteria present in 
small numbers are eliminated as the 
dilutions are increased while the more 
numerous but low acid-producing bac¬ 
teria remain. Another explanation is 
the associative action of the bacteria. 
In the lower dilutions a greater variety 
of organisms is found than in the higher 
dilutions. The organisms present in 
the higher dilutions may be incapable 
of producing high acidities due to the 
absence of certain beneficial but non¬ 
acid-producing bacteria. 
CHEMICAL DATA 
The bacteriological data obtained 
tend to show that the bacterial flora 
has been influenced by inoculation 
with selected lactic organisms and that 
these organisms predominate during the 
early part of the fermentation. If this 
is correct, there should be a difference in 
the composition of the inoculated and 
uninoculated kraut. 
Table VI shows the chief fermenta¬ 
tion products found in sauerkraut at 
different periods during the fermenta¬ 
tion. Inoculated kraut shows the 
presence of the characteristic products 
of the added lactic-acid culture, espe¬ 
cially during the early part of the 
fermentation. The inoculated kraut is 
consistently higher in lactic acid and 
lower in alcohol and acetic acid than 
the uninoculated kraut. This differ- 
Table VI .—Chief products found in sauerkraut at various stages in tine fermentation 
Treatment of kraut 
! 
I 
! Age 
0.1 N 
acid in 
100 c. c. 
of brine 
1 Volatile 
acid as 
; acetic 
Non¬ 
volatile 
acid as 
lactic 
Alcohol 
as ethyl 
Total 
reducing 
sugar as 
glucose 
Days 
C. c. 
Per cent 
Per cent 
Per cent 
Per cent 
Uninoculated_ 
3 
76 
0.20 
0.58 
0. 21 
1.76 
Inoculated..._ 
3 
74 
. 17 
.60 
. 17 
1.95 
Uninoculated. .._ 
5 
104 
.30 
.76 
.24 
1.97 
Inoculated.._ _ 
5 
101 
.22 
.80 
.20 
2. 08 
Uninoculated__ 
/ 
152 ; 
.30 
.84 
.25 
1.90 
Inoculated.__ 
7 
160 
.23 
.91 
.22 
1.93 
Uninoculated__ _ _ _ . ._ 
12 
183 , 
.37 
1. 19 
.54 | 
.64 
Inoculated.__ 
12 
174 1 
.36 
1.32 
.31 1 
.91 
Uninoculated__ 
21 
193 
.31 
.62 
. 34 
Inoculated. _._ 
21 
195 
.28 
1.57 
.37 
.96 
Uninoculated__ 
30 
200 
.27 
1.52 
.75 
.33 
Inoculated..._ . _ _ _ 
30 
197 i 
.34 
.53 
. 72 
Uninoculated_ 
73 
188 
. 26 
1. 50 
.60 
. 23 
Inoculated..._ 
73 
! 
184 
.33 
1.69 
.48; 
1 
.30 
