Industrial microbiology practical
LAB3
1
Al-mustansiriyah Uni. Faculty of Science .Department of Laboratories
Sauerkraut fermentation
The word sauerkraut means Sour cabbage or acidic cabbage.
Cabbage is the vegetable used in Sauerkraut preparation, which is a
good source of ascorbic acid, vitamins, and minerals and possesses value
for its salad and culinary properties. However, it is post-harvest losses
are as high as 60 %. Fermentation has been used since the early days of
civilization to preserve food materials and to develop newer products.
Cabbage could be preserved as Sauerkraut, which is an acid fermented
product.
It is a result of natural fermentation by bacteria indigenous to
cabbage in the presence of 2-3 % salt. The fermentation yields lactic
acid as the major product. The lactic acid, along with other minor
products of fermentation gives sauerkraut its characteristic flavor and
texture.
As no starter cultures are involved in this process, this is
referred to as wild fermentation. The normal flora of the cabbage
leaves is relied upon to include the organisms responsible for the
desired fermentation, one that will enhance preservation and
organoleptic acceptability. The floral succession is governed mainly by
the pH of the growth medium. Initially, a coliform starts the
fermentation. As acid is produced, an environment more favorable for
Leuconostoc is quickly formed.
The coliform population declines as the population of the strain
of Lactobacillus builds. As Leuconostoc is the heterofermentative lactic
acid bacterium, much gas (CO2) accompanies the acid production during
this stage. The pH continues to drop, and a strain of Lactobacillus
succeeds in the Leuconostoc. (Sometimes Pediococcus arises instead of
Lactobacillus). The complete fermentation then involves the succession of
