weeks the total acidity of the product is 1.7–2.3%, expressed as lactic
acid, with a ratio of volatile to nonvolatile acid of around 1 to 4.
Defects of sauerkraut arise mostly as a result of yeast and mould
growth. These can produce off-odours, loss of acidity, a slimy, softened
product as a result of pectolytic activity, or a pink discolouration due to
the growth of the yeastRhodotorula. In the early stages of fermentation,
Leuconostoc mesenteroidesfermenting sucrose will preferentially utilize
fructose, polymerizing the glucose moieties to produce a dextran slime.
This is however transient and is later degraded and utilized by other LAB.
In some brined and fermented vegetables nutrients are not particularly
well conserved. These tend to employ high salt levels which draw
nutrients and moisture from the product into a high-strength brine
which is often discarded and replaced before consumption. This is not
Figure 9.10 Chemical and microbiological changes during sauerkraut production.K
Total bacterial count;Jlactic acid bacterio;npH;&total titratable
acidity (principally lactic plus acetic);’ volatile acidity (principally
acetic);
(Adapted from Stamer, 1974.)
Chapter 9 339