the case with sauerkraut which uses a low-salt brine and is not desalted
before use. As a result several vitamins are partially conserved, partic-
ularly ascorbic acid, vitamin C. Sauerkraut was used extensively as an
anti-scorbutic (for the prevention of scurvy) in the Dutch navy in the
18th century and was also highly regarded in this respect by Captain
Cook who ordered servings of a pound per man twice weekly during his
voyage of 1772. Some losses of vitamin C will occur during processing, a
50% reduction was observed in the first five weeks of kimchi fermenta-
tion, but nutritional labels on commercial sauerkraut in the United
States usually show an ascorbic acid content of 50% of the Recom-
mended Daily Allowance per 100 g serving.
Kimchi is similar to sauerkraut in some respects since cabbage is a
common ingredient and the level of salt used is low (o3%). It differs
principally in having a shorter fermentation time; the best taste is
claimed after 3 days at 20 1 C when the acidity is 0.6% and the pH
around 4.2. Consequently Leuconostoc mesenteroidesis the principal
organism responsible for the fermentation and dominance ofLactoba-
cillus plantarumis regarded as a defect which results in an excessively
sour product.
9.7.2 Olives
Olives are native to the eastern Mediterranean region where they have
been cultivated since at least 3000 BC. Today 98% of the world’s
hectarage of olives is in the Mediterranean region, most of this going
to the manufacture of olive oil. Substantial quantities ( 4 600 000 tonnes
annually) are also processed into table olives; some are preserved by a
canning process similar to other foods but the production of most types
includes a period of storage in brine during which a fermentation occurs
contributing to the product’s stability. Pickled olives in their various
forms have a complex taste which often requires considerable application
to acquire. In colder climes their consumption has a certain cachet
summed up by the 19th century poet and philosopher Ralph Waldo
Emerson who likened them to life at sea: exotic and distasteful.
In the production of Spanish-style green olives, which account for
38% of world production, the unripe fruits are first treated with lye (1.0–
2.6% sodium hydroxide solution) to hydrolyse the glucoside oleuropein
which imparts a bitter flavour and also inhibits lactic acid bacteria (see
Section 3.2.4). This lasts for up to 10 h during which the lye penetrates
flesh between a half and three quarters of the way to the stone. The lye is
then washed off with water over several hours and the fruits placed into a
brine. Initially this contains 5–6% salt but the level is increased in
strength during the course of the fermentation up to around 8%. Because
some of the natural sugars in the olives will have been removed during
340 Fermented and Microbial Foods