Lactic acid fermentation, sauerkraut

In general, there is a low risk of high amounts of BAs in vegetables and root crops, where BAs are produced as a result of lactic acid fermentation (81,82). Furthermore, the His contents reported in sauerkraut (83,84), cucumbers (85), and green table olives (86) are far below the level of 100 mg per 100 g that has been associated with outbreaks of food poisoning. Nevertheless, a safe evaluation of the products of natural lactic fermentation should take into account other amines, because Tyr, Put, and Cad can also be produced during sauerkraut fermentation (87). Moreover, certain strains of lactobacilli and cocci have been associated with the presence of these compounds in fermented products (82) and synthetic broth (88). 

Pediococcus Fermentation of cabbage to sauerkraut Lactic acid provides sour taste and extends shelf life Gives butterscotch aroma to some wines and beers Production of cheese and yogurt... 

Lactic acid fermented Sauerkraut, carrots, Lb. plantarum... 

As Table 22.2 shows, there are numerous lactic acid fermented vegetables conuner-cially available on the European market up to the present day. This range is complemented by different mixtures of fermented vegetables. Of general economic importance, however, for Europe and the United States, are only three products in the order of quantity produced, these are fermented table olives, sauerkraut and fermented cucumbers. The best-known lactic acid fermented vegetable in Asia is kimchi, which is especially famous as a typical Korean product but is also produced in other Asian countries. Because of its special features, kimchi will be described separately in Section 22.8. 

Figure 22.1 Significant reactions and their most important interactions that take place during the lactic acid fermentation of cabbage to sauerkraut. The bold dotted lines indicate the reactions influenced by the added salt. The bold sohd lines indicate the influence of lowering the pH caused through the microbial production of acids on the entire process. Only permitted in a few countries.

Lactic acid fermentation has been used for mil-lenia for the production of sauerkraut (Fig. 17.7). It was also customary earlier to place the cabbage into acidified wine or vinegar. White cabbage heads are cut into 0.75-1.5 mm thick shreds, then mixed with salt at 1.8-2.5% by weight. The shreds are then packed into tanks of wood or reinforced concrete, coated with synthetics. After the shreds have been packed in layers, they are tamped and weighted down so that a layer of expressed brine juice covers the surface. The lactic acid fermentation initiated by starter cultures occurs spontaneously at 18-24 °C for... 

Lactic acid [50-21-5] (2-hydroxypropanoic acid), CH CHOHCOOH, is the most widely occurring hydroxycarboxylic acid and thus is the principal topic of this article. It was first discovered ia 1780 by the Swedish chemist Scheele. Lactic acid is a naturally occurring organic acid that can be produced by fermentation or chemical synthesis. It is present ia many foods both naturally or as a product of in situ microbial fermentation, as ia sauerkraut, yogurt, buttermilk, sourdough breads, and many other fermented foods. Lactic acid is also a principal metaboHc iatermediate ia most living organisms, from anaerobic prokaryotes to humans. 

Acids and bases are determined by their properties. The word acid comes from the Latin word acidus, which means sour. For example, lemon juice tastes sour because it contains citric acid. Sauerkraut, another sour-tasting food, is cabbage fermented in lactic acid. In fact, sauer (pronounced almost exactly like the English word sour) in German means acid. Sour cream also has lactic acid in it. 

As mentioned in the introduction, fermentation has been used since ancient times to conserve and alter food. Also today, it is still applied on a very large scale for this purpose. A few typical examples are described in this chapter. The principle is similar in most cases. Lactic acid produced by bacteria protects the food from deterioration by inhibiting the growth of mold and other microorganisms. Most vitamins and nutrients of the food are preserved during fermentation. Three examples are discussed in more detail below The production of sauerkraut, soy sauce, and milk products (Table 9.3). 

One example of fermentative bacteria is a group termed the lactic acid bacteria. These bacteria, which are commercially important in the cheese and dairy industry as well as in pickle and sauerkraut production, produce lactic acid by fermenting sugars. 

The process of making dill pickles does not differ much from that of making sauerkraut as far as the fermentation is concerned. The sugars of the cucumbers diffuse out of the cut cucumbers into the liquor and are fermented by lactic acid bacteria and alcoholic yeasts. As in sauerkraut, B. coli communis and allied bacteria are active fermenters producing hydrogen and carbon dioxide. Oidium lactic finally grows on the surface of the liquor and reduces the acidity. 

Products and Uses Produced from milk by the action of lactic acid bacteria when milk is fermented to make cheese. It is also found in other sour foods such as sauerkraut, fermented meats, molasses and is a preservative with some pickled foods such as pearl onions and olives. It is also a normal component of our body. It is produced be muscle activity and normal metabolism and is in our blood and urine. It is a component of all plant and animal tissues and it is impossible to keep out of our diet. Useful as an acid, antimicrobial agent, curing... 

Typical of the microbial succession in sauerkraut fermentation, the so-called betabacteria (heterofermentative lactobacilli such as U>. brevis with higher acid and salt-tolerance than L. mesenteroides) will gradually dominate the population accompanied by a reduction in viable Leuconostoc numbers. The length of the first two stages of sauerkraut fermentation is determined by the temperature, but typically ranges from 3 to 6 days, and is associated with an increase in lactic acid up to around 1% (Muller, 1988). 

Stamer, J. R., Stoyla, B. O., Dunckel, B. E. (1971). Growth rates and fermentation patterns of lactic acid bacteria associated with the sauerkraut fermentation. Journal of Milk and Food... 

In sauerkraut and other fermented vegetables, salt inhibits the growth of undesirable microorganisms and encourages the growth of the lactic acid bacteria. 

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