Vegetable fermentation lactic acid-fermented products

Lactic Fermentation—in which lactic acid is produced. This is an important fermentation for the preservation of food. Ixtclohacillits bitlgaricus. L, casei. and Streptococcus lartis are used for the manufacture of dairy products, such as sour cream. Lactobacillus plunlariim is used in lhe preservation of certain vegetables, such as the production of pickles and kraut. 

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). 

Lactic acid bacteria and bifidobacteria are preferred as protective and probiotic cultures, and have been used since the beginning of history as starter cultures. They have a long history of being safely used and consumed. LAB are widely used for fermentation of milk, meat, and vegetable foods. In fermentation of dairy products, lactose is metabolized to lactic acid. Other metabolic products, hydrogen peroxide, diacetyl, and bacteriocins may also play inhibitory roles and contribute to improving the organoleptic attributes of these foods, as well as their preservation (Messens and De Vuyst, 2002). 

Ordinary liactic Acid—Lactic acid of fermentation—Optically inactive ethylidene lactic acid—Acidum lacticum (tT. S.)—exists in nature, widely distributed in the vegetable kingdom, and as the product of a fermentation which is designated as the lactic, in milk, sour-krout, fermented beet-juice, and rice, and in the liquid refuse of starch factories and tanneries. 

The lactic acid accumulated during the production of fermented milks and cheeses, besides the related pH drop, represents the key component for the antimicrobial effect of dairy LAB against many spoilage and/or pathogenic bacteria. On the other hand, in some dairy products, and mainly in vegetable-based fermented foods or in intermediate food products such as sourdough, acetic acid released by facultatively or obli-gately heterofermentative LAB can account for an additive preservative effect related to fermentation. 

The production of lactic acid fermented food of plant origin was known in virtually all historical periods and cultures and is still a technology practised all over the globe. Generally it is believed that LAE of vegetables was first practised in China, and from there it is said to have been brought by the Mongols and Tatars to Europe... 

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. 

The final fermented product (pH < 4.1) may either be distributed fresh, packaged or unpackaged, or pasteurized in pouches, cans or jars. In the latter case, the fermented vegetables are first blanched and then filled into the container, poured and after closing subjected to a gentle pasteurization. For victuals that easily soften, the original fermentation liquid should be replaced by a brine containing certain amount of sodium chloride and lactic acid in order to top the containers. 

Starter cultures for lactic acid fermented vegetable products... 

But nevertheless, it can be expected that the use of starter cultures in the manufacture of lactic acid-fermented fruit and vegetable products will gain importance in the future. Some reasons for this are as follows (Buckenhueskes Hammes, 1990) ... 

Starter cultures currently on the market for the production of lactic acid-fermented vegetable products comprise strains of Lb. plantarum. Lb. xyiosus. Lb. cellubiosus and Lb. sakei (strains formerly designated as Lb. bavaricus). 

Exactly the opposite procedure was followed by other chemists/ who began with wood, proteins, starch, sugars, etc., introducing alcohol as a product of the fermentation of sugar, lactic and butyric acids as products of other fermentations, alkaloids following vegetable acids, etc. This was the old system (see ch. VIII). 

Lee K, Lee DS. A kinetic model for lactic acid production in Kimchi, a Korean fermented vegetable dish.J Ferment Bioeng 1993 75 392-4. 

Nguyen DTL, Van Hoorde K, Cnockaert M, De Brandt E, Aerts M, Binh Thanh L, Vandamme P. A description of the lactic acid bacteria mierobiota associated with the production of traditional fermented vegetables in Vietnam. Int J Food Microbiol. 2013 163(l) 19-27. doi http //dx.doi. org/10.1016/j. ij foodmicro. 2013.01.024. 

Lactic acid was discovered in 1780 by the experimental chemist Carl Wilhelm Scheele, who isolated acid of milk from sour whey [12, 13]. A further description of the history of lactic acid by Holten and Benninga shows that industrial production of lactic acid started in the United States in the 1880s [14, 15]. Avery patented and applied a process of fermentation of vegetable sugars [16]. The actual application was the use of a mixture of calcium lactate and lactic acid as baking powder. Unfortunately, this application was not a big success, but other applications in food and textile dyeing were developed. 

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