Lactic acid-fermented products starter cultures

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). 

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 Bacteria for Dairy Fermentations Specialized Starter Cultures to Improve Dairy Products... 

The most important fermentative reaction used in dairy processing is the homofermentative conversion of lactose to lactic acid. The efficient manufacture of high-quality cultured products, including most cheese varieties, yogurt, and cultured buttermilk, requires a rapid and consistent rate of lactic acid production. Lactic acid helps to preserve, contributes to the flavor, and modifies the texture of these products. Nearly all starter cultures used to produce acidified dairy products contain one or more strains of lactic streptococci, because these organisms can produce the desired acidity without causing detrimental changes in flavor or texture. Strains of lactic streptococci can be classified as... 

Microorganisms are, however, also used to produce and finish foodstuffs and to preserve them by fermentation (c.f. chapter 2.2 and 3.2.1.1.2). The production of high quality beer or wine would be inconceivable without yeasts. Cured sausages with their typical lactic acid starter cultures and sometimes with mould cultures on their surface also depend on microorganisms. 

Foods that include the incorporation of microbial metabolites as part of their production are an intricate component of the world s food supply and for ethical and sensory-nutritional reasons it is essential for all the world s population to have access to this form of food. It is a process that has been in use since the early history of mankind. An Egyptian pot dating from 2300 BC (McGee, 1984) was found to contain residues of cheese and in passages in the Bible the use of some kind of fermentative starter culture is indicated. It is, therefore, possible that the use of bacteria such as the lactic acid bacteria (LAB) dates back at least four to five thousand years, although the exact principle behind the process may not have been known to the civilizations of those times (Davidson et al., 1995). Production of fermented foods, where organisms such as the LAB are involved, is a technological process that has been used for centuries at least (Herreros et al., 2005). 

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). 

Low Molecular Weight Carbonyl Compounds. In the dairy field, a major product made this way is starter distillate. The main component is diaceyl which is a very important aroma compound responsible for the characteristic buttery flavor of fermented dairy products such as sour cream or buttermilk. The dairy industry relies upon fermentation by lactic streptococci for the production of diacetyl in cultured products. Starter distillate is a natural product rich in diacetyl which is produced by distilling such lactic cultures. The key intermediate in the biosynthesis of diacetyl is aL-acetolactic acid which is decarboxylated to form diacetyl (Figure 3). The starting material of the biosynthetic pathway is citrate which is a natural component of milk. 

In the food production field - and product development - starter cultures, which greatly increase the efficiency of fermentation, have been produced. The technology was improved mainly by application of lactic acid-producing bacteria and yeast fungi, which led to higher quality products. 

---