Fruit fermentation lactic acid-fermented products

Since around 1800, the mechanism of fermentation has been studied in a scientific way. It started when German scientist Erxleben discovered that yeast induces fermentation. Louis Pasteur, a French scientist, made many contributions to microbiology. He explained that bacteria produce lactic acid, which then conserves the food. Pasteur also noticed that unwanted fermentation can be stopped by heat treatment of the substrate (pasteurization). This technique is still widely applied today to treat milk or fruit juices. Actually, the production of neat lactic acid was also the first nonfood industrial application of fermentation. 

It is used as organic fertilizer, as cattle feed, as substrate for fungi cultivation, or for microbial enzyme production. Further uses are proposed in lactic acid fermentation and adhesives production. The potato fruit liquid by-product is used for protein enrichment and as fertilizer [22, 23]. 

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) ... 

Table 22.4 Problems that may occur during production and storage of lactic acid fermented fruits and v etables...

Coconut water is the liquid endosperm fluid of the coconut fruit which contains high amounts of essential nutrients and minerals. This endosperm fluid is a widely consumed as a beverage in many parts of the world as it provides hydration along with increased nutritional, health and medicinal benefits. In addition to being used as a medium constituent, it also acts as a natural biocatalyst One of the fermented products of coconut water, coconut water kefir, is made by fermenting coconut water with the kefir granules which contain essential lactic acid bacteria and yeast spp. known to have health benefits for a disease-free life. It has many applications in the food industry and functional food market It is used as one of the important constituents in a variety of products or can be consumed as-it-is . It is known to have no undesirable side effects and is said to improve digestioa This paper reviews the functional properties of coconut water, its applications in the food industry and recent advancements in this area. 

For the production of black lactic-fermented olives, the ripe, violet to black fruit is washed and directly allowed to undergo spontaneous lactic fermentation in a 8-10% salt solution. Lactobacilli and yeasts are involved, but the yeasts dominate normally. Fermentation proceeds slowly because the olive skin is not as permeable as after alkali treatment. After fermentation, the olives are packed into glass or plastic containers and pasteurized. The final product has a pH value of 4.5. 8 and contains 0.1-0.6% of lactic acid. The salt concentration is 6-9%. 

The acidity of food is related to the amount of undissociated and dissociated forms of carboxyKc acids and oxonium ions, respectively, that are present. The major substances that give a sour taste in foods are undissociated hydroxycarboxylic acids, citric and malic acids. Often, however, other carboxylic acids occur, such as ascorbic acid in most types of fruits, tartaric acid in grapes, isocitric acid in blackberries, oxalic acid in rhubarb, lactic acid in some dairy products (such as yoghurt), fermented cucumbers, cabbage, oKves, vinegar and propionic acid in Emmental type cheeses (see Section 8.2.6). The acidity of cola drinks is provided by phosphoric acid, sometimes accompanied by citric or other acids. Carboxylic acids also act as bacteriostatic agents and affect a number of biochemical and chemical reactions. 

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