Vegetable fermentation


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Vegetable fermentation

  1. 1. BIO 421 microbiologyBhalram Bhimraj 08/0702/0462 Marvin Monize 08/0702/3495 Mikhel Naraine 08/0702/3721Carrell Bansavatar 08/0702/0460 Atiya N’djelekulu 10/0702/1830
  2. 2. What is fermentation? General definition: An anaerobic cellular process in which bacteria, yeast or other microorganisms convert organic foods into simpler compounds, and chemical energy (ATP)is produced. Fermentation in food processing: the conversion of carbohydrates into alcohols and carbon dioxide or organic acids by yeast, bacteria or a combination of both.
  3. 3. What is a Vegetable? The Big question is , DOES IT HAVE SEEDS?• If the answer is yes , Then technically ,you have a FRUIT (Matured ovary of a plant and contain seeds)• Some plants may produce a fruit but there are other parts of the plant that are used as food, such as leaf and flowers, these parts are termed the vegetable.• One may say, a vegetable can be any of the edible part of a plant, however these parts must not have seeds present.
  4. 4. Fermentation of vegetables;definition Is a technique used, whereby Starches and sugars in vegetables are converted into lactic acid by the many species of lactic-acid-producing bacteria. This is done by bacteria present in the storage vessels and on the surfaces of vegetables.
  5. 5. The genus Lactobacillus; Members are responsible for lacto-fermentation of vegetables. They comprise of a genus known as lactobacillus. These bacteria get their name (lacto) because they are able to form lactic acid (from sugars). These are "friendly" bacteria that normally live in our digestive, urinary, and genital systems without causing disease. There are over 70 species recognised. Lactobacillus is very heterogeneous genus, encompassing species with a large variety of phenotypic, biochemical, and physiological properties. Most species of lactobacilli are homofermentative, but some are heterofermentative.
  6. 6. Process of vegetable fermentation; usingcabbage to make sauerkraut The process of fermenting begins with washing and cutting cabbages and mixing them with salt, herbs and spices. The vegetables are then pounded until some of their juices are released, then pressed tightly into an airtight container. The salt mixes with the vegetable juice to create a brine which inhibits the growth of putrefying bacteria until the vegetables release enough lactic acid to continue the preservation process, while creating prime conditions for the growth of Coliform bacteria, which are ubiquitous in the air.
  7. 7.  Coliform bacteria produce acids, lower the pH of the kraut, and set the stage for Leuconostoc bacteria to colonize the medium. The Leuconostoc bacteria lower the pH of the sauerkraut further still, thus creating the conditions for Lactobacillus to grow(Katz 2003). Lactobacillus adds the characteristic taste of lactic acid to the food. Lactic acid can create a temporary equilibrium state, which is the ultimate goal of food preservation via fermentation. Refrigeration halts the fermentation process.
  8. 8. Brine salted fermented vegetablesSimilar process to sauerkrautmethod of fermentation15-20% salt solution ispreferredThe salt concentration does notfall below 12%
  9. 9. Non salted, lactic acid fermented vegetablesDoes not involve the addition of saltor brineSinki or other wilted fermented leavesare non salted additivesThis process relies on the rapidcolonisation of the food by lactic acidproducing bacteriaThe process usually takes twelve daysat 30 degrees Celsius
  10. 10. Pit fermentationsThis is an ancient method of preservingstarchy vegetables without the addition ofsaltThe raw materials undergo an acidfermentation within the pit, to produce apaste like substanceFoods preserved in pits can last foryears without deterioration
  11. 11. Means of preservation which allows forgreater shelf-lifeApart from acting as a means ofpreservation, it makes food easier to digest.The fact that the fermented vegetables arenot cooked makes it more nutritious.Makes food safer for consumption