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How to isolate or cultivate hetero fermentation lactic acid bacteria by nature?

Basically L. brevis i need to cultivate.

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تم إضافة السؤال من قبل Shawal Hameed , Quality In charge , Aljazera
تاريخ النشر: 2017/07/13
dalal alharbi
من قبل dalal alharbi

Lactic fermentation

 "Lactic acid fermentation":

(Mainly sugary) by lactic acid bacteria - through the enzymes they produce - to lactic acid, acetic acid, ethyl alcohol and carbon dioxide - notes that the constituent acids interact with some of the alcohols resulting from fermentation, resulting in esters with smell The desirable earn their own pickles with salt and acidity.

Types of lactic acid bacteria:

There are two types of bacteria involved in the completion of lactic fermentation:

 

 Homozygous Lactic Acid Bacteria, a bacterium that converts sugars during lactic fermentation into lactic acid only.

 Heteroformation Lactic acid bacterium, a bacterium that converts sugars into lactic acid, acetic acid, ethyl alcohol, carbon dioxide and glycerin.

Lactic fermentation usually begins with the activity of mixed lactic fermentation bacteria which lasts for a while and then ceases for a while due to high acidity. Other types of lactic acid fermentation reactivate for a period followed by the activity of mixed lactic bacteria for a period and then the fermentation stops completely.

Conditions for the completion of lactic fermentation:

    The concentration of salt in the solution is within 10%. If the concentration increases during the period of pickling, the activity of the bacteria decreases until it ceases to increase concentration, and the decrease of the concentration of 10% leads to the growth of other types of microorganisms that lead to the corruption of pickles .

    The presence of lactic acid bacteria on the surface of raw materials is necessary, or may be added to the beginning of these bacteria in the absence or in the case of washing materials, usually add the initiator rate of 1/2%.

    Make the fermentation conditions non-aerobic, completely preventing the air which prevents the growth of acetic acid and mycoderma.

    The purity of the table salt used in the pickling. If the percentage of carbonate or sodium bicarbonate, potassium or magnesium increases by 0.1%, this will lead to the equation of the lactic acid produced during the fermentation and the corruption of the pickle and its stain.

    The optimum temperature for lactic fermentation was 30 m 5.

    Addition of 0.1% glucose promotes the activity of lactic acid bacteria.

 Conditions to be considered for the success of the pickling process:

    Vegetables should be fresh - no more than 10 hours of small size - free of fractures or wounds, and small pieces of necks should be left.

    The saline solution brings the concentration concentration of each type, and continues for this concentration for the duration of preservation.

    The concentration of saline solution should be adjusted by adding another amount of salt within 3-4%, after the first few days, so as not to spoil the pickles, because the vegetables are excreted in the first days of the different osmotic pressure outside the fruit from inside, Saline solution.

    The pickles must be completely immersed in saline solution, so that some do not float on the surface, and that the scraper is scrapped if it is on the surface of the solution.

Asif Ahmad
من قبل Asif Ahmad , Professor , PMAS-Arid Agriculture University

Lactic acid bacteria (LAB) are ubiquitous microorganisms that can be beneficial in crop and livestock production. With their long history of use in food preservation by many world cultures (Nordqvist 2004), LAB are generally recognized as safe for human consumption. By producing lactic acid as a fermentation metabolite, these microorganisms prolong storage, preserve nutritive value, and enhance flavors of otherwise perishable foods. LAB are easy to collect and economical to culture, store, and use. This fact sheet addresses frequently asked questions concerning LAB collection, culture, storage, and use in Natural Farming.

How Are LAB Cultured? Step-by-step instructions are given below. Rice grains are readily available, economical sources of LAB. When washing rice with clean water in preparation for cooking, colonies of LAB can be collected in the rinse water. Microorganisms other than LAB are also present, but allowing the rice rinse water to sit for 3 to 5 days will cause LAB to become the predominant species. Since the rinse water is low in nutrients, milk is then added as a food source for the LAB. Fresh cow’s or goat’s milk, which is high in lactose (milk sugar), is an ideal food source for LAB proliferation, or culture. It is best, for obvious reasons, if the milk is unpasteurized and does not contain any antibiotics. After an additional 3 to 5 days, the LAB culture separates into solid and liquid fractions (similar to curds and whey). The liquid fraction is the LAB culture, which can be used immediately, stored under refrigeration, or kept in a cool, dark place with the addition of brown sugar. This edible culture is used in Natural Farming for both plant and livestock production. The solid fraction is edible as a soft cheese and can also be fed to livestock or composted.

LAB Culture Instructions 1. Wash rice grains and collect the first two rinses of cloudy water. 2. Fill a clean glass jar about 2 /3 full with rice rinsewater. Label the jar with date and contents (Figure 1). 3. Cover the mouth of the jar with breathable cloth (such as muslin) or paper (not plastic) and secure with rubber bands or ties to keep out pests. Store at room temperature away from direct light. Be careful not to shake or move the jar while it ferments. 4. After 3 to 5 days, LAB will multiply and give off a slightly sour odor. There will be a mat of semi-solid material floating on the top of the cloudy liquid in the jar. Collect only the cloudy liquid (fermented rinsewater) by pouring off and discarding the mat layer. 5. Depending on the size of your glass jar, measure one part of fermented rinse-water and add 10 parts of milk to fill your jar 2 /3 full. 6. As in step 3, cover the mouth of the jar with cloth or paper and secure with rubber bands or ties to keep out pests. Store at room temperature away from direct light. Be careful not to shake or move the jar while it ferments. 7. After 3 to 5 days, the contents of the jar will separate into a floating solid fraction and a yellow liquid fraction. It may take longer in cooler climates. The yellow liquid is the LAB culture, which must be kept alive. 8. Pour off the liquid fraction, being careful not to mix any solids back into the LAB culture.. 9. Any LAB culture not used within a week should be refrigerated, or if it must be kept at room temperature, add an equal amount (by weight) of brown sugar. In either case, keep the bottle loosely capped to release gases formed by fermentation, or the container may burst. 10. LAB culture may be kept refrigerated for 6 months. Continue to keep the bottle loosely capped to release gases. 11. LAB culture should have a sweet odor; if the odor becomes unpleasant (rotten) after it has been stored, discard it and make a new batch.

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