Kefir
Kefir (also, kefir, Bulgarians, Bulgarian yogurt, kefirada milk; yogurt de pajaritos, in Chile) is a dairy product similar to liquid yogurt, fermented through the action of a group of yeasts (fungi) and bacteria (lactobacilli). their production.
In kefir, the lactose in milk is transformed into lactic acid and carbon dioxide and alcohol are also produced in a small amount (1% to 3%) since the milk ferments through a lacto-alcoholic reaction, which occurs in anaerobic condition. There is a bibliography in which it is stated that it comes from the Caucasus region.
Kefir grains or nodules (called "Muhammad pills" in Georgia) look similar to cauliflower but are softer and gelatinous; it is a biotic mass that combines probiotic bacteria, yeasts, lipids and proteins (an example of symbiosis) wrapped in a polysaccharide matrix, called kefiran. The main microorganisms that make up this microbial ecosystem present in kefir are the bacterium Lactobacillus acidophilus and the yeast (unicellular fungus) Kluyveromyces marxianus, although the composition of the microorganisms that make up the kefir vary according to the regions and cultivation methods.
Similarly, although kombucha is another fermented drink that bears no relation to kefir, the terms are often confused due to the erroneous custom of calling kombucha also "tea kefir"; although the tibicos of water are more closely related to kefir.
Milk kefir
Two types of kefir are commonly known: milk and water. In reality, water and milk kefir have the same microflora, but adapted to different environments, there are also distinctions regarding the enzymes present in each other. Kombucha is also usually grouped in the family of these scoby, or symbiotic communities, however, the composition of this differs widely.
The most widespread is milk kefir, with a certain resemblance to yogurt, although making yogurt is much simpler and more cost-effective. However, little by little companies are beginning to appear that are dedicated to the commercialization of kefir, both milk and water.
Currently, the elaboration of kefir at the domestic level is relatively widespread, through people who sell or give away the surplus of nodules (which grow progressively) to others.
Origin
Milk kefir is one of the oldest known dairy products, consumed for thousands of years, from the Caucasus.
Already in antiquity, the peasants of the north of the Caucasus mountains prepared a drink called ayrag, better known as Kumis, leaving the milk still in skins made of goatskin that were never washed. Depending on the season, they were hung near the door of the house, outside or inside. Fresh milk was added to replace the ayrag that was consumed as the fermentation progressed. At a certain point, they observed that the spongy and whitish crust of the inner wall of the skin was capable, if milk was added to it, of giving a different and improved drink of the original ayrag, which was called kefir (képhir, képhyr, kefir).
It is believed that the word kefir comes from the Turkish keif which means pleasant sensation or feeling good, to refer to the pleasant sensation experienced when ingested, and which also carries the connotation of blessing to whom it is given as a gift.
Marco Polo already mentioned it in his stories, and in the XIX century it began to be used as a remedy against tuberculosis.
Composition of the kefir microbiota
Among the different microorganisms that have been identified in kefir, it is possible to find the following species:
Bacteria:
- Streptococcus thermophilus
- Lactococcussuch as:
- Lactococcus lactis subsp. lactis
- Lactococcus lactis subsp. creamy
- Lactobacillus, such as:
- Lactobacillus delbrueckii subsp. bulgaricus
- Lactobacillus casei subsp. pseudoplantarum
- Lactobacillus paracasei
- Lactobacillus helveticus
- Lactobacillus acidophilus
- Lactobacillus brevis
- Lactobacillus fermentum
- Lactobacillus rhamnosus
- Leuconostocsuch as:
- Leuconostoc mesenteroids
- Leuconostoc pseudomessentroids
- Bifidobacteriumsuch as:
- Bifidobacterium infantis
- Bifidobacterium lactis
Yeasts or fungi:
- Kluyveromyces marxianus var. lactis
- Saccharomyces cerevisiae
- Candida inconspicua
- Candida maris.
Preparation
The milk at room temperature and the kefir nodules (usually 60 grams of granules per liter of milk) are placed in a glass or crystal container, closed with an airtight lid (taking into account that you have to leave space or open frequently since gas is produced during fermentation) it is usual also to cover with a cloth cloth with a string, and leave it at room temperature (ideally at 20 degrees or less) 12-36 hours (usually 24 hours) and if possible stirring or shaking every 8 hours or less. After this time, the resulting liquid is strained with a strainer or filter. There are those who wash the jar in water and those who do not, then the process is repeated with more milk. Every 3 or 4 days, some people usually wash the nodules with plain drinking water, although there are people who never wash it or do it very rarely. For a more liquid kefir, add more milk, and for a thicker one, more nodules (or, failing that, less milk). The speed of fermentation is influenced by the ambient temperature, the temperature of the milk and the amount of nodules. The milk should not exceed 39 °C and the ideal room temperature should be around 20 °C. It is recommended to use fresh or pasteurized milk instead of UHT.
The liquid obtained, called kefirada milk or kefir, a probiotic with a consistency similar to yogurt, although with a softer texture and slightly more acidic flavor, is a carbonated, low-alcohol drink. To sweeten its taste, sugar, sweetener, cinnamon or honey are usually added, although all these additives, in order not to interfere with the first fermentation, can be added after having removed the nodules. After fermentation, the kefirada milk can be stored in the fridge at 3 °C/5 °C, maintaining good quality for up to 10 days. Although it is important to note that it will continue to ferment.
Most of the time the product marketed as "kefir" contains much less alcohol and carbon dioxide, due to difficulties in the packaging process, and is actually more properly yogurt.
- Notes
- In principle the kéfir must always be immersed in whole milk (and not in denate or semi-denate). However, there are known cases of kéfir that normally develops in semi- or denate milk, in which case the cultivation should be alternated with whole milk, in order to prevent it from deteriorating.
- You can prepare the desired amount of kéfir, provided the jar is 1/3 air. The reason is that during fermentation a gas pressure is given that increases as the temperature rises. The jar can be filled more if it does not close hermeticly, so that the gas is allowed out.
- Used utensils (recipient and colander) should not be aluminum, because this material is not stable in an acid medium, such as kéfir, and could transfer harmful particles to it[chuckles]required].
There are numerous recipes that use kefira milk to make cheese spreads, solid cheeses, or salads. There are variations depending on the way of preparation. Watery kefir (or kefir d'acqua) is produced from water with sugar, dried fruit, and lemon juice.
Because it contains a low level of alcohol, it is a popular hangover remedy in Russia. There is the Russian method, which allows large-scale production of kefir, and uses 2 fermentations, the second done by adding more milk to kefir, without granules.
Obtaining and conservation
Because kefir nodules can only be grown by dividing other previously grown kefir nodules, kefir has traditionally passed from one hand to another for free. As this grows at a considerable speed, those who cultivate it are forced to give away a part from time to time; since if the fermentation of the milk occurs very quickly, it would take on an overly acidic flavor or even become cut (the more kefir nodules we add to the milk, the sooner the kefirada milk) ferments. It can also be found in herbalists, and there are companies that sell it over the Internet.
Since kefir always has to be in milk, when you don't want to drink kefira milk for a while there are several ways to preserve the grains:
- Refrigeration: In the refrigerator it is ideal to keep it in fresh milk at 4 °C. That's how it stays up to 14 days. For further conservation, milk should be changed every few weeks to feed the crop. It can also be kept in a container with non-chlorinated water and with sugar in the refrigerator for 7-10 days, having rinsed the granules in water previously. The nodules thus preserved need to be reactivated in the next fermentation cycle, as they act more slowly. To do this, you should leave them in fresh milk 2 or 3 days.
- Frozen: cleans well and drains, enters into a plastic bag or táper and freezes. This will take a long time, but with the freeze you will lose much of your initial probiotic power that will recover gradually. To defrost it, it is removed from the freezer and prepared milk for three days, discarding this first kéfir. In cleaning it is not advisable to use tap water because the chlorine it contains can kill the microorganisms of the kéfir.
- Dehydration: puts the kéfir on cooking paper in an airy place, and is removed every time until it is not sticky and has a crystallized look. The time to dehydrate depends on ventilation, temperature and environmental humidity and is 3-5 days for the largest grains. Once dehydrated, they can be preserved in a cool, refrigerator, freezer or dry place. They last about 2-3 months. After this procedure you can even get into an envelope and mail it. To moisturize it, kéfir is inserted into milk for 2 weeks, renewing milk every 2 days. After this process can be prepared milk Normally.[chuckles]required]
Nutritional value
The nutritional value of kefir depends on the quality of the starting milk. In general, it provides minerals, especially calcium, magnesium and phosphorus; rich in B vitamins (B1, B5, B9 and B12, biotin) and vitamin K; essential amino acids, such as tryptophan and easily digestible proteins. Lactose levels decrease and the concentration of the enzyme β-galactosidase increases as a result of fermentation.
Kefiran
The matrix of kefir is wrapped in a water-soluble gelatinous polysaccharide called kefiran, composed mainly of glucose and galactose monosaccharides. Some antitumor, antimicrobial, and healing activity has been found from extracts of this substance.
Functional properties
For a hundred years, kefir consumption has been associated with a number of favorable health effects. Currently documented benefits include modulation of the immune system, metabolism and intestinal flora, and wound healing. In vitro studies have shown anticancer action on various types of cancer cells.
Water and fruit kefir
A clear difference of water kefir with respect to milk kefir is that it does not need lactose to produce fermentation, although it is necessary to add sugar to trigger fermentation, being able to benefit from all the properties that people who are vegan have. Water kefir, unlike milk kefir, remains as carbonated water, while milk kefir remains as sour or acidic milk.
Fruit kefir has the same microbiota and properties as water kefir. The only difference is that fruit kefir is fully adapted to ferment with various fruits.