Fermented milks around the World : Kefir
Kefir is a drink, started with the kefir grains that clump together various bacteria and yeasts (vs only 2 bacteria in yogurt).
This leads to a double fermentation (lactic + alcoholic) and develops the sour & fizzy attributes of kefir.
Kefir drinks can also be prepared by fermenting fruit juices, coconut water or molasses. This factsheet will focus on milk kefir.
The cultural origins
The name of “Kefir” comes from Turkish “Keyif”, meaning good feeling.
It is originates from Caucasian mountains in Russia & Central Asia and is popular in Middle East, Eastern Europe and Sweden.
Kefir is now emerging in North America (USA) & Japan for its nutritional goodness.
A specific double fermentation process : milk+bacteria+yeasts
Lactic acid bacteria: Lactobacillus, Lactococcus, Leuconostoc or Streptococcus
- Feed on lactose
- Yield lactic acid: lower pH which coagulates milk proteins
- Release aromatic diacetyl & acetaldehyde
Acetic acid bacteria: Acetobacter occasionally present
- Feed on sugars to yield organic acids
- Some feed on lactose (i.e. Candida or Kluyveromyces)
- Some feed on other sugars (glucose) (i.e. Saccharomyces or Kazachstania)
- Yield CO2 (self-carbonated drink) + alcohol (below 0.05 %) by alcoholic fermentation
Nutrition & health benefits
As all fermented milk product
- Improved digestibility vs milk
- Higher calcium uptake vs milk
- Other effects under study (changes in blood lipid profile, anti-inflammatory properties)
Increased micronutrient density
- After kefir’s yeast fermentation (vit B1, B2, B6, A, niacin, folates)
All the information about Kefir in one infography