Description
Lactic acid bacteria convert lactose in milk to lactic acid, lowering pH and creating the texture and flavor of yogurt, cheese, and kefir.
Technical
During fermentation, Lactobacillus and Streptococcus species enzymatically hydrolyze lactose into glucose and galactose, which are then decarboxylated to lactic acid via the Embden–Meyerhof pathway. The accumulation of lactic acid reduces the pH, causing casein micelles to coagulate and form a gel matrix. In kefir, additional yeast and acetic acid bacteria produce CO₂ and kefiran polysaccharide, further thickening the product.
Science
Primary Reaction
lactose → lactic acid (+ CO₂ in some cases)
Sensory Profile
Aroma ()
milkysweetacidiccreamyyogurt-likebutteryfreshslightly funkynuttybarnyard (in aged cheeses)