Description
Thermophilic bacterial fermentation of skim milk producing a dense, acidic yogurt with high protein retention.
Technical
Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus convert lactose into lactic acid at 40-45°C, causing casein micelle aggregation while whey proteins remain soluble. The strained process removes liquid whey, concentrating proteins and creating a thick gel structure.
Culinary Significance
Produces a yogurt with 10-12% protein content (3-4× regular yogurt) and clean acidic flavor, used as both staple food and cooking ingredient.
Science
Primary Reaction
C12H22O11 (lactose) + H2O → 4 CH3CHOHCOOH (lactic acid)
Parameters
Temperature
43°C optimal
38°C to 46°C range
Time
18 hours
12 hours – 24 hours
Equipment
Thermostatic incubatorCheesecloth or microfiltrationSkim milk (<0.5% fat)