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Optimization of Fermentation Parameters for the Production of Concentrated Starters from Nonbitter Streptococcus lacti INIA 12
Author(s) -
CHAVARRI F. J.,
PAZ M.,
NUÑEZ M.
Publication year - 1988
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1988.tb07860.x
Subject(s) - fermentation , lactose , food science , skimmed milk , yeast extract , chemistry , incubation , lactic acid , lactococcus lactis , biochemistry , bacteria , biology , genetics
ABSTRACT Streptococcus lactis INIA 12, a selected nonbitter strain, reached its maximum counts and its highest lactic acid production in a culture medium containing 125 g/L skim milk powder, fortified with 5 g/L yeast extract and digested with 10 ppm papain for 20 min at 65°C. Lactose added to the medium did not enhance growth rate or biomass production. A growth temperature of 32°C and the maintenance of pH at 6.80, with 10N NaOH as the neutralizer, were the optimum fermentation parameters in batch cultures. In ten 40‐L fermentations carried out at 32°C and pH 6.80, with a 5% inoculum, a 0.2 kg/cm 2 nitrogen head space pressure and a stirring rate of 80 rpm, maximum counts of S. lactis (10 10 CFU/mL) were reached after incubation for 6 hr at 32°C and pH 6.80.