Some chemical parameters of kefir production by use of different starter composition
1984
Milkovic, T. | Petrovic, J. (Tehnoloski fakultet, Leskovac (Yugoslavia))
Actual and titratable acidity, lactic and carbonic acid content in the usage of various starter composition were investigated. Bulk cow milk with 6.9-7.4 deg SH acidity and 3.2% fat, kefir grains for obtaining pure kefir culture and lactic acid bacteria cultures of the strains: Str. lactis, Str. cremoris, Str. diacetilactis and Str. filant were used in the investigation. Numbers 1,2 and 3 denote starter compositions, namely:1. pure kefir culture, 2. 3% pure kefir culture and 2% Str. cremoris and Str. diacetilactis and 3. 0.7% pure kefir culture, 0.7% Str. filant, Str. lactis, Str. cremoris and Str. diacetilactis. The following was found: Kefir 1, 2 and 3 was kept 2 or 5 days at the temperature of 7-8 deg C. After 2 days kefir 1 had higher acidity than kefir 2 by 0.50 deg SH, by 1.11 deg SH than kefir 3 and after 5 days it had 0.48 deg SH higher acidity than kefir 2 and 1.42 deg SH than kefir 3. After 2 days kefir 1 had 0.06% more lactic acid than kefir 2 and 0.29% more than kefir 3. while after 5 days it had 0.13% more than kefir 2 and 0.33% more than kefir 3. Kefir 1, compared with kefir 2 and 3, after 2 and 5 days, had a slightly higher carbonic acid quantity. After 5 days in kefir 1 the carbonic acid quantity, compared with the quantity after 2 days, increased by 0.005%, in kefir 2 by 0.001% and in 3 by 0.003%. In all kefirs after 2 and 5 days pH values changed slightly. Storing increases the actual acidity of kefir. Compared with the 2-day kefir, the 5-day one has the pH value lower by 0.3% in all 3 kefirs.
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