Effect of ripening cream with selected lactic acid bacteria on the quality of ghee

Abstract

SummaryThe effect of ripening cow'milk cream (40% fat) with 4 strains of lactic acid bacteria on the quality of ghee, an Indian product resembling clarified butterfat, was studied by measuring changes in titratable acidity, pH, volatile acids and diacetyl content due toStreptococcus lactis, Str. lactissubsp.diacetylactis (Str. diacetylactis), Str. thermophilusandLactobacillus bulgaricusin cream prior to conversion into ghee.L. bulgaricusproduced the maximum titratable acidity (1·25% lactic acid) followed byStr. diacetylactis(0·80 % lactic acid) after 72 h.Str. diacetylactisproduced the highest level of diacetyl (28 ppm), after 48 h.L. bulgaricusproduced no detectable diacetyl. Both of these strains produced the maximum amount of volatile acids (2·2–3·5 ml), after 72 h. The flavour and keeping quality of ghee were improved byStr. diacetylactisandStr. lactiswhilstStr. thermophilusandL. bulgaricushad no effect.