A Method to Use Leuconostoc mesenteroides ssp. cremoris 91404 to Improve Milk Fermentations 1

Abstract

Leuconostoc species are frequently used in mesophilic cultures to produce aroma during milk fermentations. Leuconostoc mesenteroides ssp. cremoris 91404 was selected as an aroma producer in preparation of experimental cultured buttermilk based on low diacetyl reductase activity, citrate utilization and high diacetyl production under acidic conditions, growth characteristics, and compatibility with Lactococcus strains. However, no diacetyl was detected in buttermilk that was made in the traditional commercial manner. Simple and direct GLC analysis without prior processing was applied to quantify volatile compounds in milk that had been fermented with Leu. mesenteroides ssp. cremoris and Lactococcus lactis ssp. cremoris. Fortification of ripened buttermilk with sodium citrate resulted in a significant increase of diacetyl and acetoin production during buttermilk storage (5°C for 2 wk). Surplus of citrate, low pH (pH 4.5 to 4.7), a sufficient number of active nongrowing aroma producers, air incorporation during curd breaking, and low temperature storage facilitated citrate metabolism toward production and conservation of flavor during 2 wk of storage. Incorporation of a ropy Lc. lactis ssp. cremoris strain 352 in starter culture significantly improved the texture and appearance of experimental cultured buttermilk.