CREAM FERMENTATION BY A MIXED CULTURE OF LACTOCOCCI ENTRAPPED IN 2-LAYER CALCIUM ALGINATE GEL BEADS

This investigation was directed towards the development of a process which produces a fermented cream of greatly reduced cell number. Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. lactis biovar diacetylactis were entrapped separately in normal or two-layer Ca-alginate gel beads. Pasteurized cream (31% fat content) was inoculated with free-cells and with normal or two-layer beads. When 8% of the total volume was occupied by the gel, there was 300-800 times more inoculum in this system and the fermentation time was considerably reduced (5h against 18h). When pH 5.0 was reached, the residual free-cell count was 150 and 1800 times less than for a classical inoculation method with free-cells for normal and two-layer beads respectively. This result was reproducible for several consecutive runs. Also, the problems linked to storage acidification (souring, wheying-off) appeared later and living lactic acid bacteria were maintained in the product.