Identification and technological properties of lactic acid bacteria isolated from raw goat milk of four Algerian races Original Research Article

The characteristics of 725 lactic acid bacteria isolated from raw goat milk of four Algerian races were studied. They were phenotypically classified as Lactobacillus (31.6%), Lactococcus (28.4%), Leuconostoc (22.2%), Streptococcus (13.7%) and Pediococcus (4.1%). No major differences were observed as to the distribution of genus isolates in the milk of three races (Makatia, Makatia-Chamia and Kabyle). However, the number of isolates of both Leuconostoc and Lactococcus predominated in Arabia milk while the samples collected from the other races mostly contained lactobacilli isolates. The phenotypic and biochemical analyses gave a diversity of species (28 presumptive species). The most abundant species were Streptococcus thermophilus (46 isolates), Lactobacillus helveticus (45 isolates), Lactobacillus plantarum (30 isolates), Lactobacillus delbruecki subsp. bulgaricus (26 isolates), Lactobacillus brevis (25 isolates) and Lactococcus lactis subsp. lactis (25 isolates). The technological properties of the isolates were as follows: 38.6% of isolates showed a fast acidifying rate (more than 60°D during 18 h of incubation); 25.9% of isolates had a high proteolytic capacity (more than 6 ppm leucine/72 h) and 14.1% of isolates had a high diacetyl production (more than 0.8 ppm diacetyl/16 h). Nine isolates were selected to prepare yoghurt and cheese. Sensory tests performed by a trained panel revealed a pleasant yoghurt prepared with mixed culture St. thermophilus 16 TMC+L. helveticus 20TMC. Cheese prepared with isolates L. lactis subsp. lactis biovar diacetylactis 19 MCA and L. lactis subsp. lactis 10 MCM had a very good sensory quality and a pleasant taste.