Etude du pouvoir technologique de quelques bactéries lactiques du fromage traditionnel Bouhezza.

Abstract

The present study focuses on the study of technological properties of some strains of lactic acid bacteria isolated from the traditional Algerian cheese; Bouhezza Bouhezza is a traditional Algerian cheese known in the east of Algeria (Oum el Bouaghi, Khenchella, Batna, Biskra, etc.…). Its exceptional manufacture is based on the use of a goatskin container with Lben salted and raw cow’s milk during a few weeks. The physicochemical analyses of Bouhezza showed a dry matter between 20,4 ± 0,28 and 30,25 ± 0,60% per one hundred grams of cheese . The pH is between 3,79 ± 0,02 and 4,32 ± 0,05 and the acidity is between 3,51 and 5,79 g of lactic acid per one hundred grams of cheese. The microbial enumerations of the various flora showed the prevalence of the lactic flora presented by the lactobacilli and streptococci with loads of 105 to 107 FCU/g and 105 to 108 FCU/g respectively followed by yeasts and the moulds. The pathogenic flora is absent. The insulation and the purification related to thirty six (36) strains. Nineteen (19) of them made object of the physiological and biochemical identification and the study of the technological capacity. The results indicate the predominance of Lactobacillus genera (41,10%) followed by Leuconostoc (21,05%), Pediococcus (10,52%) and Enterococcus (15,78%). Lactococcus and Bifidobacterium are less significant with 05,26% for each one. The results of the evaluation of technological traits indicate a good acidifying aptitude of Lactobacillus genera (until 67°D) and Pediococcus (65°D), an average acidifying capacity of Leuconostoc (between 30°D and 44°D) and low activity for Enterococcus (25°D). The strains of Lactobacillus have a significant proteolytic capacity (zone of lysis 16 to 18 mm) follow-up by those of Pediococcus genera (15,5 mm) The three other kinds have a similar proteolytic activity ( around 13 mm). The aromatizing capacity, studied by the production of acétoïne, is noticed more in all strains of Lactobacillus genera and differs in the others genus. The study of the antimicrobial activity by the technique of diffusion out of well showed the inhibition of L. monocytogenes ATCC, E. coli (DH5) and B. cereus with strains of Lactobacillus genera. The diameters were between 15 and 30 mm. A less inhibition was obtained with the others genera; Enterococcus, Pediococcus, Lactococcus and Leuconostoc.