Microbial, chemical and rheological properfies of laban (cultured milk)

The chemical, microbial and rheological properties of commercial and home-made laban were investigated in an effort to contribute to the standardization of the product. Commercial laban has higher fat, protein and total solids content but was less acidic than traditional laban. Lactobacilli dominate in the former, whereas lactococci are found mainly in the latter. Four micro-organisms classified as Lactococcus lactis ssp lactis, Lactococcus lactis ssp lactis biovar diacetylactis, Lactococcus lactis ssp cremoris and Lactobacillus plantarum were responsible for the fermentation of traditional laban, whereas three micro-organisms, namely: Lactobacillus acidophilus, bifidobacteria and Streptococcus thermophilus were responsible for the production of commercial laban. Unlike the commercial preparation, traditional laban contained considerable numbers of yeasts and moulds and was contaminated with coliforms and fecal coliforms. The rheological profile of a semi-dilute solution was more pronounced in the home-made laban with both preparations flowing from the first Newtonian plateau and the power law region to the second Newtonian plateau with increasing shear rate.