The aim of the present study was the isolation of high exopolysaccharide (EPS) producers, Lactic Acid Bacteria (LAB) strains, from three types of milk: goat, sheep, and camel milk. Among 112 LAB isolates tested for their ability to produce EPS on MRS-sucrose agar, only 11 strains were able to produce EPS and only three higher producers’ strains were identified by 16S rRNA gene sequencing as two strains of Lactococcus lactis subsp. lactis (SP255, SP257) isolated from camel milk and one strain of Weissella cibaria (SP213) isolated from goat milk. The physicochemical characterization of the purified EPSs revealed a significant sugar yield, with concentrations ranging from 2.17 to 2.77 g/L, while the protein content remained relatively low (0.03 g/L). The UV-visible spectrum showed high Ultra Violet (UV) absorption at 240–280 nm and the Fourier-Transform Infrared (FTIR) spectra showed the presence of a large number of functional groups, including hydroxyl (-OH), carbonyl (-C=O), and methyl groups (-CH3). The EPS solubility indicated their hydrophilic properties and the investigation of interfacial properties indicated that these EPSs could be used as natural emulsifiers and stabilizers in both acidic and neutral emulsions. Moreover, a new type of emulsion system was developed by the utilization of EPSs in the formation of multilayer interfaces in oil-in-water (O/W) emulsions stabilized by sodium caseinate (CAS). Thus, the impact of an EPS addition on the particle size distribution and electrical charge has been studied. At pH 3, the studied EPSs adhered to the surfaces of caseinate-coated droplets and the stability of O/W emulsions was improved by adding certain concentrations of EPSs. The minimum concentration required to stabilize multilayer emulsions for EPSs SP255, EPS SP257, and EPS SP213 was 1.5, 1.5, and 1.7 g/L, respectively. These findings reveal a new EPS with significant potential for industrial use, particularly as an emulsion stabilizer.

The aim of this study was to compare the physicochemical parameters and the microbiological quality of milk samples of 3 different species in Tunisian arid lands viz. camel, goat and sheep. The results for milk characteristics showed significant differences among the 3 species. Camel milk was the the richest in total proteins (38,6 ± 0.07 g/l), the highest ash content (8,92 g/l±0,49), the most acid pH (pH 6.40±0.03) and the lowest density (1.02±0.2), whereas sheep milk was characterised by the greatest average value dry matter (151,17±2,60 g/l) and the highest fat content (52±0,55 g/l). Likewise, the microbial quality of camel milk was higher than that of sheep and goat milk based on total counts of coliform (TCC), yeast and molds (Y/M) and lactic bacteria (LAB). Although, the microbial analysis of total mesophilic aerobic bacteria (FMAT) revealed an exceeds of standard criteria, suggesting that all samples may contain higher levels of microbial contaminants. To reduce this contamination, several measures must be taken.