use of nigella sativa oil as a natural preservative agent in processed cheese spread

ABSTRACT

Nigella sativa oil as a natural preservative agent was added at concentrations ratio of 0.1, 0.2 and 0.3% to processed cheese spread. Microbial count, chemical composition, and organoleptic properties of the processed cheese were investigated. The oil used had acid number of 29.5%, saponification value of 176.8% and iodine value of 129.5. Physical properties of the oil were 0.9251 specific gravity, refractive index of 1.472 at 25 degrees, and 0.55 polenske number. The fatty acid composition of the oil were 48.54% linoleic, 38.35% oleic, 13.2% palmitic, 3.25% stearic, 1.9% linolenic and 0.18% myristic acids. Nigella sativa oil had no effect on the chemical properties of processed spread. The treatment of processed cheese spread with sodium bisulfite or Nigella sativa oil at different concentrations led to reduce the microbial groups investigated, the reduction depended upon the concentration of preservative used and the resistance nature of the microbial groups