Improving The Properties Of The Egyptian Ras Cheese With Adding Some Probiotic Lactobacillus spp.

Abstract

The objective of the present study was to improve the quality of the Egyptian hard cheese (Ras type) by adding some Lactobacillus spp. as probiotic adjunct cultures. Strains of Lb. acidophilus, Lb. helveticus and Lb. casei were used and the chemical, microbiological and sensory characteristics of the cheese during 90 days of ripening were evaluated. The obtained data indicated that pH values and moisture content were decreased, while the total nitrogen (TN), fat, fat/dry matter, titratable acidity and salt contents were increased significantly during the ripening period in all treatments. For the ripening indices, significantly higher content of soluble nitrogen (SN), SN/TN, soluble tyrosine, soluble tryptophan and total volatile fatty acids were found in the experimental cheese compared to the Control cheese. Higher Lactobacilli count were observed in the adjunct treated cheeses, which reflects the positive retention of Lactobacilli in the experimental cheeses. Also, the use of probiotic adjunct cultures reduced the growth of fungi and prevented the coliform bacteria on Ras cheese. There was higher acceptability for the experimental cheeses than for the Control. Ras cheese was considered a good carrier for Lactobacillus probiotic strains since they were found to survive during cheese manufacture, ripening and storage.