EFFECT OF MILK SUPPLEMENTATION WITH VARIOUS TYPES OF MILK PROTEINS ON PHYSICOCHEMICAL AND MICROBIOLOGICAL PROPERTIES OF BIO-FERMENTED CAMEL’S MILK.

In the present work, the influence of milk supplementation on physiochemical, microbiological and sensory properties of probiotic camel s yoghurt during refrigerated storage period of 21 d was studied. Three powders: sodium caseinate (SCN), whey protein concentrate (WPC) and skim milk powder (SMP) at three different ratios (1, 2 and 4%) were tested as supplementation. The results indicated that, the highest (P 0.05) titratable acidity, acetaldehyde and diacetyl values was found in bio-yoghurt supplemented with 4% WPC during storage period. Also, the addition of 4% WPC improved the viability of S. thermophilus, Lb. delbrueckii subsp. bulgaricus, Bifidobacterium animalis subsp. lactis BB-12 and Lb. acidophilus LA-5 more than SCN or SMP bio-yoghurts. On the other hand, the bio-yoghurts fortified with 4% SCN had the highest (P 0.05) viscosity, gel firmness and the lowest whey syneresis values in comparison with other treatments during storage. Organoleptic tests indicate that, the bio-yoghurts fortified with 4% SCN had significantly (P 0.05) higher scores in appearance and body and texture while the bio-yoghurts fortified with 4% WPC had higher acidic taste and flavor scores. Both the bio-yoghurts supplemented with 4% SCN or WPC showed better physical and similar overall acceptability scores compared to other treatments. The results suggested that the addition of 4% SCN or WPC could be used to produce acceptable bio-yoghurt made from camel’s milk.