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.