Abstract
Two types of whey protein concentrates were prepared,one from acid whey and the other from sweet whey .These preparations were acetylated and succinylated to various degrees and their functional properties were assessed. Acetylation or succinylation of different whey protein concentrates decreased protein ,lactose and fat,but their total solid and gel strength were increased. Functional properties of sweet and acid whey protein concentrates were more effected by acetylation compared to succinylation. Nine treatments of yoghurt were made to study the effect of fortification of cow milk with acetylated and succinylated whey protein concentrates on the quality of yoghurt at 2 and 4% ratios. Total protein,ash and curd tension ,while whey syneresis decreased by fortification of cow milk with acetylated and succinylated whey protein concentrates through zero,1,3 and 4 days of the storage period. This effect was greater with 4 fortification .Results showed that ash% were higher in the yoghurt fortified with acid whey protein concentrate compared to that of sweet whey protein concentrate. Organoleptic scores of yoghurt fortified with acetylated and succinylated whey protein concentrates to 2.0% were not significantly different from those of the control yoghurt. The yoghurt fortified with 2.0% gained the highest organoleptic scores and was the most acceptable product.
