QUALITY IMPROVEMENT OF YOGHURT DRINK BY USING SOME MODERN APPLICATIONS : 1- Utilization of Sweet Whey and Some Dried Milk Products in Manufacture of Yoghurt Drink

Yoghurt drink was made using cow s milk yoghurt (control) or yoghurt fortified with skim milk powder (SMP) or milk protein concentrate (MPC) or whey protein concentrate (WPC).The fortification ratios were 0.5%, 1.0%, 1.5% and 2.0% from above materials respectively. The prepared yoghurt mixes were heated to 85◦C/20 min, then cooled to 42◦C to be ready for inoculation with 2% yoghurt starter and incubation at 40◦C until setting. Resultant yoghurt was mixed with15% (w/w) sweet whey well in the blender for homogenization, then cooled in refrigerator at 5+ 2◦C and stored for 12 days. The addition powders had a significant effect on pH and acidity of different yoghurt drink samples .Increasing of milk powders increased T.S, via protein content .The viscosity values were increased as the percentage of additives increased which decreased wheying off since the lowest wheying off was noticed in MPC samples followed by SMP and last for WPC treated samples. Organoleptically, all fresh samples had the best score and accepted for 3 and 6 days of storage.