Optimization of formulation of energetic soft drink containing natural sweetener and whey protein using mixture design-extreme vertices

Production of nutritious drink powders specially based on native or industrial by products is one of the research fields of interests in the food industry. Date syrup as a byproduct of date palm processing is containing a considerable amount of nutritious ingredients and monosaccharides. However this is a little use of this valuable ingredient in the food industry. Whey protein is also one of nutritious and energetic dairy industry byproduct that use of it has been recommended by many food science scientists. In the present study, the effect of concentration of each one of the components include date syrup (0-12%), whey protein concentrate (0-9%) and xanthan stabilizer (0-0/02%) on the phase separation and rheological properties of soft drink by mixture design- extreme vertices were investigated. The results indicated that phase separation deceased with increasing each components specially stabilizer (p<0.05).Generally, increase in components specially stabilizer altered the rheological behavior of soft drink from Newtonian to non-Newtonian.  Also optimization results showed that the phase separation was about 4% in the concentration of 1.49% w/v of xanthan, 8.6% w/v of whey protein and 10.75% w/v date syrup. Optimize formulation had  95 percent of stabilization, consistency index of 0.054 Pa. sn and zeta potential of -34 mV.