Effect of sodium caseinate, whey protein concentrate and carboxymethylcellulose on fat droplet size and gravitational separation in salad dressing

Response surface methodology (RSM) was used to evaluate the effects of whey protein concentrate، X1، (0. 7-2. 8 % w/w) and caseinsodium، X2، (0. 7-2. 8 % w/w) as a substitute for eggs، and carboxymethylcellulose، X3، (0. 66-0. 234 % w/w) as thickening agent in salad dressing on the stability and particle size of salad dressing. The central composite experimental design was used and the data were analyzed using RSM. The results of analysis of variance (ANOVA) showed that P values of all models were significant and lack of fit P values was no significant at the level of 95%. Therefore، the adequacy of models was acceptable. From the empirical models obtained by RSM in this study، the optimal values of independent variables for the stability of the salad dressing were obtained: 1. 68% for whey protein concentrate، 1. 68% for sodiumcaseinate، 0. 168% for carboxymethylcellulose (% w/w). Based on the results، the optimum level of these variables with the lowest fat droplet size was: 2. 8% for whey protein concentrate، 2. 8% for caseinsodium، 0. 234% for carboxymethylcellulose. The results indicated that using whey protein concentrate، sodiumcaseinate and carboxymethylcellulose reduced oil droplet size and increased stability during centrifugation in salad dressing. Therefore، milk proteins can be used as a substitute for eggs in salad dressings.