Modeling of flow behavior and rheological properties and formulation optimization of ice cream using RSM

Ice cream is a complex food colloid including fat droplet and air cells that dispersed on the relatively frosted aqueous phase. In this research work, the effect of the fat at the four level ( 2.5, 5, 7.5, 10 % ) , pekmez at the three level ( 0, 9, 18 %) , two types of hydrocolloids (Carboxyl Methyl Cellulose and balangu ) each at the four level ( 0.1, 0.3 ,0 .5 , 0.7 % ) on the viscous flow properties and total acceptance of ice cream by response surface methodology (RSM) was investigated. The flow behavior of all samples using Power law, Casson, Bingham and Herschel- Bulkley models was investigated. According to the R² (≥0.99) and RMSE (≤0.9314) values, it is obvious that the Power law model is highly appreciated for describe flow behavior of ice cream samples. Also the Result indicated that casson plastic model was highly significant for evaluate yield stress of ice cream samples. Samples containing Balangu gum has higher consistency coefficient and yield stress and lower flow behavior index than samples containing CMC. Its worth to mention that Herschel-Bulkley model gave negative values for yield stress which has no physical meaning. Balangu seed gum (BSG) in comparison to carboxyl methyl cellulose did not have a significant effect (P > 0.05) on the total acceptance. The Desirability function has been achieved as 0.93 which, itself, indicates the accuracy of optimization. The optimum formulation has been found as following: fat of 5.6%, BSG of 0.6% , Pekmez of 18%, respectively.