Optimization of Ultrasound-Assisted Stabilization and Formulation of Almond Milk

Abstract

Almond extract has unique nutritional properties and it can be used as a nutritive beverage. One of the most important problems in the formulation of almond milk is the physical stability of the final product. In this study, the response surface methodology was used to optimize ultrasound (US) treatment and the amount of modified starch, lecithin and agar with respect to physical stability besides other physical properties such as particle size, viscosity, Brix and color attributes. Our results showed that the US treatment had a significant effect on physical responses (p < 0.05). In order to formulate the final product, stabilized almond milk was formulated using a D-Optimal mixture design by considering sensory evaluation. This study suggests using 8.05 sugar, 0.55 stevia and 6.38% rose water to obtain the best formulation. Rheological properties of the formulated milk showed pseudoplastic behavior, and the power law model had the best fitness to the experimental data. Practical Applications One of the most important problems in formulation of the almond milk as a nutritive beverage is the physical stability of the final product. Ultrasonic treatment and addition of various stabilizers can be useful to improve the stabilization of almond milk. The ultrasound treatment and the amount of modified starch, lecithin and agar were optimized with respect to the physical properties using response surface methodology. The best values for the ultrasound time and the amount of lecithin, modified starch and agar were 4.9 min, 0.09, 1.31% and 0.15, respectively. A D-Optimal mixture design was used to optimize the industrial formulation of final beverage by considering sensory evaluation. This study suggests using 8.05 sugar, 0.55 stevia and 6.38% rose water to obtain the best formulation. Rheological properties of the formulated milk showed that pseudoplastic behavior and power law model had the best fitness to the experimental data.