Effect of vacuum alteration of oat - water mixture on physical stability and physicochemical properties of oat-based beverage: Multi-response optimization study

Exploring new processes can help to deal with physical instability of oat based beverages (OBB) which occupies an important position in the ever-expanding traditional and non-traditional milk and dairy products market. Physical instability during storage and sales negatively impacts consumer perception, thereby reducing the desirability of the product. In this study, vacuum alteration was performed to overcome the physical instability. The multi-response optimization study, with the responses of index of viscosity, physical stability and zeta potential, was carried out to determine optimal oat concentration (C-oat), atmospheric pressure holding duration (t(atm)), vacuum pressure (P-vacuum), and vacuum holding duration (t(vacuum)) parameters. To obtain beverage like consistency with high physical stability, index of viscosity was minimized and physical stability and zeta potential were maximized. According to that, two optimal points were determined as Opt1 (t(atm) = 5 min, P-vacuum = -70 kPa, t(vacuum) = 10 min and C-oat = 15 %) and Opt2 (P-vacuum = -90 kPa, t(atm) = 20 min and C-oat = 15 %). Conventional OBB which was produced using enzymatic hydrolysis named as control. An enhancement in physical stability and zeta potential was observed for the optimal OBBs in comparison to the control (p < 0.05). Index of viscosity of optimal OBBs was comparable with control and two industrial OBBs (p > 0.05). On dry basis, optimal OBBs had similar protein content with lower total carbohydrate content along with higher particle size and yield compared to control. Vacuum alteration has the potential to serve as an alternative OBB production step, eliminating grinding or homogenization processes. This study provides significant outcomes, enhancing physical stability without the need for additives.