Optimization of process variables for the preparation of oat milk using the Box–Behnken response surface model and studying the effect of enzyme hydrolysis on structural and thermal properties of oat starch

Lactose intolerance and the growing number of vegan and plant-based lifestyles are the main causes of the growing popularity of dairy substitutes, including sesame, soy, almond, coconut, cashew, oat, and peanut milk. Oat milk, a popular alternative, is created by blending oats with water. Many individuals highly favor this plant-based beverage due to its milk-like taste and its provision of essential nutrients. An oat milk substitute has been developed through the enzymatic hydrolysis process utilizing alpha-amylase. The Box–Behnken design of response surface methodology (RSM) was used to investigate the combined impact of the enzyme concentration (2–10% v/w), oat slurry concentration (10–15% w/w), and liquefaction time (15–45 mins). The optimization of process parameters was conducted by considering many criteria including yield %, viscosity, total soluble solids, total solids, zeta-potential, and particle size. The optimized oat milk is also compared to traditionally prepared raw oat milk to analyze the structural and thermal alterations in starch following enzymatic treatment. An investigation was conducted to examine the disparities in the subjects’ structural characteristics, physicochemical attributes, and thermal properties. The XRD, DSC, and FTIR analyses revealed that the oat milk exhibited significantly higher relative crystallinity, and a more organized and stable double-helix structure, compared to the untreated raw oat milk.