Continuous-flow versus batch ultrasonication: efficient, scalable modification of pregelatinized rice flour

Rice flour is widely used in dairy alternatives like rice milk, but poor solubility and dispersibility in aqueous systems limit its broader application. While batch-type ultrasonication can enhance these properties, scalability remains limited. We investigated continuous-flow ultrasonication effects on solubility and physicochemical properties of pregelatinized rice flour versus batch-type sonication. Rice flour suspensions (8–16 %, w/w) were pregelatinized and sonicated using a continuous-flow system for 10–40 min. For comparison, samples were treated in a batch-type system for 15 min. Physicochemical properties were evaluated based on hydration properties, pasting behavior, and rheological characteristics. Microstructural changes were analyzed using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM). Continuous sonication improved water solubility and reduced apparent viscosity of pregelatinized rice flour across concentrations. Sonication caused amorphization of the starch structure and modified protein secondary structure ratios, with SEM images showing surface erosion and particle breakdown. Critically, while both methods produced comparable rheological endpoints, the continuous system demonstrated a ∼3.8-fold higher throughput than the batch process, highlighting its superior industrial scalability. These findings indicate that continuous ultrasonication is a more efficient and scalable method for producing rice flour with improved properties suitable for rice-based beverage formulations. • Continuous-flow ultrasonication efficiently modifies pregelatinized rice flour. • It improves water solubility and reduces RVA pasting parameters. • The continuous process showed ∼3.8-fold higher throughput than the batch process. • Ultrasonication induced starch amorphization and altered protein secondary structures. • Continuous processing is a scalable alternative to batch for industrial applications.