Development of a continuous membrane nanobubble generation method applicable in liquid food processing

Abstract

SummaryA novel continuous nanobubble generation method was developed using a commercial ceramic membrane as a nanobubble generator. CO2 and air were infused externally across the ceramic membrane (pore size 50 nm) into the water flowing inside the ceramic membrane tube. Infusion of each gas was done in a single (20 s) and multiple passes (180 s) at 20–21°C. Results showed that gaseous nanobubbles could be generated even in a single pass. Low power ultrasound (200 kHz, 30W) was applied for the rapid assessment of nanobubble stability. Single‐pass ultrasound treatment of the samples was carried out at two levels: 2.6 and 5.1 J mL−1. Among the samples in which gases were infused for multiple passes, air nanobubbles were found more stable than CO2. In contrast, an opposite trend was observed in those samples in which gases were infused in the single‐pass only (20 s). This process has the potential to be applied to food processing industries, such as to enhance the products’ sensory attributes, the efficiency of membrane separation, food drying and liquid food transportation systems.