Generation and Influence of Carbon Dioxide Nanobubbles on Physicochemical Properties Including the Surface Tension of Clarified Apple Juice

Abstract

This work aims at examining the impact of generated CO2 nanobubbles (NBs) via the membrane-based method on physicochemical properties and surface tension of commercial clarified apple juice. The gas was injected at 300 kPa pressure for variable liquid circulation times (5, 13 and 26 min) to produce the CO2 NBs. Sets of 13- and 26-min circulation time to mix CO2 and liquid gave the desirably nano-size (~ 80–200 nm) NBs and significantly (p ≤ 0.05) reduced surface tension (by ~ 20–25%) of the juice dispersed with these formed tiny gas bubbles (NB-juice). An increase in circulation time also resulted in more negative zeta potential and higher dissolved CO2 concentration of the NB-juice. Density values of apple juice remained unchanged with and without incorporating CO2 NBs. These experimental outcomes provide the potential use of NBs in controlling the characteristics of liquid food as an environment-friendly approach to minimise chemical usages.