Development of a novel microemulsion towards improved stability of Zanthoxylum piasezkii Maxim. oleoresin

Abstract

Poor storage stability of Zanthoxylum piasezkii Maxim. oleoresin (Z. piasezkii. oleoresin), a viscous fluid extracted from Zanthoxylum piasezkii Maxim. has limited its utilization in downstream products. The formation of microemulsion (ME) was expected as an ideal protocol for enhanced storage stability of Z. piasezkii. oleoresin, which was developed using polyethylene glycol 400 dioleate (PEG400DO) as surfactant and 1,2-propylene glycol (1,2-PG) as cosurfactant. An improvement in ME area, viscosity, and surface tension was found in one system compared to other formulations, with 37.54% of microemulsion formation area, a viscosity value of 242.17 mPa.s, and surface tension of 29.75 mN/m. This ME consisted of 40 wt% essential oil, 1.59 wt% surfactant mixture (3:1 (m:m) of 1,2-PG and PEG400DO), and 58.41 wt% Z. piasezkii. oleoresin. Additionally, this system exhibits steady performance, demonstrating the potential of a blend of surfactants-based ME as stable system for the utilization of Z. piasezkii. oleoresin as savory flavor.