High internal phase emulsions stabilized solely by alkali-extracted bamboo leaf polysaccharide conjugates

Abstract

Bamboo leaf polysaccharides have a variety of biological activities, such as antioxidation and immunomodulation, but their emulsifying properties have rarely been involved. In this study, polysaccharide conjugates were extracted from bamboo leaf residue under alkaline conditions, referred to as BLPC- A. BLPC-A aqueous solution and medium-chain triglycerides (MCT) were used as the raw materials to prepare oil-in-water (O/W) high internal phase emulsions (HIPEs). As a single emulsifier, BLPC-A could stabilize 80% (w/w) MCT. With the increase in the BLPC-A concentration (1.00–2.50%, w/w), the average particle size (APS) (d3,2) of the HIPEs gradually decreased, while the viscoelasticity of the HIPEs gradually increased. Furthermore, all HIPEs had good stability during a 30-day storage period at 25 ℃. Among them, after the BLPC-A HIPEs (2.00%, w/w) underwent heat treatment at 40–90 °C, the APS (d3,2) increased from 10.51 µm to 13.01 µm, the tightly packed structure was well maintained, and the HIPEs had good storage stability and enhanced viscoelasticity. When the BLPC-A HIPEs (2.00%, w/w) were exposed to different concentrations of Na+ (0.50–1.00 M) and Ca2+ (0.01–0.05 M), the APS (d3,2) decreased from 8.55 µm to 7.53 µm, and increased from 10.62 µm to 36.54 µm, respectively, while the viscoelasticity was enhanced for each, though HIPEs exposed to Na+ had superior storage stability. These results show that BLPC-A can be used as a natural emulsifier with a good emulsifying effect, while further providing support for the effective utilization of bamboo leaf resources.