Emulsifying Properties of Ethanol-Precipitated Mucilage From Cellulase-Hydrolyzed Green Algae (Monostroma Nitidum)

Abstract

The emulsifying properties of the ethanol‐precipitated mucilage from cellulase‐hydrolyzed Monostroma nitidum were investigated. Both emulsifying activity and emulsion stability of the mucilage increased from 51.5 and 48.0% to 69.0 and 62.0%, respectively, and oil droplets did not coalesce when the mucilage concentration was at l%(w/v). Gel permeation chromatography showed that the carbohydrate moieties of the mucilage exhibited an absence of low molecular weight fractions and a broader molecular weight range for the high molecular weight fraction than that of the cellulase hydrolysate. Also, there was a greater amount of high molecular weight protein‐containing fractions in the mucilage, while predominantly low molecular weight protein fractions were in the hydrolysate. Increasing the mucilage concentration of the solution(0–20 mg/mL) led to a reduction of surface tension to 54.9 dyne/cm, and increased the emulsifying activity and emulsion stability to 76.9 and 70.0%, respectively. The oil did not separate from the emulsion when the mucilage concentration was higher than 0.5%(w/v). When 0.2% NaCl was added to the emulsion containing 1% mucilage, the apparent viscosity decreased from 37.1 to 7.6 Pa.s (x 10‐3). Also, the emulsifying activity and emulsion stability decreased from 69.0 and 62.0% to 50.0 and 48.0%, respectively.