Natural oil emulsions stabilized by β-glucan gel

Abstract

Many foods and cosmetic products are applied in gel form that offers convenience to the consumers. In this work, we demonstrate a novel use of β-glucan (BG) isolated from Pleurotus ostreatus as a functional ingredient in food, cosmetics, and as a food additive. Stable emulsion gels were prepared by homogenization of BG hydrogel containing from 0.10 to 2.0wt.% BG with natural oil without a cosolvent or surfactant addition. The oils, chosen as representative commercial beneficial fats, were conjugated linoleic acid (CLA), coconut oil, olive oil, and cocoa butter. Formulations containing from 10 to 50wt.% of oil in BG gel exhibited stability for more than 12 months. Moreover, stable Pickering-type emulsions were prepared by adding micronized BG particles to 0.05wt.% BG hydrogel. The emulsion gels were characterized visually, SEM, cryo-electron microscopy, and viscosity measurements. The oil droplets are trapped and held in place by viscous BG hydrogel network structure created through interacting chain segment association and aggregated junction zones. Presence of crystalline cocoa butter in emulsion gels was confirmed by DSC and XRPD. The study of the water mobility within the xerogels using the dynamic vapor sorption technique showed that cocoa butter loading of 69 % resulted in a reduction of equilibrium moisture content and hysteresis. The emulsion gels prepared show promising functional stability for emulsion-type cosmetics and as suitable carriers for dermal application.