| dc.description.abstract | In recent years, Pickering emulsions (PE) and particle-stabilized emulsions
have attracted considerable interest owing to their biocompatibility, tunable
properties, and their ability to resist coalescence. However, the wider application of
inorganic solid particles in food products remains limited primarily because of their
potential adverse effects to human health. In this study, we investigated the use of
generally recognised as safe (GRAS) ZnO nanoparticles and glycerol monostearate
(GMS) as coemulsifiers to fine-tune the stability of red palm oil-based Pickering
emulsions. The emulsion system consisted of red palm oil and water in a 1:1 volume
fraction, with a total emulsifier concentration ranging from 1.5-5% and ratios of
1:2, 1:1, and 2:1 between ZnO and glycerol monostearate. The effects of total
emulsifier concentration and ratio on the properties of the emulsions were analysed.
An increase in the total emulsifier concentration had a positive effect on the
physical (static) stability of the emulsions. The chemical stability of red palm oil
increased with increasing emulsifier concentration, as indicated by the flattening
slope of the free fatty acid and carotenoid content. However, the difference in
emulsifier ratio did not show a significant effect. Based on the rheological
characterization, the emulsion system was categorised as a shear-thinning fluid with
viscoelastic properties. The results indicated that increases in the total emulsifier
concentration and GMS ratio were negatively correlated with the rheological
stability of the emulsion, as demonstrated by hysteresis. Every emulsion prepared
in this study showed unique properties, ranging from flowable to thick and
margarine-like consistency. This study provides a new perspective for the
formulation of emulsions using solid particles and molecular co-emulsifiers in
food-grade Pickering emulsion systems. | |
