Modulating the stability and rheological behavior of camellia oil body emulsions via pH regulation and different charged polysaccharide coatings.

Abstract

This study investigated the effects of chitosan (CTS), sodium alginate (SA), and methylcellulose (MC) on the physicochemical stability and rheological properties of camellia oil body (OB) emulsions across pH 3.0-9.0. A zeta-potential-derived charge descriptor was used to identify representative pH conditions (3.0, 4.5, 7.0, and 9.0) for further characterization. Uncoated OB emulsions showed pronounced destabilization near the isoelectric region, with particle sizes increasing to approximately 5000 nm at pH 4.5. CTS-coated emulsions showed improved dispersion under acidic conditions, maintaining particle sizes of approximately 1300-1800 nm, but exhibited increased aggregation at neutral and alkaline pH. SA-coated emulsions showed distinct pH-dependent stability and rheological responses, including high apparent viscosity (14.2 Pa.s) under acidic conditions. MC-coated emulsions exhibited comparatively low apparent viscosity across the tested pH range. Overall, these findings revealed distinct polysaccharide-dependent responses, providing comparative insights into the regulation of OB-emulsion properties under different pH and processing conditions.