Confirmation and understanding the potential emulsifying characterization of persimmon pectin: From structural to diverse rheological aspects

In the study, the structure properties of persimmon pectin (PP) affecting the interfacial performance were characterized firstly. Then, the interfacial behavior of PP at the oil-water interface was evaluated by interfacial tension and interfacial shear/dilatational rheology. Further, the emulsifying and emulsion stabilizing capability of PP were explored based on structure elucidation and interfacial characterization. Structural elucidation of PP indicated that structural characteristics, including high-methylated (71.93 ± 1.23%), lower Mw (4.789 × 104 g/mol), and abundant hydrophobic substances including acetyl-groups (1.21 ± 0.09%), protein (11.54 ± 0.75 mg/g), and ferulic-acid moieties (2.47 ± 0.13 mg/g), contributed to its rapid adsorption to the oil-water interface. Additionally, PP was rich in both homogalacturonan (62.42 ± 1.12%) and rhamnogalacturonan-I (17.75 ± 0.48%) domains, favoring it adsorbed at the oil-water interface. Of all tested emulsifier solutions (1.0%–3.0%, w/v), PP exhibited potent tension-lowering capacity. Additionally, a strong viscoelastic layer of PP (1.0%, w/v) was formed at the oil-water interface based on the interfacial shear (interfacial adsorption and dynamic strain sweep) and interfacial dilatational rheology (interfacial viscoelasticity, frequency and amplitude sweep). Notably, PP exhibited promising emulsifying and emulsion-stabilizing potential, as reflected by small droplet size, creaming thickness (0.68 ± 0.00 mm), and high emulsifying capacity (63.22 ± 1.58%), turbidity (0.37 ± 0.00), etc. By using multi-techniques and multi-scale analysis, the present work effectively correlated the interfacial, structural, droplet characteristics, and bulk emulsion of PP. Results suggested that PP exhibited a promising emulsification potential and could be developed as a novel polysaccharide emulsifier in the food industry.