Interfacial characteristics and in vitro digestion of emulsion coated by single or mixed natural emulsifiers: lecithin and/or rice glutelin hydrolysates

BACKGROUND The interfacial characteristics and in vitro digestion of emulsion were related to emulsifier type. The mean droplet diameter, zeta-potential, microstructure, interfacial tension, Quartz crystal microbalance with dissipation (QCM-D) and in vitro gastrointestinal fate of emulsions stabilized by soybean lecithin, hydrolyzed rice glutelin (HRG) and their mixture were researched. RESULTS The value of interfacial tension was much more dramatically declined for the sample containing 20 g kg(-1) of HRG. For QCM-D, a rigid layer was formed for all the samples after rinsing. The layer thickness was 0.87 +/- 0.20, 2.11 +/- 0.31 and 2.63 +/- 0.22 nm, and adsorbed mass was 87.17 +/- 10.31, 210.56 +/- 20.12 and 263.09 +/- 23.23 ng cm(-2), for HRG, lecithin and HRG/lecithin, respectively, indicating both HRG and lecithin were adsorbed at the oil-water interface. Structural rearrangements at the interface occurred for HRG/lecithin. The kinetics and final amount of lipid digestion depended on emulsifier type: lecithin > HRG/lecithin > HRG. These differences in digestion rate were primarily due to differences in the aggregation state of the emulsifiers. CONCLUSION The incorporation of lecithin into HRG emulsions had better interfacial properties comparing with HRG emulsion and facilitated lipid digestibility. These results provide important information for the rational design of plant-based functional food. (c) 2021 Society of Chemical Industry.