Change in the Penetration Efficiency of Red Ginseng Saponin Extract into Egg White after Cuticle Layer Removal

Abstract

Research has been conducted to enhance the value of eggs by incorporating various functional ingredients. However, it is difficult for functional components with large molecular weights, such as saponins, to penetrate the egg whites. In this study, we sought to improve the penetration efficiency (PE) of red ginseng saponin extract (RGSE) into egg whites after removing the cuticle layer with acid treatment. First, the eggs were immersed in apple cider vinegar for 0, 1, or 2 hours to remove the cuticle layer. Then, the treated eggs were soaked in RGSE solutions of different concentrations (7.41, 14.82, or 22.23 mg/mL) to allow penetration of the RGSE. To assess the effect of removing the cuticle layer on the PE of the RGSE, the saponin content and quality characteristics of the egg whites were analyzed. After staining the cuticle layer of the eggshell with fluorescein isothiocyanate, we confirmed that the distribution of the cuticle layer on the eggshell decreased with increasing acid treatment time using confocal laser scanning microscopy. As the cuticle layer decreased, we confirmed the PE was enhanced because the saponin content in the egg whites increased with the RGSE concentration and penetration time. Moreover, the pH and L* values of the egg whites decreased, the a* value remained constant, and the b* value increased, indicating a change in color due to the RGSE. In conclusion, we have proposed a novel functional egg-processing method by confirming the improved PE of RGSE into the egg whites with cuticle layer removal.