Application of NaOH-HCl-Modified Apple Pomace to Binding Epigallocatechin Gallate

NaOH-HCl-modified apple pomace was prepared in order to increase the adsorption capacity for epigallocatechin gallate (EGCg). The modified apple pomace contained 408.2 mg g −1 dietary fiber, 57.7 mg g −1 lignin, 23.2 mg g −1 protein, and 9.0 mg g −1 pectin, and the features of the apple pomace materials were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The adsorption of EGCg onto modified apple pomace showed excellent fitness with the pseudo-second-order model, suggesting that chemisorption was the rate-controlling step. The isothermal adsorption studies were carried out over a range of concentrations (25–1000 mg L −1 ) and temperatures (20, 30, and 40 °C). Low temperature advanced the adsorption capacity for EGCg. Both the Langmuir and Freundlich models precisely described the isothermal adsorption of EGCg onto modified apple pomace. Thermodynamics showed that this adsorption process was endothermic and spontaneous. Our study highlights that NaOH-HCl-modified apple pomace has good adsorption characteristics for EGCg, which could be a promising candidate for EGCg delivery in functional food and dietary supplement applications.