Abstract
Red ginseng extract is one of the most widely used herbal medicines to prevent and cure various diseases. Among the processed products derived from red ginseng, the water-insoluble part as red ginseng residual (RGR) becomes waste, even though it contains important ingredients. TEMPO-oxidation (TO) can be used as a pre-treatment with different degrees of oxidation (DO) (0 to 0.4) in red ginseng residual (RGR-TO) by introducing chemical oxidation and high-pressure homogenizer (HPH) as a nanofibrillation process. 1H NMR was used to determine the carbohydrate composition and calculate DO, size was examined using a nanoparticle analyzer, and the zeta potential was used to determine surface charge density. RGR-TO with different concentrations had different compositions; glucose and uronic acid were the main ingredients. All treated RGR-TO showed higher oxidant levels than the untreated counterpart (RGR-TO 0). As the oxidant levels increased, the zeta potential and uronic acid increased, but the size of the nanofibril from RGR-TO decreased. The results of this study showed that TEMPO-oxidation pretreatment was effective in producing RGR cellulose nanofibril (CNF) with a variety of properties by adjusting the level of oxidation pretreatment and the number of HPH passes.