The bioavailability of nutrients could be improved using in vitro fermentation of hydrolyzed RKB because of the rich carbohydrate contents. Therefore, we hypothesized that in vitro fermentation of enzymatic hydrolyzed RKB will enhance the production of short-chain fatty acids, antioxidant capacity, and minerals in the gastrointestinal tract (GIT). The study's objective was to determine the impact of in vitro fermentation on the bioavailability of nutrients, antioxidants, and short-chain fatty acids in a simulated GIT system. The simulation of the oral, gastric, and intestinal digestion phases was conducted in a bioreactor. The pre-sterilized media prepared was inoculated with pig fecal slurry. The bioreactors were kept in an anaerobic condition at 37°C, agitated at 70 rpm for 24 h. Aliquots were collected, centrifuged, and analyzed for short-chain fatty acids, antioxidants, and minerals. The presence of SCFA (acetic, propionic, and butyric acid) was detected after 24 h in vitro fermentation by Pig fecal colonic microflora with propionic acid having the highest concentration of 47 mg/L using a Gas Chromatography. The total phenolic and total flavonoid contents after in vitro fermentation were 299 mgGAE/100 g DW RKB and 313 mgCE /100 g DW RKB, respectively, without enzymatic hydrolysis. With enzymatic hydrolysis, 265 mgGAE/100 g DW RKB and 215 mg CE/100 g DW RKB, respectively. The P, Mg, Ca, Fe, Zn and Cu were 13997, 801, 634, 75, 18, and 10 μg/kg. This study shows that hydrolyzed RKB has health benefits and can be used in promoting health.