The purpose of this study is to optimize the extraction conditions (time, pH, and temperature) for water-soluble dietary fiber (SDF) and solids from Opuntia ficus-indica (OFI) stems and to evaluate the functionality of the optimized extract. The maximum extraction yield was obtained when 100% distilled water was used, indicating that ethanol hampered the extraction. The extraction yields were lower at higher temperatures and lower pHs. The maximum extraction of SDF (27.92%) and solids (5.6 g) was achieved with a 7-h extraction at 50oC and pH 7.0, with desirability being 0.958. The stem extract obtained under the optimum extraction conditions had an antioxidant capacity of 118.10 mg vitamin C equivalents (VCE) using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. In a medium containing 30% extract, the growth of E. coli was reduced by 34%, while that of B. cereus was reduced by 23%. These results suggest that OFI stems can be used as a functional resource.

The purpose of this study was to utilize the stem of Opuntia ficus-indica and to optimize the extraction conditions and standardize extract process for water soluble dietary fiber and solid. Extraction process was optimized by applying various conditions such as pH, ethanol concentration, extracting temperature and time. Maximum extraction yield for water soluble dietary fiber and solid were obtained using 100% water, indicating that ethanol hampered extraction. Also, extraction was unstable with higher heat, longer extraction time, and low acidic conditions. Maximum extraction of water soluble dietary fiber (27.92%) and solid (5.6 g) were obtained at 50°C, pH7, and 7 hr extraction time. Extract had antioxidant capacity at 1105.98 mg vitamin C equivalents (VCE) on ABTS assay and 118.10 mg VCE on DPPH assay.