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.

Opuntia is a cactus with fruits and is also called prickly pear. Extraction process of water soluble fiber from opuntia stem powder was optimized by applying various conditions such as ethanol concentration, temperature and pH. Fiber extraction was highest in 0% ethanol and lowest in 100% ethanol, indicated that hot distilled water extraction produced maximum water soluble fiber. Among temperature range from 50 to 90°C, water soluble fiber was extracted mostly at 50°C and leastly at 90°C, showing decrease in fiber with increase in temperature. On the other hand, pH higher than 7 did not show any significant difference in fiber extraction, while fiber extraction decreased in lower pH 7. Conclusively ethanol hampered extraction of water soluble fiber from opuntia stem powder and extraction was not stable with higher heat and low acidic condition.