(Source: Kwong, HK. 2018. Enhanced Antioxidant Activity of Chenopodium formosanum Koidz. Using Lactic Acid Bacteria Fermentation. Master thesis. Institute of Biotechnology, National Taiwan University)         Djulis (Chenopodium formosanun Koidz.) is a traditional crop from the same genus as quinoa (Chenopodiun quinoa), and it is cultivated and consumed as food or wine starter in Taiwan. Reports showed that Djulis exhibits bencficial effects on antinflammation, antidiabetes, antioxidation, and immune regulation. In this study, different probiotics commonly used in the production of fermented dairy products were inoculated independently for Chenopodium formosanum Koidz. fermentation. The strain with the highest antioxidant activity was selected and fermentation process was optimized by using response surface methodology (RSM). Lactobacillus plantarum BCRC 11697 was chosen due to the increased phenolic compounds, DPPH (from 72.6% to 93.2%), and ABTS (from 64.2% to 76.9%) free radical scavenging ability compared to that of other lactic acid bacteria. After applying RSM, the optimal initial fermentation pH, agitation speed, and temperature with highest antioxidant activity (73.5% of DPPH and 93.8% of ABTS) were recognized as pH 5.55, 104 rpin, and 24.4C. Phenolic compounds, DPPH, and ABTS free radical scavenging ability increased significantly during the fermentation process (p ＜ 0.05). The ICso of the DPPH and ABTS free radical scavenging ability were 0.33 and 2.35±0.32 mgml, and both protease and tannase activities increased after RSM. An increase of protein hydrolysates with lower molecular weight (＜24 kDa) were also observed. further