Abstract: Two extraction methods, namely alkaline method and salt method were used to extract protein from Job  s Tears seeds, and their effects on the extraction rate of protein from Job s Tears seed were compared. In the alkaline extraction method, the extraction parameters pH, material-to-liquid ratio, temperature and extraction time were optimized by single factor and orthogonal array design methods based on the extraction rate of protein from Job s Tears seed. The extraction parameters optimized (also by single factor and orthogonal array design methods) in the salt extraction method were salt concentration, material-to-liquid ratio, temperature and extraction time. The results showed that the optimum material-to-liquid ratio, temperature, extraction time and pH for the alkaline extraction of Job s Tears seed protein were 1:12, 35 ℃, 5 h and 11, respectively. Under these conditions, the extraction rate of protein was up to 43.56%. Overall, the alkaline extraction method was superior to the salt extraction method.

Key words: Job s Tears seed, protein, extraction