Optimization of the Extraction of Peanut Protein Isolate

Alkali extraction followed by acid precipitation was used to extract peanut protein isolate from defatted peanut powder. The extraction procedure was optimized by response surface methodology (RMS) on the basis of single factor experiments. Extraction time and pH exhibited a significant nonlinear effect on the purity of peanut protein isolate. The optimal extraction conditions were determined to be:extraction time,131 min; extraction temperature,50 ℃; alkali extraction pH,10; and material/liquid ratio,1:12. The purity and yield of peanut protein isolate were 95.05% and 71%,respectively,under the optimized extraction conditions.