Technology for the extraction of protein from grain amaranth

To study the technology for the extraction of protein from grain amaranth, the effect of pH value, extracting time, extracting temperature and the ratio of extracting medium were studied. The amino acid profile of extracted protein at three pH values was analyzed by the HPLC. The results showed that pH value greatly influenced the solubility; and a minimum solubility was found at pH 4.6. The solubility decseased as pH value increased at pH 2.0～4.6, while the solubility increased as pH value increased at pH 4.6～12.0. High protein solubility was found at a 20∶1 ratio of water to Amaranth. It was observed that other factors did not significantly affect the solubility of the protein. Based on the primary results, extracting 1 h at room temperature, a 20∶1 ratio of water to amaranth and pH 8～10 may be the best technology for the extraction of protein from grain amaranth.