Decolorization technology of proso millet prolamin

Four methods, including partitioning with toluene and hexane, batch treatment with particle activated carbon, column chromatography on Sephadex G50 and supercritical carbon dioxide fluid extraction with ethanol entrainer were used for decolorizing of proso millet prolamin. The effect of decdorization and protein recoveries of decolorized prolamin product were investigated. Results show that partitioning prolamin with toluene achieves better effect of decolorization and protein recovery. However, the process is too complex and the cost is higher. Procedures of column chromatographic is time-consuming and quantity-limited, so it is restricted in production. Activated carbon give the better results of decolorization and protein recovery, and the trocess is easier and batch samples can be processed simultaneously; Supercritical carbon dioxide fluid extraction with ethanol entrainer shows good decolorization ability and excellent protein recovery, no later process is needed especially. In conclusion, activated carbon and supercritical carbon dioxide fluid extraction are suitable for producing different grades of color-free proteins from proso millet prolamin industrially.