GB651403A - Improvements in and relating to the preparation of zein - Google Patents

Abstract

<PICT:0651403/IV (b)/1> In a process for the extraction of zein, maize gluten is subjected to a treatment with an aliphatic chlorhydrocarbon at above room temperature whereby the major portion of the impurities is dissolved out, and the purified oil-free maize gluten is then treated to extract the zein. The gluten need not be dried before extraction and water may be removed in the treatment with the chlorhydrocarbon. Maize gluten as a suspension in water or substantially free from water may be used, a starch-free gluten being preferred. The impurities dissolved in the chlorhydrocarbon may be continuously removed from the heated zone. In an example, maize gluten is agitated and boiled with trichloroethylene, in vessel 1, the rising vapours of the latter and entrained water being condensed in condenser 10, the water separated from the trichloroethylene in separator 11, which is then refluxed to vessel 1. A solution of impurities in trichloroethylene passes through the streamline filter 7 into container 13 and thence to vessel 17 where the trichloroethylene is distilled and returned via pipe 18 and the reflux system. Water and trichloroethylene are then removed via the separator and valve 91. The purified gluten is heated with aqueous alcohol and the zein solution is separated in a centrifuge or by decantation. Removal of residual trichloroethylene from the gluten may be expedited by blowing in live steam with or without the application of a vacuum. Alcohol distilled from the zein solution may be returned to vessel 1. Suitable chlorinated solvents are trichloroethylene, perchloroethylene, carbon tetrachloride, ethylene dichloride, acetylene tetrachloride, trichlorethane propylene dichloride. In the second stage aqueous alcohol and solvents such as methanol, aqueous isopropyl alcohol, aqueous acetone, a binary mixture of two of the following, an alcohol, a chlorinated hydrocarbon, an ether, an ester or water, or known ternary solvent mixtures may be used. The zein solution may be decolourized as described in Specification 651,396.