US 4,286,058 AGranted

Enzymatic conversion of high moisture shear extruded and gelatinized grain material

AssigneeWenger Manufacturing, Inc.

InventorsLavon G. Wenger, Galen J. Rokey, Itamar Ben-Gera

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Abstract

Methods and apparatus for high-moisture extrusion of starch-bearing grains is disclosed which yield cooked, gelatinized products suitable for short-time enzymatic conversion to sugars, and particularly those subject to fermentation to alcohol; the high production rates afforded through use of extrusion equipment, and the short conversion time of the resultant products, is particularly advantageous for economical alcohol manufacture, both for alcoholic beverages and for use as fuel. Preferably, whole or cracked starch-bearing grain is presoaked in an excess of water to a substantial moisture level, and the resultant slurry is fed to a specialized extruder. In the extruder the water is at least partially separated and carried from the process, and the grain is highly cooked and gelatinized for subsequent conversion. The overall apparatus preferably includes presoak tanks for the grain, a grain-conveying feeder, an extrusion cooker, and enzyme conversion tanks; the apparatus is advantageously sized for batch-continuous operations to produce a continuous flow of sugars. Conversion times for the gelatinized starches are low, less than about 45 minutes, and moisture and extrusion conditions can be altered to further lower sugar conversion time.

Claims11

Dependent claims

A method of producing sugars from a starch-bearing material, comprising the steps of:

providing a quantity of a starch-bearing grain material;
soaking said material in an aqueous medium, said aqueous medium being present at a level of at least about 100%, based upon the weight of said material taken as 100%, until said material is substantially permeated with said aqueous medium and moisturized to a level of at least about 80% of the saturation level of the material;
passing said permeated and moisturized wet material into the inlet of the barrel of an elongated extruder equipped with a rotatable material-conveying screw and an apertured, flow-restricting extrusion die plate;
rotating said screw in order to move said wet material along the length of said barrel, subjecting said wet material to elevated temperatures and pressures during passage thereof along the length of said barrel, and subjecting said wet material to mechanical shear and passing the wet material through the aperture of said die plate to gelatinize at least about 95% of the gelatinizable fraction of the wet material passed through said aperture and give at least a portion of the gelatinized material a conversion time of no more than about 45 minutes;
and
adding an enzyme to said gelatinized material without drying of the gelatinized material to convert at least a portion of the gelatinized material to said sugars.

3 more elements

Dependencies are inferred from the claim text.