Fiber washing method and system

A method to improve starch yield and/or gluten yield from corn kernels in a wet milling process, comprising the steps of:

• a) soaking the kernels in water to produce soaked kernels;
• b) grinding the soaked kernels;
• c) separating germs from the ground and soaked kernels to produce a corn kernel mass comprising fiber, starch and gluten;
• and
• d) subjecting the resultant corn kernel mass, to a fiber washing procedure;
• wherein during step d) one or more fractions of the corn kernel mass is contacted with an effective amount of one or more hydrolytic enzymes, and wherein the fiber washing procedure is performed with a fiber washing system in a corn kernel wet milling system comprising a plurality of screen units being fluidly connected in a counter current washing configuration from a most upstream screen unit to a most downstream screen unit;
• each screen unit is configured for separating a stream of corn kernel mass and liquid into two fractions:
• a first fraction (s) and a second fraction (f), said second fraction (f) containing a higher amount measured in wt % fiber than the first fraction (s);
• a space (V) is a separate container being fluidly connected with one or more screen units to receive one of said first fraction (s), one of said second fraction (f), or a mixed first and second fraction (s,f), and wherein the space (V) is configured to provide an incubation time in which the first fraction (s), the second fraction (f), or the mixed first and second fraction (s,f) received in the space (V) are contacted with the one or more hydrolytic enzymes to produce incubated fractions;
• and outletting the incubated fractions to a downstream screen unit,
• wherein the system is configured for
• inletting the corn kernel mass and the liquid to the most upstream screen unit,
• outletting the first fraction (s) from the most upstream screen unit as a product stream containing starch,
• inletting process water,
• outletting the second fraction (f) from the most downstream screen unit as a washed corn kernel mass containing a lower amount of starch and gluten than the corn kernel mass, and
• introducing the one or more hydrolytic enzymes into the first fraction (s), the second fraction (f), the mixed first and second fraction (s,f), or the process water, wherein an incubation time in the space (V) is from 0.5 to 3 hours and a total retention time in which one or more fractions of the corn kernel mass is contacted with an effective amount of the one or more hydrolytic enzymes in the fiber-washing system is from 90 minutes to 5 hours.

A wet milling process, which comprises subjecting a corn kernel mass comprising fiber, starch and gluten to a fiber washing procedure in which one or more fractions of the corn kernel mass is contacted with an effective amount of one or more hydrolytic enzymes, and wherein the fiber washing procedure is performed with a fiber washing system in a corn kernel wet milling system comprising a plurality of screen units being fluidly connected in a counter current washing configuration from a most upstream screen unit to a most downstream screen unit;

• each screen unit is configured for separating a stream of said corn kernel mass and liquid into two fractions:
• a first fraction (s) and a second fraction (f), said second fraction (f) containing a higher amount measured in wt % fiber than the first fraction (s);
• a space (V) is a separate container being fluidly connected with one or more screen units to receive one of said first fraction (s), one of said second fraction (f), or a mixed first and second fraction (s,f), and wherein the space (V) is configured to provide an incubation time in which the first fraction (s), the second fraction (f), or the mixed first and second fraction (s,f) received in the space (V) are contacted with the one or more hydrolytic enzymes to produce incubated fractions;
• and outletting the incubated fractions to a downstream screen unit,
• wherein the system is configured for
• inletting the corn kernel mass and the liquid to the most upstream screen unit,
• outletting the first fraction (s) from the most upstream screen unit as a product stream containing starch,
• inletting process water,
• outletting the second fraction (f) from the most downstream screen unit as a washed corn kernel mass containing a lower amount of starch and gluten than the corn kernel mass, and
• introducing the one or more hydrolytic enzymes into the first fraction (s), the second fraction (f), the mixed first and second fraction (s,f), or the process water, wherein an incubation time in the space (V) is from 0.5 to 3 hours and a total retention time in which one or more fractions of the corn kernel mass is contacted with an effective amount of the one or more hydrolytic enzymes in the fiber-washing system is from 90 minutes to 5 hours.