Corn Gluten Meal

Wet mills process corn mainly to extract starch. Steeping and grinding also separate the germ, fiber and protein. The protein fraction is dried into a feed ingredient, giving mills another outlet for what they separate.⁴

1. 01 // Source Corn kernels Cleaned corn enters the wet mill before its starch and other kernel components are separated.
2. 02 // Process Steeped and ground Water softens the kernels, and coarse grinding frees the oil-rich germ from the endosperm.
3. 03 // Process Protein separated Screens remove fiber; centrifuging then separates the protein fraction from the starch slurry.
4. 04 // Output Dried protein meal The separated protein is dried into a meal that averages about 90% dry matter as sold.

1. 01

   Raises recipe protein

   At about 67% crude protein on a dry basis, the meal raises a finished food's protein figure without adding meat. Formulators must supply its weaker amino acids elsewhere.⁴

2. 02

   Supplies usable protein

   Dogs digested balanced corn gluten meal diets in controlled trials. That makes it a practical protein ingredient, though digestibility does not fix its lysine and tryptophan gaps.^1,2,4

3. 03

   Uses a milling stream

   Wet mills separate this protein while making starch, and Feedipedia reports that the dried meal is distributed worldwide. Pet food gives that existing stream another buyer.⁴

How much A controlled trial fed 15.3% corn gluten meal in a complete adult dog diet; that tested amount is not a standard recipe amount.²

1. Critics say

   It raises protein without adding meat

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Corn gluten meal averages about 67% crude protein on a dry basis. Adding it raises the crude protein figure through plant protein, so the percentage on a bag cannot tell you how much came from meat.^4,6

2. Brands say

   Dogs digest corn gluten meal well

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A 12-dog crossover trial found the balanced corn gluten meal diet's protein less digestible than the wheat gluten diet's, but more digestible than the chicken by-product meal diet's. The result describes complete foods, not the ingredient alone.¹

3. Brands say

   It makes dogs' stools firmer

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   In a 12-dog comparison, the corn gluten meal diet produced firmer stools than the tested chicken diets, while all groups stayed in an appropriate range. A 10-dog trial also found firmer stools than with a different corn protein.^1,2

4. Brands say

   It replaces meat protein without tradeoffs

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Corn gluten meal is low in lysine and tryptophan. In the 12-dog trial, the chicken diet supplied the strongest amino acid profile without added amino acids. A balanced recipe can use corn protein, but the substitution needs attention.^1,4

5. Owners say

   Corn gluten meal commonly causes food allergies

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Corn was an identified trigger in 13 of 297 dogs with documented food reactions in a research review. That selected group cannot show the rate among all dogs, but it does not support calling corn a common trigger.³