Dried Tomato Pomace

Processors turn ripe tomatoes into juice, paste and ketchup. What the presses and sieves hold back, 1.5 to 10% of the fruit's weight, is wet pomace. Dried, it becomes a feed ingredient.^1,6

1. 01 // Source Ripe tomatoes Whole ripe fruit goes into a juice, paste or ketchup line at a processing plant.
2. 02 // Process Pressed and sieved Juice and pulp move on to become paste. Skins, seeds and some pulp are held back.
3. 03 // Process Dried The wet residue is dried until crisp. Hot air is the cheapest method and destroys the most lycopene.
4. 04 // Output Dried pomace A shelf-stable flake or powder, about 93% dry matter, shipped to feed and pet food plants.

1. 01

   Firms the stool

   Insoluble fiber holds water and adds bulk in the colon. Mink and fox farms add it at 5% of the wet ration to prevent diarrhea. In dogs it acts like other fibers, not better.^1,3

2. 02

   Feeds gut bacteria, a little

   In lab tests with dog fecal bacteria it fermented moderately: more than cranberry or pea fiber, less than apple pomace.^2,4

3. 03

   A waste stream with a use

   Tomato processing leaves 4 to 10 million tonnes of residue a year worldwide. US dog foods used about 4,900 tons of pomace in a year, against 37,500 tons of beet pulp.^6,8

How much A controlled dog trial fed it at 2 and 4% of the diet with no change in intake, body weight or stool, and digestibility stayed above 90%.⁵

1. Brands say

   Adds fiber that keeps stools firm

   Evidence

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

   At about 41% crude fiber the mechanism is real. In a 30-dog trial it lowered digestibility just as beet pulp and wheat bran did, and at 2 to 4% of a diet it left stool unchanged.^1,3,5

2. Brands say

   Prebiotic fiber that feeds good gut bacteria

   Outruns the evidence

   Evidence

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

   The support is mostly test-tube work, where dog fecal bacteria ferment it moderately. One 12-dog trial saw lower fecal pH at 2% but not at 4%. No trial shows it changing a dog's gut health.^2,4,5

3. Brands say

   Lycopene gives dogs antioxidant protection

   Outruns the evidence

   Evidence

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

   Pomace does carry lycopene, 37 to 50 mg per 100 g dry. Hot-air drying destroys much of it, dogs absorb it poorly, and no study has measured a health effect in dogs.^6,7

4. Owners say

   Tomatoes are toxic to dogs

   Outruns the evidence

   Evidence

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

   The toxic compounds sit in the green plant and unripe fruit. Ripe tomatoes are non-toxic, and tomatine is gone by the time fruit is ripe enough to process.^1,9