Processes
The product contained in a bag of feed is the result of multiple processes. There is the pelleting or extrusion process that produced the feed. But there are also other food processes, the by-products of which are ingredients in the feed. This section presents process diagrams to help illustrate how the commercial feed is made, as well as some of the other food processes that generate ingredients used in animal feeds. This is not an exhaustive list of processes, just a sampling of some of the more prominent ones.
Feed Production
Pelleting
Extrusion
Cereal Grain Processing
Wheat
Corn
Oil Seed
Soybean
Rapeseed (Canola)
Cottonseed
Fats and Edible Oils
Feed Production
If grains, oils, vitamin, minerals and other nutrient supplements were simply poured on top of flakes of hay, the horse could simply eat what it found palatable and leave the rest. That would be a wasteful and ineffective way of feeding the horse a nutritionally adequate and balanced diet. Commercial feeds combine the ingredients into a uniform mash and force it through a die to create feed particles that are uniform in size and shape, and in nutrient composition. The two main processes are pelleting and extruding. Both grind and mix ingredients with water to create a mash that is forced through a die. Where the two processes largely differ is in the degree of heat and moisture that is added. The extruding process applies more heat and moisture, and consequently more thoroughly cooks the mash. Cooking results in starches gelatinizing which improves its digestibility and improves the quality of the pelleted. In extrusion, the drop in pressure as the mash exits the die causes the extruded mash to expand. In pelleting, rollers push the mash through holes in a die which results in a densely packed product.
Click on the links below to view the respective diagrams.
Cereal Grain Processing
The object of cereal grain processing is to separate the starch portion (endosperm) of the seed from the outer covering (bran), plant embryo (germ) and, to some degree, the proteins (gluten) that surround the starch. For wheat, the end-product is flour (starch), and for corn the end-products are corn starch (flour) and alcohol (starch converted to alcohol by yeast).
The germ, bran and gluten by-products are further processed into other human food ingredients (e.g. wheat bran, corn oil) or animal feed ingredients (e.g. wheat midds, corn gluten feed).
Click on the links below to view the respective diagrams.
Oil Seed Processing
As the title, “Oil Seed,” suggests, the desired product is oil, vegetable oil. The parts of the seeds that remain after the oil is removed can be further processed into human foods (e.g. soy protein fermented into tofu) or ingredients for animal feeds (e.g. canola seed hulls, soybean meal).
It should also be noted that the oil derived from the oil seed (crude oil) requires additional processing to extract the portion that will show up on store shelves and vegetable oil (see Edible Fats and Oils process diagram).
Click on the links below to view the diagrams.
Edible Fat and Oil Processing
The fats and oils extracted from either animal or plant materials is termed, “crude.” The unprocessed fats and oils contain about 98% triglycerides and free fatty, acid and 2% other compounds such as phosphatides, sterols, tocopherols and tocotrienols (Vitamin E), pigments and fatty alcohols (1). The fat and oil refining process involves removing the “other” compounds and then separating (fractionalization) the remaining triglycerides mixtures into portions that have specific physical and chemical properties (e.g. melting point).
Some of the removed “other” compounds and free fatty acids can be further refined into other edible and non-edible products. Phosphatides can be processed into lecithin products which are used as emulsifiers. The free fatty acids removed from crude fats and oils can be processed into soap.
Click on the link below to view the process diagram.
1. Institute of Shortening and Edible Oils.(2006). Food Fats and Oils (9th Ed.). New York: Institute of Shortening and Edible Oils