Processing of Cereals, Grains

Milling

Wheat, rice, corn, oats: commonly processed cereal grains
De-hulled, ground into smaller pieces or flours
- To improve palatability
- Reduce cooking time
- Create food products

Removes outer hull which contains tough, fibrous material. Grains are revealed; can be toasted, soaked, or cooked to soften and release starch and carbohydrates.

Commodity crops

Corn and soybeans: increasing demand as both animal and human foods; profitable in price
Rice: relatively stable production last 20 years; not a dietary staple in the US
Wheat: spike in prices

But what are commodity crops?

Wheat, Corn, Rice, Oats, Cotton, soybeans
- Can be easily traded
- Stored for a long time
- Grown in large quantities
Example, when you think of cotton you don’t ask where it’s grown or what year it was harvested - it’s just “cotton”. That’s what a commodity crop is

Storage and Distribution

Commodity crops; long shelf life when kept cool and dry
At 70F: dried grains, beans last over 10 years
Minimum energy needed to store products
Since perishability is not an issue, slow, cheap, transportation methods are used

Wheat kernel or seed:

Endosperm: 83% of the grain; typically used in refined bread flower
Bran: Rich in fiber, vitamins & minerals
Germ: vitamins, minerals, fat, protein

Steps in Wheat Milling

Olden days millstones replaced today with rollers
- Separate the bran, germ, and endosperm layers
  - Endosperm layer - starch or flour
Final milling by-product is wheat shorts
- Consist of bran, germ, flour and tailings
  - Used to be for cattle feed only
Now, the bran, germ marketed as “Viable health food”

Fatty acids in germ contribute to off-flavors and rancidity, it is removed; storage time of white flour improved when compared to wheat flour

Bleaching and maturing of flour

*Final stage in the production of white flour
FDA approved use of agents
- Nitrogen trichloride, nitrogen tetroxide, chlorine dioxied, benzyl peroxide, acetone peroxides, azodicarbonamide
WHY?
- Fresh milled, unbleached flour - yellowish due to natral pigments in wheat
- Fresh milled flour - yields small, coarse-textured loaf
Solution: store the flour for several months to lighten color, improve baking qualities
FDA approved agents - similar effects in short period of time
Commerically made white bread, made from bleached flour, was considered a modern food and was more expensive than whole wheat bread
White bread was favored; a status symbol
1920s: wonder bread - with 12 vitamins, minerals - heavily advertised as healthy food for children
Today, whole wheat bread is more expensive than white bread; changing dynamics of food technology, nutrition and science on food choices

Bread production

Ingredient mixing and dough development
Automatic dough slicing and depositing into bread pans/trays
Proofing / second rise
Baking the loaves in hot-air convection oven
Cooling the bread, separating the loaves from the bread pans
Slicing and packaging
Delivery to retail outlets

Products from corn

Sweeteners: glucose, dextrose, corn syrup, high fructose corn syrup
Oils, feed, meal, fiber foods
Modified corn starch: thickeners in foods
Ethanol: fuel and beverage alcohol

Dry milling corn

The dry milling process requires the miller to remove the corn hull and germ without reducing the endosperm
This process produces flaking grits, meals, flours, oil
Breakfast cereal is produced from large flaking grits

Rice

Has traveled from China to India/Pakistan to Africa to Middle East, to Europe, finally arriving in South Carolina
Labor-intensive crop; utilized slave labor
Rice is typically consumed in kernel form
Outside rice hull - inedible; used for fuel or mulch
Brown rice: rice with outer bran layer
White rice: bran removed
**One of the most protected global agricultural commodities

Broken rice

During milling, rice often breaks - broken rice
Not as valuable as unbroken rice; used by processors, cereal manufacturers and pet food manufacturers

Soybeans

The two major products from soybean processing are high-protein meal and oil.
Food uses of oil include shortening, margarine, and cooking and salad oils; nonfood uses include paint, varnish, resins, and plastics
Soybean meal, which is the largest product produced from this process, is used by the feed industry as a protein supplement.
Bean family; primarily used for:
- Livestock feed
- Vegetable oil (80% of oil consumed in US)

Once beans reach the processors

Processed directly into products made from whole soybeans - soymilk, flour, tofu
Further refining: clean, dry, crack the hull form soybean
- Hulls go for animal feed
Remaining portion converted into animal food flakes and soy flour
- Flakes: used to extract soybean oil and lecithin
- Lecithin: widely used emulsifier in salad dressings, mayonnaise, ice cream…

Oats

Steel Cut Oats

Whole grains is cut into several pieces
Longest to cook
Toothsome, chewy texture

Rolled oats

Whole grains first steamed then pressed to flatten them
Cook faster than steel-cut oats

Instant Oats

Most processed
Whole grains pre-cooked, dried, and then rolled and pressed thinner
Cook more quickly