Module 8- corn processing and products

Question 1

how is most corn processed

Answer 1

Most corn is processed by wet milling the grain

Question 2

what is wet milling

Answer 2

Wet milling uses water in the grinding process to effect a separation of the starch, fibre, protein and soluble components of the grains

Question 3

what is wet-milled food used for

Answer 3

Wet milled corn products are used in a wide variety of feed, food and industrial applications.

Question 4

what is the process of wet milling

Answer 4

The process begins with a thorough cleaning of the incoming material followed by steeping or soaking in water that contains a trace of sulphur dioxide. The corn is steeped for 1.5 to 2 days at 50°C to soften the grain and increase the moisture content to 45 to 50 percent. The sulfur dioxide inhibits bacterial growth and begins the breakdown of the protein in the starchy endosperm. The pre-soaked grain is then shredded in a degerminating mill to separate the oil-rich germ from the starchy endosperm. The germ is collected by density separation, dried and removed for oil extraction. A high quality protein meal is produced from the germ after the oil is extracted. The degermed grain is ground very fine in a wet milling system and screened to remove bran and endosperm cell wall fibre. The resulting starch-protein milk is separated into solid (starch) and liquid (protein, sugars, etc.) fractions by centrifugation. The starch is further refined by washing and drying yielding a very refined starch product. The soluble liquid fraction is a by-product that usually enters the livestock feed chain

Question 5

what are the steps of corn milling

Answer 5

1) cleaning
2) steeping
3) degermination
4) milling
5) screening
6) centrifusion
7) cleaning

Question 6

what comes out of the steeping process of wet milling

Answer 6

steepwater

Question 7

what comes out of degermination of went milling

Answer 7

the germ

Question 8

what comes out of the screening process of wet milling

Answer 8

fiber

Question 9

what comes out of the centrifugation process of wet milling

Answer 9

protein and starch

Question 10

what is dry milling of corn used for

Answer 10

Dry milling of corn is used to produce bran, germ, grits, meal and flour

Question 11

when is corn bran and germ removed for roller milling

Answer 11

Corn bran and germ are removed prior to roller milling

Question 12

what is the bran used for from roller milling

Answer 12

The bran is used for human consumption and in livestock feeds

Question 13

what is the germ used for from roller milling

Answer 13

The germ is used for the production of corn oil and cornmeal

Question 14

what are the grits, flour and starchy endosperm from roller milling used for

Answer 14

Grits, flour and meal from the starchy endosperm are used in the production of snack foods, tortillas, chapattis, ready-to-eat breakfast cereals, brewing and distilling and the production of grain alcohol

Question 15

is roller milling corn like roller milling wheat

Answer 15

Roller milling corn requires some modifications relative to the process used for wheat because of the large germ and the different end-products being collected

Question 16

explain the process of corn milling

Answer 16

Corn milling begins with a degermination step during which the moisture level is raised to approximately twenty percent and the kernels are torn open to expose the germ. Following degermination, the process is essentially the same as that used for wheat; a gradual reduction in particle size and separation of bran, germ and starchy endosperm as discrete fractions. Dry milling improves palatability, digestibility and functionality of the grains

Question 17

what kind of corn is mostly milled

Answer 17

Most of the corn milled is dent corn

Question 18

why isn’t flint corn and flour corn as easy to mill

Answer 18

Flint corns are much harder and, therefore, more expensive to grind. Flour corns are easily ground but lack disease and insect resistance making them more expensive and more difficult to cultivate

Question 19

how much of the world’s corn grown is feed to livestock

Answer 19

Globally, seventy percent of corn grown is used for livestock feed

Question 20

why is it not the worst thing that most of the corn goes to livestock

Answer 20

many of the products used for livestock feed cannot be consumed by humans

Question 21

what do livestock ingredients include

Answer 21

Livestock feed ingredients include processed or unprocessed stalks and leaves, by-products of processing for human consumption and by-products of biofuel processing

Question 22

what is the largest crop produced in the usa

Answer 22

corn

Question 23

why is corn a good crop to be grown

Answer 23

Corn is a versatile, high-yielding crop and the thousands of commercial varieties make corn productive across a wide range of environments

Question 24

Is corn commonly used for direct consumption? In what form is the most common

Answer 24

Only a small fraction of the corn produced in the United States becomes food for domestic human consumption and most of that which is used for human consumption is high-fructose corn syrup

Question 25

what is involved in the corn industry

Answer 25

Corn production is widely criticized as production is geared towards biofuels and livestock feeds, it supports widespread monoculture farming and maximizing yield requires high water and fertilizer inputs

Question 26

why is something we can do to improve corn production

Answer 26

While corn is a renewable resource with a myriad of uses, its sustainability requires closer examination.