A corn flour milling machine could use rollers, hammers or stones to grind the grain. One of the chief aims is to keep the temperature down.
Traditionally of course stone grinders were driven by very slow water-wheels and windmills; little heat was generated. Or the grain was ground by hand.
These days most industrial grinding of maize is done using a roller or hammer-mill.
This old roller mill is used mainly for chicken feed but also for the first phase before the maize goes into a small stone grinder.
The aim is to produce "straight-run;" wholemeal where there is no separation of the bran, germ and endosperm. The full complement, in exactly the same ratio as in the grain, of fibre, protein and starch is found in the flour; the vitamins, minerals and phytonutrients too.
The grooved steel rollers flake off the bran and germ while the starch is cracked into coarse pieces.
Normally this corn flour milling machine would be powered by a 3-phase electric motor but a single will do provided all the grain is completely ground so that none remains between the rollers, as above, at the end of the operation.
Thereafter the half-ground corn goes to this little stone mill which produces fine 100% wholemeal containing all the bran and germ; and the full complement of vitamins, minerals and antioxidants.
The oil in corn flour is the reason that millers refine the grain; that and there is a greater profit margin selling the best part, the "harminy chop" to the pig farmers.
So the millers remove the oils which begin to go rancid once the grain is cracked. Freshly-ground wholemeal should be consumed within a week; longer if refrigerated or frozen.
Stone mills driven by electric motors generate a lot of heat; it's a good idea to freeze the grain before grinding.
"Most of nutrient’s concentration is higher in outer part of the grain, so differential milling or refining results in reduced nutrient content except starch."
Hominy chop contains most of the protein and fat, located in the maize germ. Millers imply that it's what is left after the best part, the starch, has been taken out for human consumption.
This is a contentious point; some would claim that the germ and bran are in fact the best parts. Without them the cornmeal is highly glycemic and fattening.
The bran contains the fibre which is known to stimulate the growth of beneficial bacteria, the microbiome, in the colon. However it is considered a byproduct and most of it goes to animal feed.
Scientists have also shown that the oil in corn bran lowers the total blood cholesterol levels by a massive 29%.
Phenols in corn bran also have anti-diabetic properties and give protection to the skin against the noxious effect of excessive exposure to sunlight.
The germ in corn is double that in other grains, about 5% but may be removed by modern corn flour milling machines, if the three fractions are split as is customary. The oil makes up about half of it.
These are poly and mono-unsaturated fats; there is no cholesterol.
"The majority of the tocols are found in the oil-rich germ layer; and as the germ layer in corn is larger, its concentration is also higher. Degerming and milling remove between 90 and 95% of the vitamin E content."
The details are not important as it is complex biochemistry, but the bran contains phenols and ferulic acid which are potent antioxidants; they are released in the colon which is constantly under attack because of all the fecal material making it prone to aggressive malignant-tumours.
This ferulic acid found in the bran also exhibits antimicrobial activity against pathogens in the colon.
All these benefits are lost when a corn flour milling machine is used that separates the bran from the rest of the kernel; it is usually discarded and finds its way into animal feed.
"In the process of refining grain, the bran is separated, resulting in the loss of dietary ﬁber, vitamins, minerals, lignans, phytoestrogens, phenolic compounds, and phytic acid."
- Oghbaei and Prakash 
The bran of grains also contains lignins which have a potent anti-tumour effect against malignant neoplasms in the breast. They too are lost in the refining of corn.
Phytosterols found in the bran have a structure similar to animal cholesterol; they compete with LDLs for absorption in the small intestine making us less prone to the toxic lipoproteins in the blood requiring medication like statins.
One of these phytonutrients in the bran is gamma-tocopherol, an isomers of vitamin E that gives protection against malignant prostate tumours.
They too are lost if the corn flour milling machine refines out the bran making us prone to raised cholesterol, statin-prescription and neoplasms in the nether parts.
Milling and subsequent refining by removal of the bran and germ results in substantial loss of the vitamin content.
The take home in all of this is that the bran and germ of corn have many important biological functions in the body. They should certainly not be considered byproducts and used primarily as animal feed. We humans also desperately need mealiemeal, as it is known in South Africa, that is unrefined.
We look forward to corn flour milling machines in every village and town that produce "straight run" mealiemeal for the general populace. Lower rates of diabetes are anticipated; and less malignant tumours of the breast, prostate and colon.
"Recent studies show the beneficial effect of phytic acid, the content of which is high in cereal bran. It is effective in prevention of coronary disease and has anticarcinogenic properties."
A corn flour milling machine is about the only way to obtain freshly-ground porridge for home use; the small Mio above will do the job but it is recommended to pass the grain through twice, the first to grind the grain coarsely followed by a finer setting.
When browsing use right click and "Open Link in New Tab" or you may get a bad gateway signal.
Our newsletter is entitled "create a cyan zone" at your home, preserving both yourself, the family and friends, and Mother Earth for future generations. We promise not to spam you with daily emails promoting various products. You may get an occasional nudge to buy one of my books!
Here are the back issues.
Did you find this page interesting? How about forwarding it to a friend, or book and food junkie; or, better still, a Facebook or Twitter tick would help.
56 Groenekloof Rd,