Article about processed wheat

Advantages of Fresh Flour

Because grains contain only about 12% water (or about 0.6 water activity), they are not predisposed to spoilage. However, grinding removes the protective layers and endangers the grain’s biological stability. Deterioration of sensory and nutritional qualities depends on storage conditions, such as temperature, humidity, oxygen concentration, and light exposure. The lower the water activity, the lower is the loss of vitamins. For example, a vitamin E loss of only about 23% occurred after a 13 months of storage at a 0.6 water activity. In order to reduce oxidation of Essential compounds and the development of rancidity, many authors recommend storing ground flour for no more than two weeks. Antioxidants present naturally in grains (vitamin E and lecithin) help prevent oxidation of the fatty acids and the associated rancidity only for a limited time, and under ‘favorable’ conditions.

Glutamic acid decarboxylase, the most sensitive enzyme in the grain, is used to indicate the health of the grain. When heated or exposed to increased humidity, even under ‘favorable’ conditions, it losses activity very quickly in wheat. It was found to be even more sensitive in rye.

The B vitamins are liable to be destroyed by light and air, and it also seems that other substances, still unknown, are quickly destroyed. Other deteriorations include denaturation of lipoproteins, phospholipid hydrolysis, auto-oxidation of unsaturated fatty acids of phospholipids, polymerization within lipoproteins, browning, Maillard reaction of amino groups from phospholipids and aldehyde groups from sugars, and carotene and aroma losses.

Lipids in milled wheat are much more susceptible to enzymatic degradation, because enzymes are incorporated into the flour with fragments of bran and germ and with microorganisms from the surface of the grain. Associated with lipid deterioration are losses of carotenoids and vitamin E.

Much of the nutrients are removed by the mass-produced roller-ground method. Stone grinding preserves these nutrients so that the flour is healthier.

“Modern mills use serrated and flat cast iron rollers to separate the bran and germ from the endosperm. The endosperm is ground to create white flour which may be recombined with the bran and germ to create whole wheat or graham flour.”