Vol. XXI · Grains, Rice and Noodles Plate 1 of 10grain, bran, germ, endosperm, whole grain, refined, white flour, wholemeal, brown rice, white rice, fibre, rancidity, milling, extraction rateMT

The Grain.

Brown rice and white rice are the same seed. White rice is what is left when the outside and the embryo have been polished away.

Wheat, rice, maize, barley, oats, rye, millet and sorghum all share one plan. Outside is the bran: layers of fibre-rich coat holding minerals, B vitamins and the protein-rich aleurone layer. At one end is the germ, the embryo, rich in oil and vitamin E. The rest, most of the seed, is the endosperm: starch granules packed in a matrix of protein — the protein that, in wheat, becomes gluten (VI.10).

Milling and polishing remove the bran and germ to give white flour and white rice. What is gained is keeping quality — the germ's oil goes rancid within months (IX.4), so whole-grain flour keeps far less long than white — plus fast, even cooking and a softer texture, because water no longer has to get through the bran (XXI.8). What is lost is most of the fibre, much of the fat, minerals and vitamins, which is why white flour is often fortified. The workshop compares whole with refined.

Below: fibre, protein and fat per 100 g of the whole and the refined form of the grain you choose (USDA FoodData Central), and how many times more fibre the whole form keeps.

What you will learn
Workshop
Composition per 100 g raw from USDA FoodData Central, SR Legacy: whole-grain and white all-purpose wheat flour; brown and white long-grain rice.

What the miller takes away

Whole-grain wheat flour has about 4 times the fibre of white flour and about 2.5 g of fat per 100 g against 1.0 g; brown rice has about 2.8 times the fibre of white. The fat is the reason whole-grain flour should be bought in small amounts, kept airtight and cool — in the freezer if it will not be used within a couple of months — and smelled before use: rancid flour smells of paint or cardboard.

In cooking, whole grains need more water and more time, and they are heavier: whole-wheat bread rises less because bran cuts gluten strands (XXIV.1), so many bakers mix it with white flour or give the dough a long rest. Brown rice needs about twice the cooking time of white (XXI.3). The flavour is nuttier and deeper. In Chinese and Japanese kitchens white rice has long been preferred for its texture, and 糙米 (brown rice) is eaten mostly for health; parboiled rice, steamed in its husk before milling, drives some of the bran's vitamins into the grain.

At the stove

Cook white and brown rice side by side, each by the absorption method with the right water, and time them. Taste both plain.

Beriberi, a disease of thiamine (vitamin B1) deficiency, spread through Asia with steam-powered rice polishing in the nineteenth century; the Dutch physician Christiaan Eijkman showed in the 1890s that chickens fed polished rice developed it and those fed brown rice did not — work that led to the discovery of vitamins.

Terms

Bran
The fibrous outer layers of a grain.
Germ
The oily embryo of a grain.
Endosperm
The starchy store that makes most of a grain.
Whole grain
Grain with bran, germ and endosperm all kept.
A grain is bran, germ and endosperm. Refining removes bran and germ: keeps longer and cooks faster, but loses fibre, fat and vitamins. Store whole grains cool and airtight.

Sources

  1. USDA FoodData Central, SR Legacy (April 2018), public domain.
  2. H. McGee, On Food and Cooking: The Science and Lore of the Kitchen, 2nd ed., Scribner, 2004.
  3. Typical storage guidance for oils, nuts and wholemeal flour at room temperature, sealed and dark: refined oils about a year, olive oil 18 months to two years, walnut and other polyunsaturated oils a few months, shelled nuts and wholemeal flour a few months; cold storage extends it several-fold (USDA FoodKeeper). The course scales these with an Arrhenius activation energy of 80 kJ/mol, a teaching value.