Brown rice is the rice grain to remove the outer protective skin layer of the husk after the caryopsis, the inner protective skin layer (pericarp, seed coat, bead layer) intact rice seeds, due to the inner protective skin layer of crude fiber, chaff wax, etc. more taste coarse, dense texture, cooking is also more time-consuming, but it is a remarkable slimming effect. Compared with ordinary delicate white rice, brown rice vitamins, minerals and dietary fiber content is richer, is regarded as a green health food.
Characteristics
Brown rice is a glabrous fruit with a smooth and shiny surface. In brown rice grains, the side of the rice grain with embryo is called belly white, and the side without embryo is called the back. Brown rice grain surface *** have five longitudinal grooves, the back of a dorsal groove, the two sides of high-quality rice brown rice
each has two grooves called rice. Brown rice grooves at the cortex in the rice milling is difficult to remove all, for the same variety of rice, grooves at the more skin, can be considered the lower the precision of processing, so the precision of rice processing is often used to the grain surface and the back of the grooves of the degree of retention of the skin to indicate. The depth of the longitudinal groove varies with different varieties of rice, and it has a certain impact on the rice yield. Some brown rice in the abdomen or the center part of the grain shows opaque white spots, which is the abdomen white or heart white. Abdominal white and heart white are caused by unsuitable climate, rainfall and fertilizer during the growth of rice.
The pericarp of brown rice consists of the exocarp, mesocarp, transverse cells and tubular cells, with a total thickness of about 10 microns. Seed coat is extremely thin, thickness of about 2 microns, structure is not obvious, some brown rice seed coat contains pigment and color. The endosperm is a thin film-like tissue adhering to the seed coat, with a thickness of l-2 microns, and it is difficult to distinguish it from the seed coat. The endosperm is the largest part of the rice grain and consists of a layer of starch and amyloplasts. The amyloplast cells are filled with tiny pasty grains containing proteins, fats, etc., but not starch. The starch cells are filled with starch grains. Embryo is located at the base of the ventral surface of the rice grain, oval, composed of germ, embryonic stem, radicle and shield, shield and endosperm connected to the endosperm, seed germination secretion of enzymes, decomposition of endosperm in the supply of nutrients to the embryo.