Rice, Corn, and Cereals

Flashcards covering the structure, nutritional composition, classifications, and uses of common cereal grains including wheat, rice, corn, barley, millet, oats, and quinoa.

Germ

Also known as the embryo, this is the inner portion of the kernel (approx. $2.5\%$ of the seed) where sprouting begins; it contains the highest lipid content ($6-10\%$), approximately $8\%$ of the protein, and most of the thiamin.

Endosperm

The largest part of the kernel (approx. $83\%$) which is primarily starch held in a protein matrix; it contains $70-75\%$ of the kernel's protein but is lowest in fat (less than $1.5\%$) and fiber.

Bran

The layered, outer coat of a kernel (approx. $14.5\%$ of the seed) consisting of the pericarp and seed coat; it provides cellulose and hemicellulose (fiber), $19\%$ of the protein, and minerals like iron.

Lipoxidase

An enzyme present in the grain germ that may result in rancidity.

Cereal Grain Carbohydrates

The main nutrient component making up $79-83\%$ of the dry matter, existing predominantly as starch with approximately $6\%$ fiber (cellulose and hemicellulose).

Gliadin and Glutenin

Two important proteins found in wheat, oat, rye, barley, and triticale that, when hydrated and manipulated, create a gummy, elastic gluten structure.

Alpha-amylase

A protein naturally present in cereals that promotes the dextrinization of starch into shorter-chain polymers, maltose, and glucose.

Enrichment

The process of adding back nutrients, predominantly B vitamins like Thiamin ($B_1$), Riboflavin ($B_2$), and Niacin ($B_3$), that were lost during the milling process.

Crude Fiber (CF)

A measure of fiber composed specifically of cellulose and the noncarbohydrate lignin.

Total Dietary Fiber (TDF)

A comprehensive measure of fiber including cellulose, lignin, hemicellulose, pectic substances, gums, and mucilages.

Hard Wheat

Wheat with strong protein-starch bonds and high protein content ($12-18\%$ for spring, $10-15\%$ for winter) used for bread flour due to its high gluten-forming potential.

Soft Wheat

Wheat lower in protein ($7-9\%$) and higher in starch, making it desirable for cake and pastry flours.

All-purpose Flour

A blend of hard and soft wheat containing approximately $10.5\%$ protein, designed to combine characteristics of both for various uses.

Durum Wheat

A hard, highly pigmented wheat whose endosperm is milled into semolina for use in pasta and couscous.

Parboiling (Converted Rice)

A rice enrichment method where boiling or pressure steam treatment allows water-soluble nutrients from the bran and germ to travel into the endosperm.

Long Grain Rice

Rice that is three times as long as it is wide and is high in amylose content.

Hominy

A product made from the endosperm of corn; it can be ground into grits.

Pearled Barley

Barley that has had the hull removed by the process of abrasion.

Malt

Barley processed to have sufficient enzyme content to efficiently hydrolyze starch into sugar.

Teff

A very tiny variety of millet with a diameter of approximately $1/32$ of an inch.

Rolled Oats

Oats that have had the hull removed and are then steamed and flattened (rolled).

Quinoa

A grain highest in protein, characterized by small, round, light brown kernels often used as a cooked cereal.

Pasta

A paste of milled grains, such as semolina, that is extruded through a die or put through a roller.