Scientific Name: Glycine max

Family: Leguminosae (Legume)

Flower Colors: Purple, white

Seed Colors: Yellow, brown, black green, bicolored, variegated

Hilum Colors: Buff (colorless), black, imperfect black, brown

Pubescence Colors: Tawny (golden brown), gray

Plant Height: 20 inches to 50 inches (varies by variety and environmental conditions)

Pod Number: 0 to 400 per plant

Seed/Pod: 1 to 5; 2 to 3 more common

Hypocotyl Color: Green, purple

1 bushel = 60 pounds

1 hundredweight = 1.66 bushels

1 short ton = 33.33 bushels

1 metric ton = 2,204.6 pounds

1 metric ton = 36.7 bushels soybeans

1 short ton = 0.907 metric ton

1 hectare = 2.471 acres

1 acre = 0.405 hectares

34 bushel/acre soybeans = 2.29 metric tons/hectare

Protein content of seed » 36 ± 2%

Oil content of seed » 18 ± 2%

1 bushel = 11 pounds of oil

1 bushel = 48 pounds of protein-rich meal

Soybeans are processed by cleaning, cracking, dehulling, and rolling them into flakes. This process ruptures the oil cells for efficient extraction to separate the oil and meal components. After removal of the oil, the reaming flakes are used to produce soybean meal. The mature soybean is about 19% oil, 34% protein, 30% carbohydrate, and 17% moisture, ash, and hull (Figure 12-1). The dehulled meal contains about 48% protein. Soybeans are the only vegetable that contain complete protein.

Figure 12-1. Soybean seed composition.

United Soybean Board

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Figure 12-1. Soybean seed composition.

United Soybean Board

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Soybeans are a versatile and renewable crop that help meet food, feed, and fuel demand around the world. Soybeans are approximately 20% oil and 80% meal. Most soybeans are processed for the animal feed industry but they are also used for human food products, fuel, and industrial products (Figure 12-2).

Figure 12-2. Uses of soybeans.

United Soybean Board

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Figure 12-2. Uses of soybeans.

United Soybean Board

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The United States Grain Inspection, Packers & Stockyards Administration (GIPSA) defines soybeans as grain that consists of 50% or more of whole or broken soybeans that will not pass through an ⁸⁄₆₄ round-hole sieve and not more than 10% of other grains. Grading factors can be found in table 12-1.

Table 12-1. Grading factors and US soybean grade numbers.

Note: U.S. Sample Grade are soybeans that:

(a) Do not meet the requirements for U.S. Nos. 1, 2, 3, or 4; or
(b) Have a musty, sour, or commercially objectionable foreign odor (except garlic odor); or
(c) Are heating or otherwise of distinctly low quality.

¹ Disregard for mixed soybeans.
² In addition to the maximum count limit, stones must exceed 0.1% of the sample weight.
³ Includes any combination of animal filth, castor beans, crotalaria seeds, glass, stones, and unknown foreign substances. The weight of stones is not applicable for total other material.

Source: USDA, Grain Inspection, Packers & Stockyard Administration