What is the standard for crude fiber content in grain?

What is the standard for crude fiber content in grain?‌

Crude Fiber Classification Standards‌

Based on relevant standards, the crude fiber content in grains can be categorized into three levels:

‌Low level‌: Dietary fiber content <3g per 100g solid food

‌Medium level‌: Dietary fiber content ≥3g and <6g per 100g solid food

‌High level‌: Dietary fiber content ≥6g per 100g solid food

‌Crude Fiber Content in Major Grains‌

‌Cereals‌:

Whole wheat flour: Fiber content ≥9g/100g (meets coarse grain standards)

Refined flour: Fiber content ≤3g/100g (classified as fine grain)

Wheat grains: 4-10% crude fiber content

Corn: 4-10% crude fiber content

Buckwheat noodles: 4-10% crude fiber content

Job's tears noodles: 4-10% crude fiber content

Barley: ≥6g/100g (high level)

‌Tubers‌:

Potatoes, sweet potatoes, etc.: ~3% crude fiber content

‌Legumes‌:

Soybeans, green beans, broad beans, etc.: 6-15% crude fiber content

Black soybeans: 6-15% crude fiber content

Soybeans: ≥6g/100g (high level)

‌Testing Standards and Methods‌

Crude fiber determination is primarily based on the following national/international standards:

GB/T 5515 Inspection of Grains and Oils: Determination of Crude Fiber

GB/T 6434-2006 Determination of Crude Fiber in Feed

ISO 6865:2000 Animal Feeding Stuffs: Determination of Crude Fiber

‌Precautions‌

Crude fiber content is significantly affected by processing methods; whole grains retain more fiber.

During testing, control sample particle size (18-mesh sieve) and fat content (cold extraction required if exceeding 1%).

Crude fiber measurement results include cellulose, hemicellulose, lignin, and other components.

ST116 Coarse Fiber tester tests raw fiber content according to acid and alkali boiling method.It adopts accurate concentration acid and alkali to boil samples in particular condition, then remove soluble substances by ether, deduct the amount of minerals by high temperature burning.