METHODS
SHORTCUTS
ABOUT
FAQ
SUBSCRIBE
Methods Home
All Methods
Methods eXtras
Propose a Method
Cite a Method
Technical Committees
Archived Methods
Standards Affiliations
Suppliers Guide
Check Sample Program
Harmonized Methods
AACC International Approved Methods - AACC Method 46-15.01. Crude Protein -- 5-Minute Biuret Method for Wheat and Other Grains

AACC International Approved Methods

Nitrogen

AACCI Method 46-15.01
Crude Protein -- 5-Minute Biuret Method for Wheat and Other Grains

VIEW METHOD

Objective
Compounds with peptide linkages produce a blue-violet color with copper ions in alkaline solution. This is named biuret reaction after the chemical compound biuret, first known to produce the color. The color is due to a complex bond formed between cupric ion and four peptide nitrogen atoms, two from each of two adjacent peptide chains. This method is applicable to all cereal grains, such as wheat, corn, barley, rye, and oats.