Overview
EN ISO 16472:2006 - "Animal feeding stuffs - Determination of amylase-treated neutral detergent fibre content (aNDF)" - is a CEN-adopted ISO standard that specifies laboratory methods to measure the amylase-treated neutral detergent fibre (aNDF) in all types of animal feed. The standard provides both a gravimetric routine method and a reference method, describing sample preparation, reagents, apparatus, procedure, calculation, and quality assurance for reporting aNDF as a mass fraction (percent).
Key topics and technical requirements
- Principle: Use of a neutral detergent (ND) solution combined with a heat-stable alpha‑amylase to dissolve proteins, lipids, sugars and starches, leaving an insoluble fibrous residue (cellulose, hemicellulose, lignin).
- Reagents: Specifications for ND solution (pH adjusted to 6.95–7.05), sodium sulfite, heat‑stable alpha‑amylase (standardized to remove starch), iodine solution, and example substrate (dried hominy corn).
- Apparatus: Requirements include analytical balance (0.1 mg readability), cyclone/cutter mills for grinding (target particle size ~220–260 µm), Gooch fritted‑disc crucibles or P2 crucibles, vacuum filter manifolds (e.g., Fibertec-type), and a continuous boiling water supply for rinsing.
- Procedure variants: Traditional reflux/gravity procedure and adaptations for Fibertec-type automated apparatus; instructions for handling different sample types and avoiding artefact fibre (drying