ISO 11085:2015

Overview

ISO 11085:2015 specifies laboratory procedures for the determination of crude fat and total fat in cereals, cereal‑based products and animal feeding stuffs using the Randall extraction method (a modified Soxhlet extraction). The standard covers sample preparation, two complementary procedures (Procedure A for directly extractable fats and Procedure B for total fats requiring prior hydrolysis), equipment and reagent requirements, calculation of results, and precision data. Note: ISO 11085:2015 does not apply to oilseeds and oleaginous fruits.

Key topics and technical requirements

• Two procedures
  • Procedure A - determination of directly extractable crude fat (no hydrolysis); applicable to most materials unless Procedure B is required.
  • Procedure B - determination of total fat after acid hydrolysis to release fats bound in the matrix.
• Sample preparation
  • Grind laboratory samples to <1 mm particle size; test portion typically 1–5 g.
  • For feeds, follow preparation guidance (ISO 6498 referenced).
• Hydrolysis (Procedure B)
  • Use hydrochloric acid c(HCl) = 3 mol·L⁻¹, boil for 1 hour, cool, filter and wash until acid-free.
  • For high‑fat samples (≥150 g/kg) perform a preliminary extraction before full hydrolysis.
• Extraction and gravimetric determination
  • Randall extraction system (2‑stage solvent recovery) with light petroleum (petroleum ether, 30–60 °C boiling range) as solvent.
  • Extract, evaporate solvent, dry residue (oven at 103 ± 2 °C) and weigh to determine fat mass.
• Apparatus & reagents
  • Randall solvent extraction unit, hydrolysis apparatus I or II, extraction thimbles, filtration aid (e.g., diatomaceous earth), cotton wool, acetone and analytical balance (±10 mg).
• Quality and metrology
  • The standard provides precision data: repeatability, reproducibility, critical differences and guidance on measurement uncertainty.

Applications and users

ISO 11085:2015 is used by:

• Food and feed testing laboratories performing routine fat analysis of cereals, flour, breakfast cereals, processed cereal products and compound feeds.
• Quality assurance / QC teams in cereal processing, animal feed production and ingredient supply.
• Regulatory and inspection bodies validating composition and labeling claims.
• Research groups comparing crude vs total fat contents in processed cereals and heat‑treated products.

Practical benefits include reproducible gravimetric results, clear criteria for when to apply hydrolysis (Procedure B), and guidance for accurate handling of difficult matrices (extruded, flaked, heated, or milk‑containing feeds).

Related standards

• ISO 3696 - Water for analytical laboratory use (quality of water).
• ISO 6498 - Animal feeding stuffs - Guidelines for sample preparation.
• ISO 24333 - Sampling recommendations for cereals (sampling itself is not part of ISO 11085).