ISO 8262-2:2005

Overview

ISO 8262-2:2005 (IDF 124-2:2005) specifies the reference method for determination of fat content in edible ices and ice-mixes using the Weibull–Berntrop gravimetric method. This part of the ISO 8262 series is intended for products where the Röse–Gottlieb (RG) procedure is unsuitable-typically formulations with high levels of stabilizers, thickeners, egg yolk, fruit or combinations of these. The method produces a mass-fraction (%) result for total fat by acid digestion, filtration and solvent extraction.

Key topics and technical requirements

• Principle: Boil a test portion with dilute hydrochloric acid (≈20% HCl), filter the hot digest to retain fatty residue, dry the filter, extract fat with n-hexane or light petroleum, evaporate solvent and weigh the extract (Weibull–Berntrop principle).
• Reagents: Dilute HCl (~20% w/w, density ≈1.10 g/ml); extraction solvent n‑hexane or light petroleum (boiling range 30–60 °C).
• Quality checks:
  • Extraction solvent residue after distillation: ≤ 1.0 mg (blank test).
  • Filter paper residue in blank test: ≤ 2.5 mg.
• Apparatus highlights: Soxhlet or equivalent extraction apparatus (150 ml flask, 40–60 ml siphon volume), pleated 150 mm filter papers, extraction thimbles, analytical balance, drying oven (102 °C ± 2 °C), distillation setup and controlled water baths.
• Sampling & storage: Laboratory samples of liquid/viscous products kept at 2–4 °C; frozen ice samples maintained at ≤ −18 °C. (ISO 707 recommended for sampling procedures.)
• Precision: The standard includes sections on interlaboratory tests, repeatability and reproducibility to support method validation and quality control.

Applications

• Routine quality control and batch verification in ice-cream and frozen dessert manufacturing.
• Regulatory compliance and product labelling verification for declared fat content.
• Ingredient and formulation testing where high stabilizer, fruit or egg contents render RG or SBR methods unreliable.
• Contract testing and dispute resolution where a reference gravimetric method is required.

Who should use this standard

• Dairy and food-testing laboratories performing fat analysis of frozen desserts.
• Quality assurance teams at ice-cream manufacturers and co-packers.
• Regulatory agencies and certification bodies assessing nutritional declarations.
• R&D scientists developing or reformulating ice-mix products.

Related standards

• ISO 8262-1 / IDF 124-1 - Part 1 (infant foods) and ISO 8262-3 - Part 3 (special cases).
• ISO 7328 - Röse–Gottlieb method (other milk products).
• ISO 707 - Recommended sampling methods for milk and milk products.

Keywords: ISO 8262-2:2005, Weibull‑Berntrop gravimetric method, fat content determination, edible ices, ice‑mixes, reference method, milk products, IDF 124-2.