ISO 2448:1998

Overview

ISO 2448:1998 is an internationally recognized standard developed by the International Organization for Standardization (ISO) that specifies the method for determining ethanol content in fruit and vegetable products. This method is crucial for quality control and safety assessments in the food industry, ensuring that ethanol levels remain within acceptable limits. The standard is applicable to products with ethanol content up to 5% (m/m) and provides guidelines for both solid and liquid fruit and vegetable products, including handling products with essential oils.

Key Topics

• Scope and Applicability
  ISO 2448:1998 covers the chemical analysis of ethanol in fruit and vegetable-derived products, such as juices, purees, jams, and marmalades. It excludes products with ethanol content exceeding 5% by mass.

• Definition of Ethanol Content
  Ethanol content is determined by mass percentage in solid products and grams per 100 ml in liquid products.

• Method Principle
  The method involves steam distillation to separate ethanol from the product, followed by oxidation using potassium dichromate in sulfuric acid. The excess dichromate is then quantified by a redox titration with ammonium iron(II) sulfate, using iron(II)-1,10-phenanthroline as an indicator.

• Reagents and Apparatus
  The standard specifies the use of analytical grade reagents including sulfuric acid, potassium dichromate, ammonium iron(II) sulfate, and potassium permanganate. Required laboratory apparatus include distillation units, volumetric flasks, burettes, pipettes, and balances capable of precise measurements.

• Sample Preparation
  Solid and thick products must be homogenized gently to avoid heating, while liquid products require thorough mixing. Samples should be representative and handled to prevent any alteration prior to testing.

• Testing Procedure
  The process includes:

  • Distillation of the test sample under alkaline conditions to collect ethanol in a volumetric flask
  • Oxidation of ethanol in the distillate with potassium dichromate solution in sulfuric acid medium
  • Back titration of unreacted dichromate with ammonium iron(II) sulfate until a color change indicates the endpoint

• Special Considerations
  For products containing essential oils, a modified procedure outlined in Annex A ensures the removal of oils before titration to avoid turbidity and inaccurate results.

• Result Expression and Repeatability
  The ethanol content is calculated with precise formulas for both solids and liquids. The method guarantees repeatability with results differing by no more than 1% on average for the same sample tested independently.

Applications

ISO 2448:1998 is widely applied in the agricultural and food processing industries for the following purposes:

• Quality Control in Fruit and Vegetable Processing
  Ensures consistent ethanol levels in products like juices, purees, jams, and syrups, optimizing taste, safety, and regulatory compliance.

• Regulatory Compliance
  Assists manufacturers in meeting national and international food safety standards related to ethanol content in fruit and vegetable products.

• Research and Development
  Supports development of new products by providing reliable chemical analysis for ethanol, critical in fermentation and preservation processes.

• Export and Import Verification
  Used by customs and quality assurance bodies to verify ethanol content, facilitating international trade of processed fruit and vegetable products.

Related Standards

• ISO/TC 34 – Agricultural Food Products
  The technical committee responsible for fruit and vegetable product standards complements ISO 2448 with various related analytical methods.

• ISO 659 – Fruit and Vegetable Juices - Determination of Ethanol Content
  A method for ethanol measurement specifically tailored for juices, which may be used alongside ISO 2448 depending on product type.

• International Electrotechnical Commission (IEC) Collaboration
  ISO collaborates with IEC for electrotechnical aspects, pertinent to equipment calibration and electronic measuring devices used in ethanol determination.

Keywords: ISO 2448, ethanol content, fruit and vegetable products, chemical analysis, ethanol determination, potassium dichromate titration, food quality control, ethanol measurement in food, fruit juice testing, ethanol in jams and purees, agricultural product standards.