ISO 16634-2-2016 PDF

Full title and description

Food products — Determination of the total nitrogen content by combustion according to the Dumas principle and calculation of the crude protein content — Part 2: Cereals, pulses and milled cereal products (ISO 16634-2:2016). This International Standard specifies a Dumas combustion method for measuring total nitrogen and for calculating crude protein in cereals, pulses and milled cereal products; it is intended for routine and regulatory laboratory use where rapid, accurate nitrogen/protein determination is required.

Abstract

ISO 16634-2:2016 defines a procedure based on combustion (Dumas principle) to determine total nitrogen and to calculate crude protein in cereal grains, legume pulses and milled cereal products. The method does not distinguish protein nitrogen from non‑protein nitrogen and uses conversion factors to convert measured nitrogen to crude protein. It is presented as an alternative to, and comparable with, Kjeldahl-based determinations for the specified matrices.

General information

• Status: Published (International Standard).
• Publication date: 2016-05 (Edition 1, 2016).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 67.050, 67.060 (general methods of tests and analysis for food products; cereals, pulses and derived products).
• Edition / version: Edition 1 (2016).
• Number of pages: 24 (official ISO edition page count).

Key bibliographic and status metadata above are taken from the ISO bibliographic record and national-adoption listings for the standard.

Scope

This part of ISO 16634 specifies a method for the determination of total nitrogen content by combustion (Dumas principle) and the calculation of crude protein content specifically for cereals, pulses and milled cereal products. It is applicable to the matrices named but, like Kjeldahl, does not separate protein nitrogen from non‑protein nitrogen; conversion factors appropriate to the commodity are used when calculating crude protein. The standard provides requirements for sample preparation, analysis, instrument calibration, calculation and reporting for these sample types.

Key topics and requirements

• Principle: determination of total nitrogen by combustion (Dumas method) with measurement of resultant gases and calculation of nitrogen content.
• Sample preparation: guidance for representative sampling, grinding/milling and sub‑sampling of cereals, pulses and milled products.
• Calibration, instrument performance and quality control: use of appropriate standards, calibration routines and blank/sample controls to ensure accuracy and repeatability.
• Calculation of crude protein: application of specified nitrogen‑to‑protein conversion factors and clear reporting of the factor used.
• Comparability and limitations: notes on comparability with Kjeldahl results and statement that the method does not distinguish protein vs non‑protein nitrogen.
• Reporting: recommended result formats, significant figures, and statements on method/conditions used.

The items above summarize the main technical and procedural requirements contained in the published standard.

Typical use and users

Primary users are food and grain testing laboratories, cereal processors and millers, quality control and R&D teams in the cereal and pulse supply chain, regulatory laboratories and standards bodies. Typical uses include routine quality control, specification verification, nutritional labelling calculations, trade testing and method validation/comparison with Kjeldahl or other nitrogen determination methods.

Related standards

ISO 16634 is a multipart family addressing Dumas combustion nitrogen determination for different food/feed matrices. Related documents include ISO 16634-1 (Part 1 — oilseeds and animal feeding stuffs, originally published 2008 and subject to later revision activity) and earlier technical specifications that preceded the 2016 publication. Where relevant, laboratories also refer to Kjeldahl-based standards and matrix-specific methods (for example ISO/IDF standards for dairy) when choosing an analytical approach.

Keywords

Dumas method; combustion analysis; total nitrogen; crude protein; cereals; pulses; milled cereal products; food analysis; method validation; calibration; sample preparation; nitrogen‑to‑protein conversion.

FAQ

Q: What is this standard?

A: ISO 16634-2:2016 is an International Standard that specifies a Dumas combustion procedure to determine total nitrogen and calculate crude protein specifically for cereals, pulses and milled cereal products.

Q: What does it cover?

A: It covers the analytical principle (combustion/Dumas), requirements for sampling and sample preparation for the named matrices, instrument calibration and quality control, calculation of crude protein using conversion factors, and reporting of results. The method does not distinguish protein nitrogen from non‑protein nitrogen.

Q: Who typically uses it?

A: Accredited and routine food testing laboratories, cereal processors and millers, feed and food quality teams, regulatory and standards bodies, and research groups comparing nitrogen determination methods.

Q: Is it current or superseded?

A: As published in May 2016 it is the current Part 2 edition; ISO records indicate life‑cycle review activity and the standard is subject to periodic review (standards are normally reviewed every five years). Users should check their national standards body or ISO catalogue for any amendments or revisions since 2016.

Q: Is it part of a series?

A: Yes — ISO 16634 is a multipart series addressing Dumas combustion nitrogen determination for different food/feed matrices (for example Part 1 covers oilseeds and animal feeding stuffs). The series aligns methods across commodity types while noting matrix‑specific requirements and conversion factors.

Q: What are the key keywords?

A: Dumas method, total nitrogen, crude protein, cereals, pulses, milled products, combustion analysis, sample preparation, calibration, nitrogen‑to‑protein conversion.