Overview
ISO 17718:2013 - "Wholemeal and flour from wheat (Triticum aestivum L.) - Determination of rheological behaviour as a function of mixing and temperature increase" - defines a laboratory method to characterise the rheological behaviour of wheat wholemeal and flour under combined kneading and controlled temperature increase. The method records dough torque during mixing while heating, providing data on water absorption, dough development, gluten strength, starch gelatinization and retrogradation, and enzyme effects. The standard is applicable to industrial or laboratory‑milled samples of common wheat (Triticum aestivum L.).
Key technical topics and requirements
- Principle: Measure torque between mixing arms during kneading with in‑bowl temperature profile (start at 30 °C, heat to 90 °C, hold, then cool), giving a rheological curve that reflects protein and starch behaviour.
- Critical parameters recorded: C1 (target maximum consistency), C2 (post‑C1 minimum), C3 (post‑gelatinization peak), C4 (drop after C3), C5 (final consistency), stability time, time T1, and estimated temperatures D1–D5.
- Water absorption determination: A preliminary test adjusts water addition to reach the target consistency (C1 ≈ 1.10 ± 0.05 Nm).
- Equipment: A Mixolab‑type instrument (e.g., Chopin Mixolab) or equivalent is specified to deliver 80 r/min mixing and programmable temperature profile; laboratory mill and balance are required for sample preparation and weighing.
- Supporting standards: Moisture determination per ISO 712; recommended sampling guidance referenced (ISO 24333) and laboratory milling methods noted (e.g., ISO 27971).
- Procedure elements: Sample milling (if needed), moisture measurement, device preparation, two‑step testing (water absorption then full rheological test), parameter recording and result expression to defined precisions.
- Quality/precision: The standard contains precision and interlaboratory test information (repeatability, reproducibility, uncertainty) and requires reporting of test conditions and results.
Practical applications and typical users
- Flour and milling quality control: Determine functional performance of wholemeal and white flours for industrial and craft milling.
- Baking and product development: Inform formulation, process adjustments and predict dough behavior during mixing and baking.
- Breeding and grain evaluation: Compare genotypes for protein and starch functional properties.
- Research & R&D: Study interactions of gluten and starch under thermo‑mechanical stress.
- Regulatory and trading labs: Provide standardized rheological data for specification and acceptance testing.
Typical users: cereal chemists, mill QC laboratories, bakeries’ technical teams, food scientists, plant breeders, and instrument manufacturers.
Related standards (for context)
- ISO 712 - moisture determination of cereals and cereal products
- ISO 24333 - sampling of cereal grains (recommended)
- ISO 27971 - laboratory milling guidance (referenced)
Keywords: ISO 17718:2013, wholemeal, wheat flour, rheological behaviour, Mixolab, water absorption, dough stability, starch gelatinization, gluten strength, flour testing.