Flour may seem like a simple ingredient to the average person. However, those in the milling and baking industries know that flour is a dynamic product with several measurable properties that influence how it adapts to produce a baked product.

Determining what makes good flour or dough is a puzzle. Each piece of the puzzle corresponds to the information provided by multiple testing methods. The invention of the Alveograph test over 100 years ago was the spark for more research into the complexities that determine flour and dough quality. Several new technologies emerged over this period. Still, each invention typically falls into one of three flour and dough quality analysis categories:

  1. Compositional Analysis: Quantitative analysis of what parameters are in the flour
  2. Rheological Analysis: The understanding of how the different components in the flour behave together
  3. Functional Analysis: Determining why the dough behaves as it does

There is currently no one-solution-suits-all when determining flour quality. All three of these analysis categories complement one another to determine how flour will behave as a dough, and how that dough will produce a product.

#1: The Role of Compositional Analysis in Flour & Dough Quality

Compositional analysis is the process of quantifying the finite properties of flour. Flour protein, moisture, and ash content are the most common parameters for compositional analysis. Many millers and bakers use near-infrared (NIR) technologies to measure these figures. This article explains the NIR analysis process and additional advantages over other technologies.

The SpectraStar XT-F, shown here, includes calibrations to measure finished flour moisture, protein, ash, as well as water absorption and rheological parameters.

From a miller's perspective, ash content is a crucial indicator of milling yield. Suppose millers can get closer to the maximum ash value required by the baker's specifications. In that case, they will increase their milling yield and, thus, increase the amount of flour for sale. Accurate measurements are essential to meet this goal. One method to measure ash is with an ash furnace (reference method NF ISO 2171). However, while highly accurate, ash furnaces can take several hours to output results.

NIR technologies are a secondary measurement method that applies calibrations obtained from primary methods – like an ash furnace – to measure flour quality parameters quickly. For instance, the SpectraStar™ XT-F Flour Analyzer measures moisture, protein, and ash content of a flour sample in under 30 seconds, with an average error of only 0.017% compared to an ash furnace measurement. This means millers can make ash measurements a routine process optimization test. At the same time, bakers can also use NIR to verify the compositional properties promised by their miller.

Additionally, an imbalance in damaged starch – another important compositional parameter and a natural byproduct of the milling process – can lead to significant production issues like sticky dough, poor final product volume, and other unwanted visual defects. This is because damaged starch multiplies water absorption capacity and leads to higher or lower sugar production.

Adding water or flour to a dough to obtain the ideal consistency for home bakers can be done more easily than in a high-volume baking operation. Depending on the finished product, millers and bakers should aim to achieve a specific balance between damaged starch and protein used in the flour. This infographic explains more about the importance of damaged starch analysis.

One simple and automated method to measure starch damage is with the SDmatic. The SDmatic is a fully-automated, enzyme-free damaged starch analyzer based on the recognized amperometric method (Medcalf & Giles). SDmatic accurately measures iodine absorption in a diluted flour suspension. The more iodine is absorbed by the starch, the more damaged starch is in the flour sample. The SDmatic test is recognized in several international standards (NF EN ISO 17715:2015, ICC 172, AACC 76-33.01, FTWG N°24).

Now with an understanding of what parameters are in your flour, next is to analyze how these components will behave as a dough.

#2: The Role of Rheological Analysis in Flour& Dough Quality

Rheological analyzers measure dough properties at the early stages of baking, particularly the physical properties of flour when mixed with water. These properties provide processing and final product quality indicators, including extensibility, baking strength, and behavior during mixing, heating, and proofing.

As mentioned earlier, the most globally-recognized rheological analysis method is the Alveograph test, which analyzes the viscoelastic properties of gluten in the dough. During the bread-making process, gas develops and exerts pressure on dough in a multilinear process. The Alveograph test measures how much pressure over time is necessary to burst an air bubble in the dough. Therefore, the Alveograph test measures the characteristics of dough in a multilinear manner rather than a linear one.

The Alveograph test - demonstrated here by the Alveolab -,submits an air bubble to a dough sample to measure how much pressure isnecessary to burst the dough over time.

Along with gluten quality, protein and starch analysis also have a significant role in the rheological analysis of flour and dough. Protein and starch affect a dough's development and final product quality.

The only true way to understand how protein and starch affect the final product is to put the flour through the production process. However, technologies exist to help bakers and millers characterize flour quality and obtain baseline expectations using a small sample.

For instance, the Mixolab 2 Universal Dough Characterizer enables users to evaluate dough behavior. Mixolab 2 is the only instrument that simulates the constraints a dough undergoes from the mixing process through baking and provides expectations for product shelf life. It allows bakers and millers to check the quality of their flours, assess enzyme impact, refine new formulations (including fiber-rich and gluten-free varieties), and improve their production efficiencies. 

After mixing and before baking, there is one more critical step in the process: proofing. The fermentation/proofing process of a dough plays a massive part in keeping final products consistent while also crucial when selecting yeast strains for new recipes. Using the Rheo F4, a rheological analyzer to monitor dough behavior during proofing, bakers can measure all types of yeast for dough development, gas production from yeast action, dough porosity, and more.

Now that you can predict how flour will behave as dough, your next step is to determine why those properties function as they do.

#3: The Role of Functional Analysis in Flour & Dough Quality

Even if the flour has similar compositions and rheological properties from one batch to the next, it can exhibit different performances on a process line. Therefore, functional analysis is the final phase of a comprehensive flour & dough quality control program.

Glutenins, damaged starch, and pentosans are vital functional components that affect dough behavior during production and baking:

  • Glutenins affect the extensibility and elasticity of the dough
  • Damaged starch, as mentioned above, affects dough stickiness
  • Pentosans affect dough viscosity

In the 1990s, the Solvent Retention Capacity (SRC) Method was developed to test the quality of cookie and cracker flours. The SRC Method measures hydration based on the increased swelling capacity of a flour's different polymers when brought into contact with certain solvents.

While rheological instruments measure the combined effects of the three functional components, the SRC Method complements these tools to analyze each polymer's specific contribution to the final behavior of the dough. With this information, the baker can anticipate the water absorption potential of flour. 

The SRC method is based on enhanced swelling behavior of principal flour polymer networks in the selected single diagnostic solvents shown here.

The manual SRC Method (AACC 56-11.02) is a labor-intensive process requiring several successive steps. Because of these manual steps, the repeatability of the manual SRC method is challenging.

However, with SRC-CHOPIN 2, the industry’s only internationally standardized SRC instrument (AACC 56-15.02, ICC 186), bakers and millers have access to an automated method to obtain a vital functional analysis of flours with repeatable results. 

Completing the Flour & Dough Quality Puzzle Requires a Comprehensive Approach

What is in the flour? How do the components behave together? Why the dough behaves as it does?
Type of Analysis Compositional Analysis Rheological Analysis Functional Analysis
Technology/Solution SpectraStar XT-F SDmatic Alveograph Test Series Mixolab 2 Rheo F4 SRC-CHOPIN 2
Measurement Protein, moisture, ash Damaged starch Dough properties (gluten) Dough properties (protein & starch) Dough proofing Glutenins, damaged starch, pentosans

Quality control is not just about meeting specifications and numbers. The goal is to obtain actionable information to make data-driven decisions to meet consumer needs and protect a brand. Flour and dough are complex products, so finding the right balance of compositional, rheological, and functional properties will help you deliver consistent, top-quality products to consumers. Additionally, these efforts will help your company save on ingredient costs, reduce waste, and build a positive reputation for your brand. 

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