Pro Tip: Certain flour components can tell a baker a lot about the quality of their flour, which will have a major impact on finished product.
Why understand flour quality? Why run quality tests on bulk flour?
It’s because flour is more than 50% of your formulation. A little change in flour components will have a significant effect on your mixing requirements and bread quality. By understanding moisture, ash and protein; particle size; water absorption; dough machinability, and enzyme activity, bakers can optimize flour performance.
Moisture, ash and protein
A quick method for your bakery plant is to implement a near infrared instrument for your bulk flour receiving procedure. This allows you to run a quick analysis of moisture, ash and protein on your incoming flour, which should not be higher than 14% in moisture.
Otherwise, there will be concerns for pest and microbial growth in the flour. Most bulk flours are also purchased based on 14% moisture. Therefore, receiving more than 1% extra water in a truckload would not only mean that the baker is paying for more water in the flour but also that the baker would also have to readjust water absorption levels at the mixer.
Particle size test
This test, administered typically by a Ro-Tap, indicates the granularity of the flour. The smaller the particle size, the larger the surface area of the flour particles. Surface area affects chemical property changes and water absorption. At least 98% of bread flour should pass through a US standard mesh number 70. Flour’s particle size correlates with quality indicators of the flour. It helps assess the following:
1. Flour’s purity (whether it has higher bran and minerals).
2. Rate and extent of water absorption of wheat flours during mixing.
3. Mechanical damage of starch during milling.
The particle size index, or PSI, is an indicator of wheat milling performance. The PSI for hard wheat for baking bread is around 13% to16%.
Water absorption
Water absorption analysis has traditionally been performed by the farinograph at the mills. All three instruments – the farinograph, mixolab and mixograph – provide this analysis, which results in a prediction of the water absorption, dough development times, dough strength and the stability of the dough. In addition, the mixolab has heat treatment after the full mixing step to show a graph of how the dough cooks. This would help predict oven spring and softness of the bread over shelf life.
Dough machinability
In addition to the farinograph and mixolab readouts, high output doughs must also have the ability to work with the following existing dough conditioners:
• Tenacity
• Elasticity
• Extensibility
• Baking strength
All these properties can be read on an alveograph. It is a rheological tool used to assess the baking performance of flours and dough conditioners. It is based on injecting air into a thinly stretched sheet of dough to form a bubble, simulating gas release and retention during dough fermentation.
Enzyme activity
The falling number of a flour is related to the amount and activity of the cereal enzyme alpha amylase, which is present in the wheat after harvesting. Wheat kernels with high moisture levels usually exhibit high levels of alpha amylase. Falling number should not be lower than 250.
Now that you know what to look for in flour quality, we’ll learn how to control it, or work with it in my next Pro Tip.
Lin Carson, PhD, is the founder and chief executive officer of Bakerpedia. You can connect with her on LinkedIn.
