Cigi study shows wheat flour stored over time improves baking performance

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Flour stored under ambient conditions over a specific length of time can help improve baking performance according to a study completed on CWRS flour by Cigi’s milling, analytical services and baking areas.

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Yulia Borsuk

Changes in dough rheological properties and bread baking quality were assessed at various time intervals under both ambient (room temperature) and frozen storage conditions over two years to determine the optimal flour storage period, says Yulia Borsuk, Technical Specialist in Baking Technology. She says the study may help millers and bakers who often deliberate what flour storage time delivers the best baking performance.

The project, which started in 2014, involved milling CWRS from that crop year in Cigi’s pilot mill. The flour was divided into two parts with half kept in sealed plastic containers in the pilot bakery and the rest frozen in Cigi’s blast freezer. The ambient flour was tested at two days, one week, three weeks, one month, then approximately every two months up to 25.5 months. The frozen flour was tested at the same intervals starting at one month.

The investigation showed that flour stored at ambient temperature after three weeks had better quality than freshly milled flour. Over time the flour displayed improved dough strength with longer mixing time, brighter colour and higher scores for bread quality characteristics. The frozen flour showed only minor changes in dough rheological properties and baking functionality.

Yulia notes that some changes in the ambient flour fluctuated at times, meaning that other factors may have impacted the quality other than storage time, while the frozen flour remained fairly consistent.

“Wheat quality changes due to storage time and storage conditions but when milled into flour it becomes even more sensitive to changes,” she says. “Wheat is a live commodity with enzymatic reactions happening all the time, affected by conditions like temperature and humidity. Climate, which can be so different in different countries, can impact wheat quality. High temperature and humidity can accelerate those changes.”

Consistency in flour quality is critical for bakers, especially in large industrialized bakeries where the processing is set up to operate in the most efficient way to ensure end-product quality, Yulia says. “Fluctuations in flour quality could interfere with this, causing issues at the bakery or plant. Information from this study can be useful to millers and bakers as it gives a better understanding of the changes in flour baking performance over time and optimization of the process on the milling or baking side can be done.”

She says that over the the period of the study the ambient flour continually increased in dough strength. “We found out that there was an improvement in flour baking quality after three weeks in storage which was also reflected in some dough rheological parameters tested in the lab with the farinograph and extensograph (analyzing flour properties, and stretch resistance and elasticity of the dough).

“Improvement in dough strength also meant longer mixing requirements as it basically takes more time to develop the gluten (protein) to its optimal consistency. This was shown in greater loaf volume and brighter internal crumb due to natural maturation of flour and enzymatic reactions.”

The study revealed that optimal baking performance of the ambient flour was maintained within the two-year period up to a certain point, she says. “Good baking performance relies on balanced dough properties which were negatively affected toward the end of the study period. At 19.5 months the dough became too resistant which impeded expansion of the dough during final proofing. Even with high protein content of the flour it was not reflected in a higher specific bread volume. It actually went down.”

Baking performance of the frozen flour was negligibly affected during the study period. The bread volume remained fairly stable and the dough retained balanced properties including extensibility and resistance while crumb brightness decreased.

The study results were presented in a poster entitled The Impact of Flour Storage Conditions on Dough Rheological Properties and Overall Baking Performance at the American Association of Cereal Chemists annual meeting last October in Savannah GA.