Study shows how cereal loses important acids during milling process


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An exterior view of Morrow Plots on Gregory Drive taken on November 30th, 2016.

By Brooke Eberle, Brand Manager

A new University study shows corn loses important nutrients, namely phenolic acids, when being processed into cornflakes.

Carrie Butts-Wilmsmeyer, one of the lead researchers of the study, said there are two types of phenolic acids: soluble and insoluble. Soluble acids are related to stopping aging-related diseases, like cancer and dementia, and are usually found in fruits and vegetables. Insoluble acids act as probiotics by promoting ideal environments for beneficial gut bacteria and are found in grains.

“The production of cornflakes from flaking grits is actually very simple and involves minimal food processing. Flaking grits are cooked in a sugar-salt solution, baked into a dough, rolled into a very thin layer, cut into cornflakes and then briefly toasted,” Butts-Wilmsmeyer said.

The team used this process with multiple grain samples and monitored the level of acids for each stage of the process. A video of the process paired with the research study was published in the “Journal of Visualized Experiments.”

The milling process of turning the corn into cornflakes is made up of two parts: dry milling and good processing. During the dry milling stage, the embryo and bran are separated from the endosperm. Then, the endosperm is milled into large flaking grits and sold to food processors to be made into cornflakes or other corn-based foods.

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Most of the phenolics are lost in during the milling process regardless of the sample because they are mostly located in the bran.

“This was a study where we emerged with both ‘good news’ and ‘bad news,’ so to speak. The bad news was that, regardless of the genotype, most of the phenolics were removed with the bran-containing co-products during dry milling and do not currently make it to many of our corn-based processed food products. The good news is that these phenolics are being physically removed and can be found in co-products; they’re not chemically degraded or permanently lost,” Butts-Wilmsmeyer said.

She said the best way to restore the acids during the milling process is to add a new processing step where phenolics could be extracted from the bran-containing co-products.

However, Butts-Wilmsmeyer said breakfast cereal is still a source of insoluble-bound phenolics, but whole grain or bran-containing foods tend to be better. The acids can also be found in fresh produce like mangos, berries, apples and other citrus fruits.

Still, she said she hopes to refine the milling process to allow breakfast cereal to be a food that supplies a high level of soluble phenolic acids by encouraging biofortification, the idea of breeding crops to increase their nutritional value.

“Our goal and the goal of the company that initially approached us with the idea of studying the phenolics in cornflakes is to find a way to economically capture this high content. It looks like biofortification might be the best route,” she said.

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