Baking experts know that flours made from soft wheat contribute to good cake quality. But what isn’t well known is precisely which characteristics of soft wheat most affect that quality, says Byung-Kee Baik, a research leader with the U.S. Department of Agriculture’s Agricultural Research Service (ARS). He adds that soft wheat traits vary widely depending on the wheat variety and growing environment.
This hasn’t been well studied, he explains, partly due to the absence of a cake baking test that uses nonchlorinated flour instead of chlorinated flour. Milling companies are turning to heat treatments to replace flour chlorination because while chlorinated flour—which allows bakers to make dough with less flour and more sugar—is still legal in the United States, it’s banned in many countries due to health concerns about the chemicals such as chlorine gas that are commonly used for chlorination. Gaining a better understanding of wheat grain and nonchlorinated flour performance for cake baking will help millers and bakers choose suitable wheat strains and flours, according to Baik.
“Not all soft wheat is going to make good quality cake,” says Baik, who leads the ARS Corn, Soybean & Wheat Quality Research Unit in Wooster, Ohio.
So Baik developed an experimental cake baking test using nonchlorinated flour and used it to study flour characteristics and cake baking performance. The test is currently being assessed by the Cereals & Grains Association Technical Committee. “Through this study, we can prove that some characteristics are a lot more important than others,” he observes.
For the study, Baik used 20 soft winter wheat varieties grown in the Eastern United States with a large range of grain and flour characteristics. The varieties were analyzed for grain density, kernel hardiness, and protein content, and then milled.
One of the unique things about Baik’s research is its focus on the viscosity of the cake batter. Batter viscosity is very important, he says, because the batter needs to have a certain level of thickness to retain flour particles and create a consistent weight so that the finished cake has a uniform structure. Without good viscosity, he explains, the structure will be uneven—heavy particles will sink to the bottom, making the bottom of the cake very dense while the upper portion is fluffy and soft.
Most of a regular cake batter’s viscosity comes from cake’s other ingredients, like sugar, Baik says, so there needed to be another way to test the role of unchlorinated wheat in viscosity. For that reason, he created two simple flour batters—one just flour and water and the other containing water, a sucrose solution, and a higher proportion of flour in order to isolate flour’s effects on viscosity. These two simple batters, where flour plays a bigger role, are effective batter viscosity tests, he says, and so can be used to predict the quality of flour for cake baking.
Surprisingly, the researchers found that wheat protein content and the level of damaged starch content aren’t predictors of cake baking quality. Kernel hardiness, another important trait of soft wheat, is also not a good predictor. This is likely because Eastern soft wheat has low kernel hardiness and low protein content. “Once protein content is lower than a certain level, it’s no longer a major factor,” says Baik.
Follow-up research could examine the importance of flour particle size, which is also thought to be significant for cake quality, he says. But further reducing particle size and increasing starch damage by regrinding may have a negative effect on flour quality.
“On one side, you’ll improve flour quality for baking a cake by reducing particle size by grinding, but at the same time you’ll have increased damaged starch content, which is known to negatively affect cake baking quality,” he explains.