The addition of functional ingredient resistant starch (RS3) in wheat flour changes the rheological properties of the flour, according to a study conducted by South Korean researchers.

Researches Sa-Ra Hong and Byoungseung Yoo tested the consistency and flow of wheat flour with the added resistant starch at various concentrations.

According to the researchers, the modifications in wheat flour are dependent on the concentration of the resistant starch present in the flour; however, previous studies on RS3 have been limited only to examining the impact on pasting and gel properties.

The study, titled Effect of resistant starch (RS3) addition on rheological properties of wheat flour’, reveals that the significant change can be noticed with 20% RS3, or at the highest concentration.

RS3, one of the four other strains of resistant starches, is generally used in food service industry to manufacture bakery products, and is believed to increase functionality, improve cholesterol metabolism, reduce the risk of colon cancer and regulate blood sugar.

The researchers further said that RS3 is beneficial for indigestibility and thermal stability, which could provide functional benefits as a food ingredient.

The resistant starch is formed when starch-containing foods are cooked and cooled such as in bread, cornflakes and cooked-and-chilled potatoes or retrograded high amylose corn.

Resistant starches are categorised into four classes – RS1, RS2, RS3 and RS4, and various studies prove that RS2 and RS3 resistant starches from high amylose corn promote intestinal/colonic health through their fermentation and action as pre-biotic fibers.

Resistant starch is considered to be the third type of dietary fiber, as it delivers a few benefits of insoluble fiber and some of the benefits of soluble fiber.

The study was funded by Dongguk University Research Fund and was published in the journal Starch – Stärke.