Effect of low temperature microwave treatment on lipid stability and antioxidant capacity of whole wheat flour

Abstract

The aim of this study was to inactivate the enzyme and improve the lipid stability of whole wheat flour (WWF) by microwave (MW) heating. With the temperature of MW treatment reaching 70 °C and the time extending to 20 min, the activities of lipase, lipoxygenase, peroxidase and polyphenol oxidase of WWF decreased by 64.29%, 37.45%, 32.1% and 27.13% respectively. During storage, free fatty acids decreased with the increase of MW treatment temperature (60, 65 and 70 °C) and time (5, 10, 15 and 20 min), however the peroxide value did not change significantly. The effects of MW treatment on the color and antioxidant capacity of WWF were also compared. The results showed that the color, total phenolic content and antioxidant capacity of the MW-stabilized WWF were similar to those of the control, but were able to significantly inhibit the deterioration of L* and a* values of WWF. In addition, MW treatment at 70 °C for 20 min could significantly reduce the free flavone content of WWF. Overall, MW treatment is a promising stabilization method, which can maintain WWF quality and antioxidant capacity, which is very important for industrial production.