Effects of microwave heating of wheat on its functional properties and accelerated storage.

Abstract

The effect of microwave heating wheat grains (700W for 0-60s) on gluten, farinograph, pasting properties and baking (steamed bread and biscuit) of flour was studied. The lipase (LA) and lipoxygenase (LOX) activities of the microwave-treated wheat were monitored, and the accelerated storage at 35°C of whole wheat flour was also investigated. The results showed that the gluten, farinograph properties and viscosity were influenced to a small extent when microwave treatment time was less than or equal to 20s and the temperature of the grains was less than or equal to 56°C. Texture profile analysis indicated that steamed bread made from wheat treated by microwave for 20s was softer and of better quality. Microwave treatment for longer periods (≥30s) increased the temperature ≥68°C, that damaged the gluten and made wheat unsuitable for making steamed bread; however, suitable for making food with lower gluten requirements, such as biscuits. The results obtained from enzyme activity and accelerated storage experiments demonstrated that microwave treatment could inactivate LA and LOX and extend the shelf-life.