Comparative study of colour, pasting and antioxidant properties of different wheat cultivars as affected by toasting and roasting

Abstract

Wheat has been reported to contain a variety of bioactive compounds which have health benefits. The bioactive compounds, however, are affected by the different processing conditions applied to wheat flour during the manufacture of different products. Milled wheat is used to produce a variety of baked products, but the effect of toasting and roasting before milling has not been examined. Therefore, the effects of mild (toasting) and strong (roasting) heat treatments on the Hunter Lab colour, pasting and antioxidant properties of flours from commercially important wheat cultivars grown in India were investigated. Antioxidant properties including total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (AOA), metal chelating activity (MCA) and ABTS+ scavenging activity were studied. Both heat treatments resulted in a reduction in bulk density (BD) and Hunter L* values. However, Hunter a* and b* values were increased. The AOA, MCA and ABTS+ scavenging activity of flours increased after both treatments, while TFC was decreased and TPC was increased after toasting but decreased after roasting. All pasting parameters except pasting temperature increased with toasting but decreased after roasting. Flour from cv.WHD-943 showed the highest AOA, TPC and ABTS+ scavenging activity both before and after the two heat treatments.