Combined application of wounding stress and extrusion as an innovative tool to obtain carrot powders with modified functional properties

Abstract

Wounding stress induces the accumulation of phenolics in carrots. However, its effect on cell-wall constituents has not been studied. Extrusion generates modifications in high-fiber food matrices. In this study, the combined effect of wounding stress and extrusion on cell-wall constituents and functional properties of carrots was evaluated. Wounding stress was applied by shredding carrots and storing the tissue (48 h/15°C). The stressed tissue (wounding stress carrot, WSC) was dehydrated and then extruded at temperature, 60 or 100°C, and screw configuration, continuous or expansion. Extrudates were milled and analyzed for cell-wall constituents and other physicochemical parameters. Cellulose content increased (112%) as a response to wounding. Furthermore, extrudates obtained from WSC showed higher content of cell-wall components. For instance, insoluble and total lignin content increased (54–84%) with extrusion conditions. Furthermore, WSC showed higher oil absorption index and lower water solubility index (WSI); whereas extrudates showed the highest WSI.