Sequential application of postharvest wounding stress and extrusion as an innovative tool to increase the concentration of free and bound phenolics in carrots

•Carrots were subjected to wounding stress and extrusion processing.•Phenolic and carotenoid profiles were characterized in the samples.•Wounding stress increased the content of free and bound phenolics.•Extrusion increased the wound-induced accumulation of free and bound phenolics.•Trans-cis isomerization of β-carotene was detected due to extrusion. Postharvest wounding stress in carrots induces the accumulation of phenolics, whereas extrusion generates modifications in the nutritional profiles of food matrixes. In the present study, the sequential application of wounding stress and extrusion on total free and bound phenolics as well as on carotenoid profiles of carrots was evaluated. Wounding was applied by shredding carrots and storing the tissue (48 h, 15 °C). The stressed-tissue was dehydrated and extruded at 63 °C or 109 °C and at continuous or expansion screw configurations. Extrudates were milled and sieved before phytochemical analysis. Wounding increased total free (288.1%) and bound (407.6%) phenolic content, whereas the carotenoid content was unaltered. The free and bound phenolics that showed the highest increase due to wounding were the chlorogenic (579.8%) and p-coumaric (390.9%) acids. Extrusion, at 109 °C under expansion screw configuration, further increased the wound-induced accumulation of total free (296.6%) and bound (22.1%) phenolics and induced trans-cis isomerization of β-carotene.