High Hydrostatic Pressure Processing of Whole Carrots: Effect of Static and Multi-Pulsed Mild Intensity Hydrostatic Pressure Treatments on Bioactive Compounds.

In this study, the effects of static and multi-pulsed mild-intensity high hydrostatic pressure (HHP) treatments (60 or 100 MPa, ~23 °C) on the extractability and accumulation of phenolics and carotenoids in whole carrots were evaluated. HHP treatments were applied for the time needed to reach the desired pressure (come-up-time, CUT) either as a single pulse or multi-pulse (2P, 3P, and 4P). Likewise, a single sustained treatment (5 min) applied at 60 or 100 MPa was evaluated. Individual carotenoids, free and bound phenolics were quantified after HHP treatment and subsequent storage (48 h, 15 °C). As an immediate HHP response, phenolic extractability increased by 66.65% and 80.77% in carrots treated with 3P 100 MPa and 4P 60 MPa, respectively. After storage, CUT 60 MPa treatment accumulated free (163.05%) and bound (36.95%) phenolics. Regarding carotenoids, total xanthophylls increased by 27.16% after CUT 60 MPa treatment, whereas no changes were observed after storage. Results indicate that HHP processing of whole carrots at mild conditions is a feasible innovative tool to enhance the nutraceutical properties of whole carrots by increasing their free and bound phenolic content while maintaining carotenoid levels. HHP treated carrots can be used as a new functional food or as raw material for the production of food and beverages with enhanced levels of nutraceuticals.

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

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 ß-carotene.