New pulsed electric fields approach to improve the blanching of carrots
Leire Astráin-Redín, Javier Raso, Ignacio Ãlvarez, Bente Kirkhus, Ane Meisland, Grethe Iren A. Borge, Guillermo Cebrián
Abstract
Pulsed Electric Fields (PEF)-ohmic is one of the most recently proposed alternatives for the application of ohmic heating in order to provide a more uniform and faster heating of food. In this study, the application of PEF-ohmic (1.33 kV/cm, 100 Hz) for the blanching of carrot cylinders was explored, and the inactivation of the peroxidase enzyme was mathematically simulated and experimentally validated. The effect of this PEF-ohmic treatment on carrot texture and its effect on the in vitro bioaccessibility of β-carotene were also determined. The best heating uniformity was achieved when PEF-ohmic was applied to carrots immersed in water at a starting temperature of 80 °C and after applying brief heating-up treatments (90 s). However, a holding heating phase (85 °C for 50 s) was required to achieve complete peroxidase inactivation after the heating-up PEF phase. The blanching time was reduced by 60% without negatively affecting the texture of the carrots and slightly increasing (3.9 %) the bioaccessibility of the β-carotene. Overall, PEF could be an effective system for rapid and volumetric blanching of vegetables.