Abstract
Pulsed electric field (PEF) processing affects the cell permeability of plant tissue. This technology is capable of enhancing mass transfer and releasing valuable compounds (e.g. juice, health-promoting phytochemicals) from plant cells at low electric fields. This study aimed to assess the influence of PEF (1033 square wave bipolar 20 μs pulses of 1.4 kV/cm at a frequency of 50 Hz for a total treatment time of 20.66 ms) on the release of anthocyanins from grapes (Vitis vinifera L. cv. Merlot) after 48 h of PEF treatment and on its potential to protect Caco-2 cells from H2O2-induced oxidative stress. Merlot anthocyanins were characterized and quantified using LC-MS. To assess the bioprotective potential, cell viability was measured using 3-(4, 5-dimethythiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay that indicates the mitochondrial metabolic activity. A significant increase in the release of anthocyanins was obtained immediately after PEF. After 48 h, PEF had facilitated the release of malvidin, delphinidin and petunidin glucosidic derivatives of anthocyanins. Because of the increase in amount and types of Merlot anthocyanins released due to PEF within 48 h, the obtained grape juice was more effective in protecting Caco-2 cells from oxidative damage. This finding provides evidence that PEF can increase the release of anthocyanins as well as delivering bioactivity important in the field of functional foods.