Effect of Combining Pulsed Electric Fields with Maceration Time on Merlot Grapes in Protecting Caco-2 Cells from Oxidative Stress

Abstract

The objective of this study was to investigate the effect of different maceration times (0, 2, 4, 8 and 14 days) after pulsed electric field (PEF) processing (1.5 kV/cm, either at 15 or 70 kJ/kg) on the release of anthocyanins from Merlot grapes (Vitis vinifera) and the bioprotective potentials of grape juice against H 2 O 2 -induced oxidative stress using human intestinal Caco-2 cell culture model. Cell viability, lactate dehydrogenase membrane leakage and nitric oxide production in Caco-2 cells were used as biomarkers to indicate general cellular health and integrity that ultimately represent the bioprotective potentials of grape juice. The results showed that PEF at 70 kJ/kg was the most effective in accelerating the release of anthocyanins from grape skin. Furthermore, the amount and the type of anthocyanins being released varied as a result of combined effect of PEF processing intensity and maceration time. Linear correlations between anthocyanins and the bioprotective capacity markers (R 2 = 0.4-0.8) were found. Compared to the untreated Merlot, PEF treatment either at 15 or 70 kJ/kg reduced the maceration time from 14 to 8 and 2 days, respectively, to achieve similar degree of bioprotective effect. This implies the possibility of using combined PEF and maceration time to tailor the profile of bioactive compounds with the same bioprotective potentials.

Evolution of Polyphenolic Compounds and Sensory Properties of Wines Obtained from Grenache Grapes Treated by Pulsed Electric Fields during Aging in Bottles and in Oak Barrels

“…Improving the degree of extraction of polyphenols during the maceration-fermentation stage of red winemaking has been one of the most widely investigated applications of pulsed electric fields (PEF) in recent years. Several research groups working with different grape varieties have demonstrated that a PEF treatment applied to grapes before the maceration-fermentation stage allows for a reduction of the contact time of grape skins with the fermenting must, or helps to obtain wines with higher polyphenolic content [2][3][4][5][6]. This effect is attributed to a phenomenon called electroporation, which involves an alteration of cell membrane permeability as a consequence of the application of an external electric field [7].…”

Effects of pulsed electric field technology on the nutritional value and biological function of plant food

“…For Yellow Solar carrots, which had a low total carotenoid content, PEF significantly increased the carotenoid content (Leong et al, 2016a;Rezaeinezhad et al, 2022). Leong et al (2016b) also found that PEF treatment shortened the immersion time and improved the protection against H 2 O 2 oxidative stress in Vitis Vinifera. Leong et al also evaluated the effect of PEFs on the release of anthocyanins and the health effects of Pinot noir grape juice; Pinot noir grapes treated with PEF were able to produce substances with stronger antioxidant activity and exhibited greater protection against oxidative stress (Leong et al, 2016c;Chen et al, 2023).…”