Comparison of Ozone and UV-C Treatments on the Postharvest Stilbenoid Monomer, Dimer, and Trimer Induction in Var. ‘Superior' White Table Grapes

Abstract

Postharvest treatment of seedless white table grapes (var. 'Superior') with different gas ozone concentrations (3.88 and 1.67 g/h) for 1, 3, and 5 h induced an increase in stilbenoid biosynthesis [trans-resveratrol, piceatannol, and viniferinas (resveratrol dehydrodimers and dehydrotrimers)] during storage at 22 degrees C and 95% relative humidity. The maximal resveratrol concentration was reached after 2 days of storage, and this amount was similar to that induced by optimized UV-C treatments (1 min, 510 W, 40 cm). Although similar resveratrol concentrations accumulated in grapes after both UV-C and O3 treatments (maximum ozone production and time), the ozone treatment was more efficient in inducing viniferins accumulation in grape berries. A sequence in the biosynthesis of stilbenoids was observed, starting with the resveratrol monomer, continuing with the resveratrol dehydrodimers epsilon-viniferin and delta-viniferin, and ending with four different resveratrol dehydrotrimers. These trimers were different from alpha-viniferin, a trimer previously reported to be induced in grapes after biotic and abiotic stresses. Two alpha-viniferin isomers were also detected in the ozone-treated grapes, although at very low concentrations that prevented their quantification.

Regulation of stilbene biosynthesis in plants

“…Schubert et al (1997) revealed that Vst1, an STS gene from grapevine, was transcriptionally regulated by ozone application, and the Vst1 promoter sequences, essential for the ozone-induced expression, have been identified. In accordance with the data, it has been shown that post-harvest ozone treatments of table grapes enhanced accumulation of resveratrol and pterostilbene (Sarig et al 1996) and t-resveratrol, piceatannol, and viniferins (González- Barrio et al 2006) in amounts similar to those induced by ultraviolet-C (UV-C) treatments.…”

The stilbene profile in edible berries

“…The influence of the combination of ozone and UVtreatment on stilbenes content was also investigated (González-Barrio et al 2006). The results showed that UV-C was generally much more efficient (shorter treatment time) in inducing resveratrol content than ozone.…”

Effects of Ultraviolet C Irradiation on Stilbene Biosynthesis in Vitis vinifera L. cv. Cabernet Sauvignon Berry Skins and Calli

“…ε-Viniferin is a resveratrol dehydrodimer that is not widespread in non-infected plants. ε-Viniferin can be stimulated by stresses such as UV-C irradiation (González-Barrio et al, 2006) and fungal inoculation, including with Plasmopara viticola (Pezet et al, 2004) and Aspergillus carbonarius (Bavaresco et al, 2008).…”