Modification of wine phenolic profiles by gibberellic acid application in 'Cabernet Gernischt' grapevines before anthesis.

Vitis vinifera L. 'Cabernet Gernischt' grapes from the Yantai wine region of China usually form dense clusters and contain low phenolic content. We applied five concentrations (ranged from 5 to 25 mg L-1 ) of gibberellic acid (GA3 ) to 'Cabernet Gernischt' before anthesis to decrease cluster compactness in two consecutive vintages. Yield indices, grape maturity, and wine phenolic compounds were determined. GA3 application significantly reduced cluster compactness, bunch weight, and yield per vine, but it did not significantly improve fruit ripening. The levels of total phenolics, total tannins, and total anthocyanins in wine were enhanced by GA3 application, with 10 and 15 mg L-1 GA3 treatments consistently producing a significant increase in the concentrations of mavidin, cyanidin, and their derivatives. Specifically, trans-resveratrol was consistently significantly increased by 15 mg L-1 GA3 application. Principal component analysis of phenolic compounds demonstrated the differences among wines produced from GA3 treatment groups and the control. Overall, wine phenolic profiles could be significantly modified by application of low concentrations of GA3 before anthesis. Application of high levels of GA3 is not recommended due to significant yield decrease. © 2022 Society of Chemical Industry.

Song J ，Zhang A ，Gao F ，Liang H ，Li M ，Zhang J ，Wang G ，Qu H ，Cheng S ，Ruan S ，Li J ... -  《-》

Reduced nitrogen fertilization from pre-flowering to pre-veraison alters phenolic profiles of Vitis vinifera L. Cv. Cabernet Gernischt wine of Yantai, China.

Nitrogen (N) fertilization is important for grape growth and wine quality. Unreasonable N fertilizer application affects wine growth and has a negative impact on wine quality. Therefore, it is essential to address the mismatch between N application and wine composition. To regulate vine growth and improve grape and wine quality, Cabernet Gernischt (Vitis vinifera L.) grapevines were subjected to lower levels of N, compared to normal N supply treatments, during the grape growing seasons of 2019 and 2020 in the wine region of Yantai, China. The effects of reduced N application from pre-boom to pre-veraison on vine growth, yield and composition of grapes, and dry red wine anthocyanin and non-anthocyanin phenolic compound content were studied. We found that reduced N application significantly decreased dormant shoot fresh mass and yield. However, the effect of N application on fruit ripening depended on the season. Nitrogen-reduction treatment significantly improved wine phenolic parameters, including total phenolics, tannins, and anthocyanins, and enhanced most of the individual anthocyanins and some non-anthocyanin phenolics, especially stilbenes, including piceatannol, trans-resveratrol, and polydatin, regardless of the season. Overall, our findings highlight the importance of reducing N application during the grape growing season in order to modify the wine phenolic profiles.

Song J ，Zhang A ，Gao F ，Li M ，Zhao X ，Zhang J ，Wang G ，Hou Y ，Cheng S ，Qu H ，Ruan S ，Li J ... -  《-》

Co-winemaking with Vitis amurensis Rupr. "Beibinghong" enhances the quality of Vitis vinifera L. cv. Cabernet Gernischt wine.

In some wine regions of China, Cabernet Gernischt (CG; Vitis vinifera L.) grape berries usually exhibit low pigment content and titratable acidity, and low sensory quality of the resulting wine. The aim of this study was to evaluate co-winemaking of CG wines using the red grape cultivar Beibinghong (BBH; Vitis amurensis Rupr.) at different proportions in terms of alcohols, phenolic compounds, and sensory properties of the wines. The results showed that the co-winemaking wines contained a similar content of higher alcohols, whereas the methanol content increased with an increase in BBH proportion, although this was still corresponded with the national standard. Significantly higher levels of titratable acidity were observed in co-winemaking wines at the ratio of 6:4 and 5:5, compared with monocultivar CG wines. All co-winemaking wines, except CG:BBH (9:1) wine, showed significantly higher levels of total anthocyanins, total phenolics, total tannins, and total flavan-3-ols. Further, individual phenolics, primarily diglucoside anthocyanins and non-anthocyanins (trans-ferulic acid, myricetin, viniferin, trans-caffeic acid, 3,4-dihydroxybenzoic acid), as important contributors to wine color intensity, permitted the differentiation of the wines via principal component analysis. In most cases, co-winemaking wines exhibited higher scores of the 10 sensory attributes on color, aroma, mouthfeel, and overall quality compared with monocultivar wines. Co-winemaking CG wines with BBH at 7:3 ratio demonstrated the highest scores of color intensity, aroma intensity, aroma quality, and overall quality. The results indicate that co-winemaking with V. amurensis grape variety may be useful to enhance V. vinifera wine quality by modifying wine composition. PRACTICAL APPLICATION: Cabernet Gernischt (CG) is the predominant grape cultivar used to prepare premium-quality wine in China; however, in some wine regions, CG wines have low levels of pigment and titratable acidity, and low sensory quality. Co-winemaking with another native grape cultivar, Beibinghong (BBH), which is characterized by a higher content of anthocyanins and acidity, provided sufficient experimental evidence of adjustments in the Vitis vinifera wine composition leading to improved wine sensory quality.

Song J ，Zhang A ，Cheng S ，Li X ，Zhang Y ，Luan L ，Qu H ，Ruan S ，Li J ... -  《-》

Effects of gibberellic acid (GA(3) ) application before anthesis on rachis elongation and berry quality and aroma and flavour compounds in Vitis vinifera L. 'Cabernet Franc' and 'Cabernet Sauvignon' grapes.

Gibberellic acid (GA3 ), a plant-growth regulator, is often used to obtain enlarged table grape berries and induce seedlessness in them. However, the effects of GA3 on rachis elongation and bunch compactness have seldom been reported in wine-grape production. We assessed the effects of GA3 spraying on wine-grape inflorescences and bunches and their practical implications for viticulture in the Jiaodong Peninsula, China. Various GA3 concentrations were sprayed on field-grown Vitis vinifera L. 'Cabernet Franc' (CF) and 'Cabernet Sauvignon' (CS) grapevines before anthesis in the Jiaodong Peninsula, China, in 2015 and 2016. Inflorescence length during berry development was measured, and flavonoids and aroma compounds in the fruit were detected by high-performance liquid chromatography - mass spectrometry (HPLC-MS) and gas chromatography - mass spectrometry (GC-MS), respectively. For both cultivars, 50 and 100 mg L-1 GA3 caused significant elongation of the rachis, whereas there was no significant effect on inflorescence growth and berry seed number. Anthocyanin, flavonol, and flavan-3-ol levels in mature berries were not significantly influenced by GA3 spraying, whereas C13 -norisoprenoids were modified. The application of 50-100 mg L-1 GA3 prior to grapevine anthesis caused elongation of inflorescences and bunches, and eased cluster compactness in CF and CS, and no negative effects were observed on the yield and seed numbers. The concentration and composition of flavonoids and most aroma compounds were not influenced, except that the norisoprenoids were increased by 50 mg L-1 GA3 applications. © 2020 Society of Chemical Industry.

Gao XT ，Wu MH ，Sun D ，Li HQ ，Chen WK ，Yang HY ，Liu FQ ，Wang QC ，Wang YY ，Wang J ，He F ... -  《-》

Effects of gibberellin applications before flowering on the phenotype, ripening, and flavonoid compounds of Syrah grape berries.

Vitis vinifera L. cv. Syrah grapevines in most Chinese viticulture regions generally have compact clusters that increase the susceptibility to diseases and inhibit coloration of the inner berries. Gibberellic acid (GA3 ) is a plant growth regulator that is widely used during grape cultivation to elongate the rachis, control fruit set, and decrease cluster compactness. In this study, Syrah grapevines were treated with GA3 before flowering in 2019 and 2020 to determine the optimal GA3 treatment concentrations and times for decreasing bunch compactness, while minimizing the negative effects on the wine grape cluster weight. Pre-flowering GA3 applications at 3, 5, and 7 mg L-1 , especially treatment at 20 days before flowering, decreased Syrah grape bunch compactness by decreasing the fruit set rate and promoting bunch elongation, with minimal adverse effects on the healthy grape cluster weight in both years. The 7 mg L-1 GA3 treatment at 20 days before flowering significantly increased reducing sugar, total phenolic, tannin, and total anthocyanin contents of Syrah grape berries in 2019 and 2020. Moreover, high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, hierarchical cluster, and principal component analysis results indicated GA3 applications before flowering (3, 5, and 7 mg L-1 ) significantly affected the accumulation of different anthocyanins in Syrah grape berries. Notably, the application of 7 mg L-1 GA3 at 20 days before flowering resulted in the highest anthocyanin content. Pre-flowering gibberellin application can decrease bunch compactness and improve the quality of Syrah grape berries. These findings reflect the potential utility of gibberellin treatments for decreasing cluster compactness and increasing the quality of wine grapes. © 2022 Society of Chemical Industry.

Xie S ，Liu Y ，Chen H ，Yang B ，Ge M ，Zhang Z ... -  《-》