To identify wine grape cultivars (Vitis vinifera) with superior color properties for wine production, the anthocyanin composition and color characteristics of fourteen cultivars and their wines were investigated. Grapes and wines from 'Dornfelder', 'Dunkelfelder', and 'Malbec' cultivars exhibited significantly higher total phenolic contents. At harvest, 'Dornfelder' grapes and wines exhibited the highest total anthocyanin contents, with values of 249.94 mg/kg in grapes and 1686.76 mg/L in wines, significantly higher than other cultivars. PCA and PLS-DA analyses identified malvidin-3-O-(trans-6-O-coumaryl)-glucoside as a common differential metabolite in both grapes and wines across all cultivars. Correlation analysis revealed that non-acylated anthocyanins (r = 0.68) have a more significant impact than acylated anthocyanins (r = 0.28) on color chromatic diversity in grapes and wines (P < 0.05). These findings suggest that wines produced from 'Dornfelder' grapes are particularly valuable for their superior color properties and high individual anthocyanin contents. This study addresses a gap in comparative anthocyanin analysis among cultivars and provides valuable insights for grape growers and winemakers seeking to optimize grape selection for improved wine quality.

To investigate the impact of genetic factors on wine aroma, wines made from 22 clones of five grape varieties (Vitis vinifera L.) were used to analyze the volatile compounds by headspace solid phase microextraction gas chromatography mass spectrometer (HS-SPME-GC–MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS). Results showed that 52 and 49 aroma compounds were identified from 22 clones of wines by two technologies, respectively. Esters were the most abundant compounds, followed by alcohols and aldehydes. The aroma profiles demonstrated significant varietal and clonal diversity, the clones with the highest aroma compound content were CH VCR6, PN VCR20, CS VCR11, ML VCR101, and CF 678. Partial least squares discriminant analysis (PLS-DA) identified decanoic acid, 1-heptanol, diethyl succinate, ethyl octanoate, and octanal as key biomarkers for distinguishing 22 clones of wines. Our results revealed that white wine CH VCR6 and red wine CS VCR11 possessed the most complex aromas. These findings address the research gap concerning the genetic determinants of wine aroma, highlighting the significance of grape variety and clone selection in developing wines with desirable sensory attributes.

Green leaf volatiles (GLVs) are important in giving grape a fresh and green aroma. But the changes in GLVs during the phenological development of grapevines are not well known. This study analyzed the GLVs and transcription levels of associated biosynthetic genes in six grape species from the Loess Plateau region at five stages of maturation. Thirteen GLVs were detected, showing unique patterns for each grape type at various growth phases. The primary components in six grapes were (E)-2-hexenal, (E)-2-hexen-1-ol, and hexanal. With the exception of Cabernet Franc in 2019, the overall GLV contents of the six types generally increased during growth and development, peaking or stabilizing at harvest. And Sauvignon Blanc, Cabernet Gernischt, and Cabernet Sauvignon exhibited higher total contents among the varieties. PLS-DA analysis revealed 3-hexenal’s high VIP scores across two years, underscoring its critical role in grape variety classification. Correlation analysis revealed a strong positive correlation between the levels of hexanal, 1-hexanol, (E)-2-hexen-1-ol, (Z)-3-hexenyl acetate, nonanal, and (E, E)-2,6-nonadienal and the expression of VvHPL and VvAAT genes in the LOX-HPL pathway. Specifically, VvHPL emerges as a potential candidate gene responsible for species–specific differences in GLV compounds. Comprehending the changing patterns in the biosynthesis and accumulation of GLVs offers viticulturists and enologists the opportunity to devise targeted strategies for improving the aromatic profile of grapes and wines.

This study investigated the effects of γ-polyglutamic acid (PGA) and alginic acid (ALA) on grapes and wines. Marselan grapes were utilized to assess the accumulation and synthesis of phenolic compounds and antioxidant activity. The 0.35 % (v/v) PGA (PGA2) significantly enhanced the antioxidant activity of both grapes and wines in both years. Overall, treatments with 0.45 % (v/v) PGA (PGA3), 0.45 % (v/v) ALA (ALA3), and 0.25 % (v/v) ALA (ALA1) notably increased the total phenolic and anthocyanin content in both grapes and wines. Among these, PGA3 treatment significantly upregulated the levels of Delphinidin-3-O-(6-acetyl)-glucoside, Cyanidin-3-O-(6-acetyl)-glucoside, Peonidin-3-O-glucoside, and Malvidin-3-O-(trans-6-O-coumaryl)-glucoside in both years. Additionally, PGA3 treatment elevated the expression of the VvPAL, VvCHS, VvDFR and VvLDOX genes across both years. In contrast, ALA3 and ALA1 treatments increased anthocyanin content by upregulating the expression of VvCHS, VvF3’H and VvUFGT genes. In summary, PGA3 treatment significantly enhanced the phenolic compounds and antioxidant activity in both grapes and wines. These findings demonstrate the potential of PGA and ALA as biostimulants to significantly enhance grape and wine quality in viticulture.

Green leaf volatiles (GLVs) are important in giving grape a fresh and green aroma. But the changes in GLVs during the phenological development of grapevines are not well known. This study analysed the GLVs and transcription levels of associated biosynthetic genes in six grape species from the Loess Plateau region at five stages of maturation. Thirteen GLVs were detected, showing unique patterns for each grape type at various growth phases. The primary components in six grapes were (E)-2-Hexenal, (E)-2-Hexen-1-ol, and Hexanal. With the exception of Cabernet Franc in 2019, the overall GLV contents of the six types generally increased during growth and development, peaking or stabilizing at harvest. And Sauvignon Blanc, Cabernet Gernischt, and Cabernet Sauvignon exhibited higher total contents among the varieties. Correlation analysis revealed a strong positive correlation between the levels of Hexanal, 1-Hexanol, (E)-2-Hexen-1-ol, (Z)-3-Hexenyl acetate, Nonanal, and (E, E)-2,6-Nonadienal and the expression of VvHPL and VvAAT genes in the LOX-HPL pathway. Specifically, VvHPL emerges as a potential candidate gene responsible for species-specific differences in GLV compounds. Comprehending the changing patterns in the biosynthesis and accumulation of GLVs offers viticulturists and enologists the opportunity to devise targeted strategies for improving the aromatic profile of grapes and wines.