Aroma profiling of Shine Muscat grape provides detailed insights into the regulatory effect of gibberellic acid and N-(2-chloro-4-pyridinyl)-N-phenylurea applications on aroma quality.

As plant growth regulators, gibberellic acid (GA3) and CPPU [forchlorfenuron, N-(2-chloro-4-pyridinyl)-N-phenylurea] are widely used in the production of table grapes. However, how these compounds regulate the aroma quality remains unclear. By measuring free and bound aroma compounds in Shine Muscat grapes from eight groups during whole growth period, GA3 and CPPU were both found to significantly promote the synthesis of acyclic monoterpenes and (E)-2-hexenal, and double applications were found to further increase the aroma compound contents. On the other hand, GA3 and CPPU obviously promoted the expansion of berries, and the effect of promoting the synthesis of aroma compounds was largely diminished. In conclusion, free compound concentrations in berry were almost unaffected by GA3 and CPPU. From the perspective of aroma compounds, a highly concerted interplay was observed for terpenes, and bound compounds exhibited higher correlations than those of free compounds. In addition, 17 compounds could be used as markers that indicated the developmental timing of berries.

Evolution of green leaf volatile profile and aroma potential during the berry development in five Vitis vinifera L. Cultivars.

Green leaf volatiles (GLVs), play important roles in the green and fresh aroma characteristics of grape berries. The evolution of GLV profiles regarding the varietal difference during grapevine phenological ripening is not well understood. This study generated the GLV profiles of five Vitis vinifera L. cultivars ('Cabernet Sauvignon,' 'Cabernet Franc,' 'Cabernet Gernischt,' 'Chardonnay,' and 'Sauvignon Blanc') at five ripening stages. GLVs were distinctive at different E-L stages for each grape variety. (E)-2-hexen-1-ol, 1-hexanol, and hexanal were the dominant components in all mature berries. In terms of total GLV content, all varieties reached the maximum at maturity in the 2019 vintage, and the total GLV content was higher in mature Sauvignon Blanc and Cabernet Sauvignon grapes. In the 2020 vintage, the total GLV content in Chardonnay and Sauvignon Blanc berries rapidly accumulated at veraison and peaked before harvest. The present results could help winemakers create a good balance of wine aroma.

Dynamic changes in monoterpene accumulation and biosynthesis during grape ripening in three Vitis vinifera L. cultivars.

Monoterpenes are important aroma components in grapes and wines. We analyzed the free and bound monoterpene profiles and the transcript levels of terpenoid biosynthesis genes in Vitis Vinifera cvs. Muscat Hamburg, Riesling, and Sauvignon Blanc grapes at five ripening stages. Principal component analyses revealed that the three cultivars had different free monoterpene profiles at harvest and the early stage of ripening. In all cultivars, the total bound monoterpene contents were higher than the free monoterpene contents during grape ripening. The changes in monoterpene profiles in different grape varieties were correlated with the transcript levels of some VviTPS and VviGT genes. In Riesling, the VviGT14 and VviUGT88A1L1 transcript levels were related to geraniol glucoside accumulation. In Muscat Hamburg, the VviPNLGl1, VviPNLGl2, and VviPNLGl4 transcript levels were related to linalool accumulation. Understanding the dynamic changes in monoterpene accumulation and biosynthesis will allow winemakers to devise strategies to improve grape and wine aromas.

"Hemping" the drinks: Aromatizing alcoholic beverages with a blend of Cannabis sativa L. flowers.

Cannabis sativa L. is a multi-purpose crop, traditionally used for fibre and seed production, whose cultivation is permitted in Europe for varieties complying with the Δ9-tetrahydrocannabinol 0.2% threshold. To face the need for a more sustainable agriculture system, the circularization of the crop industries is of the utmost importance. For hemp, the present study proposes the use of flowers, normally regarded to as crop residues, as further exploitable by-products. A French, 'Futura 75', and a Ukrainian, 'Uso 31', cultivar flowers were used for the extraction of the essential oil (EO) and as flavouring agents of two artisanal alcoholic beverages (a beer and a liqueur). The compositions of the EOs and the beverage headspaces were characterized by GC-MS, then subjected to multivariate statistical analysis. The enrichment of the flavour bouquet was more evident for the liqueur, which retained more hemp-derived compounds. The beer maintained its volatile aroma compounds profile, slightly enriched with more balsamic notes.

Effect of cluster zone leaf removal on monoterpene profiles of Sauvignon Blanc grapes and wines.

Monoterpenes contribute to the varietal aromas of grapes and wines. We determined the effects of cluster zone leaf removal on the monoterpene profiles of Sauvignon Blanc grape berries and wines, and on the expression of key genes in the terpenoid pathway. Leaf removal at two intensities (half basic, 50%; full basic, 100%) was conducted at two weeks before veraison, veraison, and two weeks after veraison. Half basic leaf removal increased the pH and decreased the tartaric acid content in grapes and wines. The concentrations of most free- and bound-form monoterpenes in grapes were increased by early leaf removal. The total monoterpene contents were increased in wines in the defoliation treatments, but were significantly lower in wines from the full basic leaf removal treatments than in wines from the half basic leaf removal treatments. The defoliation treatments resulted in increased transcript levels of some key genes in terpene biosynthesis (VvPNLinNer1, VvPNLinNer2, VvPNLNGl1, VvPNLNGl2, and VvUGT88A1L1).