Changes in concentration of volatile compounds in response to defoliation of Muscat of Alexandria grapevines grown under a traditional farming system

Abstract

373Linalool is a monoterpene, which exhibits floral and spicy aromas as well as a variety of pharmacological effects, including antioxidant, anti-inflammatory, and cardiovascular. Wine flavor is highly dependent on the chemical compounds of berries. The objective of this study was to evaluate the concentration of volatile compounds, especially linalool, in grapes (Vitis vinifera L.) 'Muscat of Alexandria' grown under different cluster light exposure. Four defoliation treatments were applied at veraison, and changed the light environment at the fruit zone. Severe defoliation (T1): leaves were manually removed from the 1 st to the 8 th node of each shoot, partial defoliation (T2): leaves were manually removed from the 1 st to the 4 th , semi-shaded clusters (T3): un-trimmed vines were covered with an 80% shade netting; and (T4) control treatment with non-intervention during season 2014-2015. Free terpenes were extracted using headspace solid-phase microextraction (HS-SPME), and the concentration of volatile compounds was determined using gas chromatography coupled to a flame ionization detector (GC-FID). The study was conducted in two different locations of the Itata Valley in Chile. Linalool concentration was more prevalent in treatments with higher cluster exposure. The treatment with the highest defoliation showed a linalool concentration 40% higher than the control treatment. Higher levels of defoliation in grapevines grown under a traditional farming system result in an increased concentration of volatiles compounds, particularly monoterpenes, where Cerro Verde and Pinihue reached linalool concentrations of 19.1 and 21.7 μg L -1 , respectively. These results revealed important differences in the behavior of the synthesis of linalool.

Resurgence of minority and autochthonous grapevine varieties in South America: a review of their oenological potential

“…Currently, the interest in elaborating monovarietal, sparkling, and late harvest wines from this variety is increasing due to its interesting aromatic composition and freshness . Muscat grape cultivars are known for the strong aromatic properties that they confer to wines, mainly due to their high presence of terpenes, which present low odor thresholds .…”

“…152 Currently, the interest in elaborating monovarietal, sparkling, and late harvest wines from this variety is increasing due to its interesting aromatic composition and freshness. 23 Muscat grape cultivars are known for the strong aromatic properties that they confer to wines, mainly due to their high presence of terpenes, which present low odor thresholds. 153 Belancic et al 154 reported that Moscatel de Alejandría and Moscatel Rosada presented similar total free terpenoids with a concentration close to 2100 μg L−1 154 , although Moscatel de Alejandría contained abundant concentrations of total bound terpenols.…”

“…According to the odor activity values (OAV), the most active compounds in commercial Piscos were isovaleric acid, isoamyl alcohol, 1-heptanol, linalool, hotrienol, -ionone, isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, isoamyl acetate, ethyl heptanoate, and cis-3-hexenyl acetate. 156 Pascual et al 23 reported that linalool was the most prevalent volatile compound in Moscatel de Alejandría clusters exposed to sun. These authors reported that treatment with the highest defoliation of Moscatel de Alejandría vines allowed an important increase in the linalool concentration compared with a control treatment.…”

“…15,[17][18][19] In recent years, a new productive trend has gradually been introduced in the world wine industry, favoring the production and preservation of minority grapevine varieties. 15,16,[20][21][22][23][24][25][26][27][28][29] In contrast to the general trend of producing wine from globally disseminated grapevine varieties, associated with the French paradigm, there is a slight tendency to increase the number of studies of minority or autochthonous grapevine varieties. The aim is to seek distinct products, different from the current homogenized wine production.…”

Location effects on ripening and grape phenolic composition of eight ‘Carignan’ vineyards from Maule Valley (Chile)

“…The accumulation of flavonols in grapes is activated in response to treatments with UV and sunlight (Haselgrove et al, 2000). Light interception at fruit zone is determined by the training system, and its management can increase sunlight exposure improving grape quality (Pascual et al, 2017). In this way, temperature appears to have a less influence on flavonol synthesis, compared to sunlight (Makris et al, 2006;Flamini et al, 2013).…”