tannins and methyl-jasmonate

The western flower thrips,

Topics: Acetates; Animals; Cyclopentanes; Flavonoids; Flowers; Glutathione Transferase; Lignin; Oxylipins; Phaseolus; Phenols; RNA Interference; Tannins; Thysanoptera

The effect of the application of benzothiadiazole (BTH) and methyl jasmonate (MeJ) at veraison on the phenolic composition of grapes from three varieties (Monastrell, Syrah and Merlot) was studied during the ripening period, using HPLC techniques to measure flavonols, anthocyanins and tannins.. The effects of the treatments differed in the three varieties, and the maximum concentration of phenolic compounds was not always reached at the end of the ripening period but some days before harvest. At the end of ripening both treated Syrah grapes only differed from control grapes in the flavonol concentration, whereas MeJ-treated Merlot grapes presented higher anthocyanin and skin tannin contents than the control and BTH-treated grapes. Only the anthocyanin content was significantly higher in treated Monastrell grapes at the moment of harvest.. The results indicate that the moment of elicitor treatment should be more studied since differences between treated and control grapes were, in general greater several days before harvest in all three varieties. © 2016 Society of Chemical Industry.

Topics: Acetates; Aerosols; Agrochemicals; Anthocyanins; Antioxidants; Chromatography, High Pressure Liquid; Crop Production; Crops, Agricultural; Cyclopentanes; Flavonols; Fruit; Humans; Nutritive Value; Oxylipins; Phenols; Pigments, Biological; Plant Epidermis; Spain; Species Specificity; Spectrometry, Mass, Electrospray Ionization; Spectrophotometry, Ultraviolet; Tannins; Thiadiazoles; Vitis

Stilbene-enriched wine is considered to be an interesting new food product with added value due to its potential health-promoting properties. Stilbene concentration in grape is highly variable and rather scarce. However, it can be increased by stress treatments. For this reason, numerous pre- and postharvest grape treatments, and some combinations of them, have been tested to maximize stilbene content in grapes. In the present manuscript, Syrah grapes were treated with (i) methyl jasmonate (MEJA), (ii) ultraviolet light (UVC), and (iii) methyl jasmonate and ultraviolet light (MEJA-UVC) and compared with untreated grapes. Afterward, winemaking was developed. Wine achieved by combination of both treatments (MEJA-UVC) contained significantly higher stilbene concentration (trans-resveratrol and piceatannol) than its respective control (2.5-fold). Wine quality was improved in color-related parameters (color intensity, L*, a*, b*, ΔE*, anthocyanins, and tannin). Moreover, MEJA-UVC wines obtained the highest score in sensorial analysis. To the best of our knowledge, this is the first time that pre- and postharvest treatments are combined to increase stilbenes in wine.. The effect of treatment combination (methyl jasmonate and UVC light) on grape and wine was evaluated. Our results highlight the positive effect of the treatments in stilbene content, color parameters, and sensorial analysis. Moreover, added-value by-products were achieved.

Topics: Acetates; Anthocyanins; Color; Cyclopentanes; Fruit; Humans; Odorants; Oxylipins; Plant Growth Regulators; Resveratrol; Stilbenes; Tannins; Taste; Ultraviolet Rays; Vitis; Wine