Postharvest Treatment of Wood Biomass from a Large Collection of European Grape Varieties: Impact on the Selection of Polyphenol-Rich Byproducts

Abstract

Grape canes are viticulture byproducts representing a sustainable source of valuable bioactive polyphenols. However, varietal origin and postharvest treatment greatly influence the effective concentration of biomolecules, thus limiting industrial development. With the aim to develop grape cane extracts with high polyphenol contents, the selection of a specific grape variety combined with optimized postharvest treatment is the major determinant. A previously described postharvest treatment comprising cutting grapevine stalks of 0.5 cm length and storage at 15–20 °C over 2 weeks was applied on a selection of 44 grape varieties representative of the genetic diversity of the whole European collection and performing the screening of polyphenol contents. Varietal rankings according to major polyphenols (catechin, epicatechin, E-resveratrol, E-piceatannol, E-ϵ-viniferin, E-miyabenol C, ampelopsin A, E-vitisin B, hopeaphenol, and isophopeaphenol) were performed with and without the postharvest treatment. We observed that postharvest treatment greatly influenced the total polyphenol composition but also the ranking of polyphenol-rich varieties. This polyphenol screening of grape canes from a large collection of European varieties revealed the importance of postharvest treatment together with the selection of varieties to develop natural extracts based on grapevine wood biomass enriched with molecules with health benefits.

Vine Shoots as a Source of Trans-Resveratrol and ε-Viniferin: A Study of 23 Italian Varieties

“…In contrast, the Verdeca, Bianco d’Alessano, and Trebbiano varieties presented the lowest total stilbene concentration. In previous studies, a wide variability (from 2.5 to 4-fold) of total polyphenol amounts was already observed among different vine shoot varieties [ 18 , 30 , 37 ].…”

“…Considering the variety analysed in literature, vine shoots of Pinot Noir and Gewurztraminer have been reported as those with the highest content of stilbenes [ 15 , 18 , 29 , 30 ]. On the other hand, the extrinsic factors include the extraction method [ 26 ], storage time and temperature of the vine shoots, or various pre-treatments, such as the cutting length or thermal treatments, before stilbenes extraction [ 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Despite the available reports, the literature does not clarify univocally the effects of these heat treatments on stilbene quantities [ 26 , 39 , 40 ].…”

Identifying Major Drivers of Antioxidant Activities in Complex Polyphenol Mixtures from Grape Canes

“…From the thousands of existing European grape varieties, we used 44 grape varieties previously selected for their distribution among genetic clusters based on simple sequence repeats (SSR) [5]. A complete grape cane metabolic profile was performed on each grape variety in both ESI+ and ESI− modes using the molecular ion list previously described [19].…”

“…Large amounts of grape woods are pruned during winter, with a small part being recycled for composting, while added-value biomolecules could be valorized from this biomass. Consequently, a sustainable circular economy has been proposed based on the reuse of grape canes as a new source of dietary polyphenols to promote health benefits via antioxidant properties [3][4][5]. E-resveratrol, the "flagship molecule" from grapevine, exhibits antidiabetic, antitumor, anti-inflammatory, antiaging and neuroprotective activities [6][7][8], and E-piceatannol, an hydroxylated analogue of resveratrol, shows antioxidant, anti-inflammatory, antimutagenic, anticancer as well as antimicrobial activities [9,10].…”

“…It, at least, includes more than 40 polyphenols related to phenolic acids, flavonoids, procyanidins and stilbenoids as resveratrol oligomers (degrees of oligomerization [1][2][3][4]. This cocktail of polyphenols with varying proportions forms the chemotype of a grape variety and could likely influence the total antioxidant capacity of the extract [5,19].…”