IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 HPLC and SEC analysis on the flavonoids and the skin cell wall material of Merlot berries reveals new insights into the study of the phenolic maturity

HPLC and SEC analysis on the flavonoids and the skin cell wall material of Merlot berries reveals new insights into the study of the phenolic maturity

Abstract

Anthocyanins and tannins contribute to important sensorial traits of red wines, such as color and mouthfeel attributes. Despite the evolution of flavonoids during berry ripening has been extensively studied and the properties of skin and flesh cell wall material (CWM) to bind tannins were described, the mechanism determining the reduction of unpleasant astringency in the last phases of ripening remained uncertain. In this regard, the present research was aimed to better understand the factors involved in the phenolic maturity by a detailed evaluation of the flavonoid characteristics and the CWM properties, in the last weeks before harvest and at harvest. The study was conducted in 2014 and 2015 in a Merlot vineyard located in the hills near Bologna (north of Italy). The analysis of flavonoids and skin CWM was performed on berries sampled 20 and 10 days before harvest and at harvest. Exhaustive extractions were conducted to analyze total anthocyanins and tannins (skin and seed separately), while a model hydroalcoholic solution was used for their extractable portion. Moreover, binding reactions between the CWM and an enological seed tannin were performed to evaluate the magnitude of tannin precipitation and the composition of the  tannins remained in solution.HPLC analysis showed the increase of total and extractable anthocyanins during ripening, while no change was found in the concentration, composition and mean degree of polymerization (mDP) of skin and seed tannins. Also, the composition of CWM did not change significantly, but the tendency of proteins to increase until the harvest was noticed in both years. Moreover, CWM bound increasing quantity of the enological seed tannin during ripening, favoring, in particular, the precipitation of the tannins with higher mDP and of the galloilated forms, which are reported to be the compounds more involved in the perception of unpleasant astringency. The analysis performed by SEC confirmed that CWM bound preferentially the tannins of high molecular mass (MM), while lower amounts of medium MM tannins and negligible quantities of low MM tannins interacted with CWM. Our results confirmed that more ripen berries may release higher amounts of anthocyanins and allowed us to hypothesize that CWM may play a role in the decrease of astringency which is associated with the progression of ripening.

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Allegro Gianluca1, Bautista-Ortín Ana-Belén2, Gómez-Plaza Encarna2, Pastore Chiara1,  Valentini Gabriele1, Mazzoleni Riccardo1 and Filippetti Ilaria1

1Department of Agricultural and Food Sciences – University of Bologna, Viale Fanin 46, 40127, Bologna, Italy
2Departamento de Tecnología de Alimentos, Nutrición y Bromatología – Universidad de Murcia (Spain)

Contact the author

Keywords

anthocyanins, astringency, ripening, tannins, Vitis vinifera

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Studio dell’ambiente viticolo attraverso la parametrazione (punto di incrocio) delle curve di maturazione delle uve (pinot nero, oltrepo’ pavese pv italia settentrionale – 45° parallelo Nord)

Sono stati presi in considerazione alcuni dati agrometeorologici dell’Oltrepò Pavese (temperature e piovosità degli ultimi 80 anni) e gli studi delle curve di maturazione condotti in zona sul Pinot nero da spumante negli anni (1988-1991, 1999-2000, 2006-2008), si nota che l’aumento progressivo negli anni delle temperature attive (indice di Winkler) ha determinato un anticipo dell’invaiatura, definita dal parametro “punto di incrocio” (intersezione delle funzioni di zuccheri ed acidità nel tempo), con conseguente anticipo della data di vendemmia di circa 12-15 gg.

Vacuum distillation of Muscaris pomace: temperature effects on aroma composition

The consumption of wine in traditional wine-producing countries like Italy, Spain, and France is decreasing.

Drought affects vineyard soil microbiome: approach to select micro-organisms adapted to drought

Climate transition with frequent heat waves and long drought periods threatens grapevine productivity and wine quality in the Mediterranean regions. Microorganisms are known to contribute to plant fitness and to stimulate plant resilience against biotic and abiotic factors.
In this work, it was assessed the impact of long-term drought on soil microbiome associated to grapevine in open field in Alentejo, renowned Portuguese wine region.
Soil and plant tissues of drought tolerant Syrah cultivar exposed to three irrigation levels (100%- FI, 50%-DI ETc; rain-fed–NI) for 5 years were sampled for two years (2022-2023). Metabarcoding analysis of soil bacteria (16S V4 rRNA) and fungi (ITS sub-region) were integrated with soil physiochemical properties and leaves´ physiological data. Pre-dawn leaf water potential and stomatal conductance confirmed the imposed drought scenarios. Even though, α- and β-diversity of prokaryotic and eukaryotic microbial communities differed more by season than water availability, samples clustered according to soil water content and pH (p<0.05). Fungal communities show higher differences in the structure across treatments than bacteria. In 2023, 16 bacterial against 61 fungal ASVs were significatively different in abundance between NI and FI. Beijerinckiaceae, Bradyrhizobiaceae (Alphaproteobacteria) and Nocardioidaceae, Streptomycetaceae (Actinobacteria) families resulted to be significatively more abundant in NI, while Ascomycota, Basidyomicota and Mortierellomycota are the most important fungal phyla in NI. With culturomics data, this study aims to gather insights into how soil microbiome is remodelled under drought and contribute to select bacterial and fungal taxa with potential to mitigate drought stress in vineyards.

Unexpected relationships between δ13C, water deficit, and wine grape performance

Water nutrition is crucial for wine grape performance. Thus soil investigation aims at characterizing spatial and temporal variability of available water. A possible strategy

Chemical profiling and sensory analysis of wines from resistant hybrid grape cultivars vs conventional wines

Recently, there has been a shift toward sustainable wine production, according to EU policy (F2F and Green Deal), to reduce pesticide usage, improve workplace health and safety, and prevent the impacts of climate change. These trends have gained the interest of consumers and winemakers. The cultivation of disease resistant hybrid grape cultivars (DRHGC), known as ‘PIWI’ grapes can help with these objectives [1]. This study aimed to profile white and red wines produced from DRHGC in South Tyrol (Italy). Wines produced from DRHGCs were compared with conventional wines produced by the same wineries. The measured parameters were residual sugars, organic acids, alcohol content, pigments and other phenolics by LC-QqQ/MS, colorimetric indexes (CIELab); and volatile profiles (HS-SPME-GCxGC-ToF/MS [2]).