 IVES 9 IVES Conference Series 9 Influence of short-time skin maceration combined with enzyme treatment on the volatile composition of musts from fresh and withered fiano winegrapes

Influence of short-time skin maceration combined with enzyme treatment on the volatile composition of musts from fresh and withered fiano winegrapes

Abstract

AIM: The increasing market competitiveness is promoting the production of special dry wines with distinctive characteristics, obtained either from minor winegrape varieties and/or the inclusion of partially dehydrated grapes. With the aim of taking advantage of the grape quality traits in terms of aroma potential, short-time skin contact prior pressing in combination with the use of exogenous enzymes can facilitate the release of volatile organic compounds (VOCs) into the grape must. In addition, the possible presence of glycosidase activity enhances the hydrolysis of odourless glycosidically-bound precursors, which have a particular importance for non-aromatic grape varieties. [1,2] In this study, the effect of eight enzyme treatments with different single activity during short-term pre-fermentative maceration was investigated on the volatile composition of musts, obtained from both fresh and withered winegrapes cv. ‘Fiano’.

METHODS: The study was carried out on fresh or partially dehydrated (20% of weight loss) ‘Fiano’ white winegrapes from Campania region (southern Italy). For each sample, twenty-seven berry sets of 500 g each were randomly selected and crushed in presence of 10 mg/kg of potassium metabisulphite. Then, three berry sets were individually treated with pectin lyase (PL), polygalacturonase (PG), pectin methylesterase (PME), xylanase (XYL), arabinase (ARA), protease (PRO), β-glucanase (GLN), or β-glucosidase (GLU) enzymes at a dose of 10 mg/kg, homogenized and subjected to pre-fermentative maceration for 13 h at 12 °C. The other three berry sets were treated similarly but without enzyme addition (control). Subsequently, the musts obtained were separated from the skins and used for the determination of free and glycosidically-bound VOCs using solid-phase extraction followed by GC-MS analysis [3].

RESULTS: Regarding the free volatile fraction of musts, few compounds were influenced by the different enzyme treatments tested. This effect appeared to be more evident for glycosylated volatile compounds, for which the concentration of total compounds, aromatic alcohols, C6 alcohols, and certain terpenes (nerol and geraniol) significantly prevailed in musts from fresh grapes treated with PG. Moreover, samples from withered Fiano grapes treated with PG and ARA were characterized by higher contents of terpenes (cis-8-hydroxylinalool, nerol, geraniol, and α-terpineol), C6 alcohols (trans-2-hexenol and 1-hexenol), and benzenoids (eugenol).

CONCLUSIONS:

The addition of enzymes during short-term pre-fermentative maceration resulted to have effect mainly on the glycosylated volatile fraction of the musts obtained from fresh and withered grapes. In particular, exogenous enzyme activities such as PG exhibit major influence on the volatile profile of musts derived from fresh and withered ‘Fiano’ grapes, which could contribute to enhance the sensory perceived aroma of the resulting wines.

DOI:

Publication date: September 10, 2021

Issue: Macrowine 2021

Type: Article

Authors

Stefano Boz

University of Torino, Italy,Susana RÍO SEGADE, University of Torino, Italy Stefano BOZ, University of Torino, Italy Mattia MALABAILA, University of Torino, Italy Domen ŠKRAB, University of Torino, Italy Maria Alessandra PAISSONI, University of Torino, Italy Simone GIACOSA, University of Torino, Italy Luca ROLLE, University of Torino, Italy

Contact the author

Keywords

volatile compounds; enzymes; pre-fermentative maceration; fiano winegrapes

Citation

Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Advanced knowledge on grapevine row orientation is required to improve establishment, management and outcomes of vineyards on terroirs with different environmental conditions (climate, soil, topography) and in view of a future change to more extreme climatic conditions. The purpose of this study was to determine the combined effect of row orientation, plant water status and ripeness level on the physiological and viticultural reaction of Shiraz/101-14 Mgt.

Effects of mechanical leafing and deficit irrigation on Cabernet Sauvignon grown in warm climate of California

San Joaquin Valley accounts for 40% of wine grape acreage and produces 70% of wine grape in California. Fruit quality is one of most important factors which impact the economical sustainability of farming wine grapes in this region. Due to the recent drought and expected labor cost increase, the wine industry is thrilled to understand how to improve fruit quality while maintaining the yield with less water and labor input. The present study aims to study the interactive effects of mechanical leafing and deficit irrigation on yield and berry compositions of Cabernet Sauvignon grown in warm climate of California.

The effects of cane girdling on berry texture properties and the concentration of some aroma compounds in three table grape cultivars

The marketability of the table grapes is highly influenced by the consumer demand; therefore the market value of the table grapes is mainly characterized by its berry size, colour, taste and texture. Girdling could cause accumulation of several components in plants above the ringing of the phloem including clusters and resulting improved maturity. The aim of the experiments was to examine the effect of girdling on berry texture characteristics and aroma concentration.

Application of a fluorescence-based method to evaluate the ripening process and quality of Pinot Blanc grape

The chemical composition of grape berries at harvest is one of the most important factors that should be considered to produce high quality wines. Among the different chemical classes which characterize the grape juice, the polyphenolic compound, such as flavonoids, contribute to the final taste and color of wines. Recently, an innovative non-destructive method, based on chlorophyll fluorescence, was developed to estimate the phenolic maturity of red grape varieties through the evaluation of anthocyanins accumulated in the berry skin. To date, only few data are available about the application of this method on white grape varieties.

Different yield regulation strategies in semi-minimal-pruned hedge (SMPH) and impact on bunch architecture

Yields in the novel viticulture training system Semi-Minimal-Pruned Hedge (SMPH) are generally higher compared to the traditional Vertical Shoot Positioning (VSP). Excessive yields have a negative impact on the vine and wine quality, which can result in substantial losses in yield in subsequent vintages (alternate bearing) or penalties in fruit quality. Therefore yield regulation is essential. The bunch architecture in SMPH differs from VSP. Generally there is a higher amount but smaller bunches with lower single berry weights in SMPH compared to VSP.