Macrowine 2021
IVES 9 IVES Conference Series 9 Effects of temperature on the aroma composition of hydrolysates from grape polyphenolic and aroma fractions (PAFs)

Effects of temperature on the aroma composition of hydrolysates from grape polyphenolic and aroma fractions (PAFs)

Abstract

AIM: The aim is to assess whether fast anoxic aging hydrolysis (75ºC x 24 h) can satisfactorily predict aroma developed from grape aroma precursors at milder conditions (50ºC x 5 weeks).

METHODS: Twelve different phenolic and aromatic fractions (PAFs) extracted, six from Grenache and the other six fromTempranillo, were reconstituted in model wine and aged in duplicate in two different anoxic conditions. Mild conditions were at 50º for 5 weeks in complete anoxia. Harsh conditions were at 75ºC for 24 hours in complete anoxia. Hydrolysates were further extracted and analysed by four different volatile analysis: esters and major alcohols were analysed by GC-FID, free norisoprenoids, terpenoids, phenols and lactones by GC-MS, Strecker’s aldehydes by GC-MS and varietal thiols were analysed by GC-NCI-MS.

RESULTS: A total of 32 compounds was quantified with RSD between 2 and 15%. Some compounds have concentrations very relevant from the sensory point of view, like TDN (1,1,6-trimethyl-1,2-dihydronaphthalene), β-damascenone, massoia lactone and 3-mercaptohexanol (3MH). Grenache samples presented higher concentrations than Tempranillo samples, of 4-vinylguaicol, 4-vinilphenol, linalool, β-citronellol and TDN.Most key aroma compounds can be satisfactorily predicted from the accelerated hydrolysis at 75ºC. Levels of eugenol, massoia lactone, 3MH, β-ionone and vainillin derivatives, released at 75ºC are significantly correlated with those found after 5 weeks at 50ºC, and the slopes do not significantly differ from 1. Levels of β-damascenone and α-terpineol in samples hydrolysed at 75ºC, were however, lightly higher than those found at 50ºC, but were strongly correlated. On the contrary, levels of Riesling acetal were a little higher at 50ºC, but were also strongly correlated.However, levels of TDN, linalool and geraniol in both hydrolytical conditions were poorly correlated. Data suggest that linalool and geraniol can be best represented by the accelerated hydrolysis, while TDN are best represented by the milder hydrolysis.

CONCLUSIONS

Harsh hydrolysis at 75ºC represents a good compromise which makes it possible to get a satisfactory representation of the grape aroma potential. Labile compounds, such as linalool and geraniol are in fact best measured at this temperature. However, long-aging aroma compounds, such as TDN, will require longer hydrolysis times and other relevant aroma compounds with different precursor molecules, such as 4-vinylguaiacol, are also poorly predicted at 75ºC.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Elayma Sánchez Acevedo

Laboratory for Aroma Analysis and Enology (LAAE), Universidad de Zaragoza, Instituto Agroalimentario de Aragón (IA2) (UNIZAR-CITA), Zaragoza (Spain),VICENTE FERREIRA Laboratory for Aroma Analysis and Enology (LAAE), Universidad de Zaragoza, Instituto Agroalimentario de Aragón (IA2) (UNIZAR-CITA), Zaragoza (Spain)  RICARDO LÓPEZ Laboratory for Aroma Analysis and Enology (LAAE), Universidad de Zaragoza, Instituto Agroalimentario de Aragón (IA2) (UNIZAR-CITA), Zaragoza (Spain)

Contact the author

Keywords

acid hydrolysis, aroma, phenolic and aromatic fractions (PAFs), Grenache, Tempranillo

Citation

Related articles…

Machines and fire: developing a rapid detection system for grapevine smoke contamination using NIR spectroscopy and machine learning modelling

Bushfires are a common occurrence throughout Australia and their incidence is predicted to both rise and increase in severity due to climate change. Many of these bushfires occur in areas close to wine regions, which receive different levels of exposure to smoke. Wine produced from smoke-affected grapes are characterised by unpalatable smoky aromas such as “burning rubber”, “smoked meats” and “burnt wood”. These smoke tainted wines are unprofitable and result in significant financial losses for winegrowers.

Energy optimization of the Charmat-Martinotti refermentation process

The european union has estimated that energy consumption for wine production is about 1,750 million kwh per year, of which 500 million kwh is attributable to italy. In recent years, Italy has emerged as the world’s leading wine producer with about 50 million hectoliters per year. About 20 percent (9.8 million hectoliters) of Italian wine is marketed after refermentation according to the Charmat-Martinotti method.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

Monitoring small-scale alcoholic fermentations using a portable FTIR-ATR spectrometer and multivariate analysis

Although some wine production processes still rely on post-production evaluation and off-site laboratory analysis, the new winemaking industry is aware of a need for a better knowledge of the process to improve the properties of the final product. Thus, more and more wineries are interested in incorporating quality-by-design (QbD) strategies instead of postproduction testing because of the possibility to early detect deviations in fermentation or any other wine process. This would allow to detect unwanted situations and eventually to ‘readjust’ the process, thus minimizing rejects.

Effect of the addition of peptidic hydrolysates from grape pomace by-products to red wines in warm regions

High temperatures typical of warm climates cause the colour of red wines to become increasingly unstable over time.