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…

Assessment of the impact of actions in the vineyard and its surrounding environment on biodiversity in Rioja Alavesa (Spain)

Traditional viticulture areas have experienced in the last decades an intensification of field practices, linked to an increased use of fertilisers and phytosanitary products, and to a more intensive mechanization and uniformization of the landscape. This change in management has sometimes led to higher rates of soil erosion andloss of soil structure, fertility decline, groundwater contamination, and to an increased pressure of pests and diseases. Additionally, intensification usually leads to a simplification of landscapes, of particular concern in prestigious wine grape regions where the economical revenue encourages the conversion of land use from natural habitats to high value wine grape production. To revert this trend, it is necessary that growers implement actions that promote biodiversity in their vineyards. The aim of this study is to assess the impact of the implementation of cover crops, vegetational corridors, dry stone walls and vineyard biodiversity hotspots estimated through the study of arthropods. The work has been carried out in four vineyards in Rioja Alavesa belonging to Ostatu winery, where these infrastructures were implemented in 2020. The presence and diversity of arthropods was studied by capturing them at different times in the season and at different distances from the infrastructure using pit-fall traps in the soil and yellow, white and blue chromatic traps at the canopy level. This is a preliminary study in which all adult insects were sorted to the taxonomic level of order and Coleoptera were classified to morphospecies. The results obtained show that there is a relationship between the basic characteristics of the vineyard and the arthropods captured, with a positive effect, although also dependent on the vineyard, of the presence of infrastructure.

AGEING REVEALS THE TERROIR OF AGED RED BORDEAUX WINES REGARDLESS OF THE VINTAGES! TARGETED APPROACH USING ODOROUS COMPOUNDS LEVELS INCLUDING TERPENES AND C13 NORISOPRENOIDS

The chemistry of wine is notably complex and is modified by ageing of the bottles. The composition of wines is the result of vine production (under the influence of vintage, climate and soils); yeast production (under the influence of juice composition and fermentation management); lactic bacteria production (under the influence of young wine composition and malolactic fermentation management); and of the ageing process either in vats, barrels or bottles or both. The composition is linked to the quality perceived by consumers but also to their origin, sometimes associated to the “terroir” concept.

How much does the soil, climate and viticultural practices contribute to the variability of the terroir expression?

When considering the application of a systemic approach to assess the intrinsic complexity of agricultural production, the following question immediately arises

Optimizing disease management in the Rioja wine region: a study on Erisiphe necator and the Gubler-Thomas model

Erisiphe necator is endemic in the Rioja Appellation of Origin. Vine growers exert significant effort to protect their crops, given the economic losses this disease causes. Different studies have shown that using Gubler-Thomas Model (GTM) can reduce treatments by up to 20% compared to a full-time protection strategy. This reduction is achieved by optimizing applications based on temperature variations in late spring and summer when the disease’s conidial stage is active.

Recent advances in measuring, estimating, and forecasting grapevine yield and quality

Grapevine yield and fruit quality are two major drivers of input allocation and, ultimately, revenue for grape producers. Because yield and fruit quality vary substantially from year-to-year and within a single block, opportunities exist for optimization via precision management activities that could lead to more profitable and sustainable grape production. Here, we review recent advances in the techniques and technology used to measure, estimate, and forecast grapevine yield and fruit quality. First, we discuss direct “measurement” of yield and quality (i.e. ground-truth data generation), with an emphasis on potential for scalability and automation. Second, we discuss technology and techniques that do not directly measure yield and quality, but use correlated measurements for their estimation.