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…

Grapevine productivity modelling in the Portuguese Douro Region

In Portugal, and particularly in the Demarcated Region of Douro (DDR), wine production has a great tradition, producing the unique and worldwide famous Port wine as well as other remarkably good table wines. In this study the impact of projected climate change to wine production is analysed for the DDR. A statistical grapevine yield model (GYM) is developed using climate parameters as predictors.

Elucidating the biological function of EPFL9 in grapevine roots

Epidermal Patterning Factors are a class of cysteine rich peptides known to be involved in many developmental processes. The role of EPF1, EPF2 and EPFL9 in controlling leaf stomata formation has been well described in model plants and cereals, and recently also in grapevine, while little is known about their activity in other organs. The aim of our study is to investigate whether VviEPFL9-2 can have a specific biological function in grapevine roots, where it resulted to be expressed. As grapevine is cultivated in the form of a grafted plant, we focused our study on the commonly used rootstock Kober 5BB (Vitis berlandieri x Vitis riparia). VviEPFL9-2 was edited in Kober 5BB plants using Agrobacterium tumefaciens transformation of embryogenic calli and the CRISPR/Cas9 technology. The phenotypic evaluation in greenhouse indicated that, as expected, the leaves of knock-out (KO) plants have a significant lower stomatal density compared to WT, associated with a lower stomatal conductance.

Understanding colloidal instability in white wine model solutions: A study focused on the effect of polysaccharides and salts onto bentonite efficiency

A white wine model solution (12% v/v ethanol, 4 g/L tartaric acid, pH 3.2) was used to assess wine colloidal instability as well as the influence of several wine components on bentonite performance in protein removal.

Defining gene regulation and co-regulation at single cell resolution in grapevine

Conventional molecular analyses provide bulk genomic/transcriptomic data that are unable to reveal the cellular heterogeneity and to precisely define how gene networks orchestrate organ development. We will profile gene expression and identify open chromatin regions at the individual cells level, allowing to define cell-type specific regulatory elements, developmental trajectories and transcriptional networks orchestrating organ development and function. We will perform scRNA-seq and snATAC-seq on leaf/berry protoplasts and nuclei and combine them with the leaf/berry bulk tissues obtained results, where the analysis of transcripts, chromatin accessibility, histone modification and transcription factor binding sites showed that a large fraction of phenotypic variation appears to be determined by regulatory rather than coding variation and that many variants have an organ-specific effect.

Study of the sensory dimension of the wine typicality related to a terroir and crossing with their viticultural and oenological characteristics

The typicality of a product can be characterized by properties of similarity in relation to a type, but also by the properties of distinction.