terclim by ICS banner
IVES 9 IVES Conference Series 9 PHOTOCHEMICAL DEGRADATION OF TRYPTOPHAN IN MODEL WINE: IMPACT OF HEAVY METALS AND OXYGEN ON 2-AMINOACETOPHENONE FORMATION

PHOTOCHEMICAL DEGRADATION OF TRYPTOPHAN IN MODEL WINE: IMPACT OF HEAVY METALS AND OXYGEN ON 2-AMINOACETOPHENONE FORMATION

Abstract

The wine industry worldwide faces more and more challenges due to climate change, such as increased dryness in some areas, water stress, sunburn and early harvesting during hot summer temperatures¹. One of the resulting problems for the wine quality might be a higher prevalence of the untypical aging off-flavor (ATA)². A substance, which Rapp and Versini made responsible for ATA, is the 2-aminoace-tophenone (2-AAP)³. 2-AAP in wine causes a naphthalene, wet towels, wet wool, acacia flower or just a soapy note⁴. The formation of the substance occurs via the degradation of tryptophan and the trypto-phan metabolite indole-3-acetic acid. The formation of 2-AAP is promoted by abiotic stress factors such as drought, low nitrogen content and high temperature, and by microorganisms via riboflavin, known as a photosensitizer5. In this study, the influence of other abiotic factors, namely oxygen and heavy me-tals, on the light-induced degradation of tryptophan to 2-AAP was investigated. Model wine with 0.53 µmol/l riboflavin was treated with UV-C light to stimulate tryptophan degradation. A linear increase in the intensity of UV-C light exposure caused a linear increase of 2-AAP. Increasing oxygen in the model wine supported the production of 2-AAP verifying that tryptophan degradation via riboflavin follows an oxidative pathway. Indeed, 2-AAP production decreased by 81 % when oxygen was reduced from saturation to anoxic conditions. It was also found that the presence of heavy metals led to a significant reduction of 2-AAP: 0.1 mmol/l Fe²+ decreased 2-AAP by 63 %, and 0.1 mmol/l Cu²+ decreased 2-AAP by 32 %. This observation can be explained by the Fenton reaction which requires Fe²+ and/or Cu²+ to produce – in this case – acetaldehyde from ethanol. It is suggested that the Fenton reaction acts as a competitive reaction to the photosensitized production of 2-AAP. As a lateral observation, the model wine in this study turned yellow after being UV-C radiated. The LC-MS signal suggested the substance lumichrome; its signal increased with the more yellow color of the model wine. Accordingly, riboflavin could not only act as a photosensitizer but also degrade itself after exposure to light.

 

1. Santos, J. A. et al. (2020). A Review of the Potential Climate Change Impacts and Adaptation Options for European Viticulture. Applied Sciences, 10(9), 3092. https://doi.org/10.3390/app10093092
2. van Leeuwen, C. et al. (2020). Recent advancements in understanding the terroir effect on aromas in grapes and wines. OENO One, 54(2). https://doi.org/10.20870/oeno-one.2020.54.4.3983 
3. Rapp, A., Versini, V., Ullemeyer, H. (1993). 2-aminoacetophenone: Causal component of ‘untypical aging flavour’ (‘naphthale-ne note’, ‘hybrid note’) of wine. Vitis, 32(1), 61-62. https://doi.org/10.5073/vitis.1993.32.61-62
4. Alpeza, I. et al. (2021). Atypical aging off-flavour and relation between sensory recognition and 2-aminoacetophenone in Croatian wines. Journal of Central European Agriculture, 22(2), 408-419. https://doi.org/10.5513/JCEA01/22.2.3103
5. Hühn, T. et al. (1999). Release of undesired aroma compound from plant hormones during alcoholic fermentation. Vitiv. Enol. Sci., 54, 105-113.

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Article

Authors

Svetlana Cvetkova¹, Sarah Edinger¹, Daniel Zimmermann¹ und Dominik Durner¹

1. Weincampus Neustadt/DLR Rheinpfalz, Institute for Viticulture and Enology, Breitenweg 71, D-67435 Neustadt an der Weinstraße, Germany

Contact the author*

Keywords

2-aminoacetophenone, iron, oxygen, riboflavin

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

PHENOLICS DYNAMICS OF BERRIES FROM VITIS VINIFERA CV SYRAH GRAFTED ON TWO CONTRASTING ROOTSTOCKS UNDER COMBINED SALINITY AND WATER STRESSORS AND ITS EFFECT ON WINE QUALITY

Wine regions are getting warmer as average temperatures continue raising affecting grape growth, berry composition and wine production. Berry quality was evaluated in plants of Vitis vinifera cv Syrah grafted on two rootstocks, Paulsen (PL1103) and SO4, and grown under two salinity concentrations (LS:0.7dS/m and HS:2.5dSm-1) in combination with two irrigation regimes (HW:133% and CW:100%), being the seasonal water application 483mm (control, 100%). Spectrophotometer measurements from berry skin during veraison and harvest stages and from “young” wine samples, were indicative of the stressors effect and the mediation of the rootstocks. At veraison (i) total phenolics content were high under LSHW (0.7dSm-1 and high water conditions) for SO4 and PL1103.

Read More

CONSENSUS AND SENSORY DOMINANCE ARE DEPENDENT ON QUALITY CONCEPT DEFINITIONS

The definition of the term “quality” in sensory evaluation of food products does not seem to be consensual. Descriptive or liking methods are generally used to differentiate between wines (Lawless et al., 1997). Nevertheless, quality evaluation of a product such as wine can also relate to emotional aspects. As exposed by Costell (2002), product quality is defined as an integrated impression, like acceptability, pleasure, or emotional experiences during tasting. According to the ‘modality appropriateness’ hypothesis which predicts that wine tasters weigh the most suitable sensory inputs for a specific assess- ment (Freides, 1974; Welch & Warren, 1980), the nature of the quality definitions may modulate sensory influences.

Read More

EVALUATION OF A SEAWEED EXTRACT OF RUGULOPTERYX OKAMURAE AGAINST ERYSIPHE NECATOR IN GRAPEVINE

Powdery mildew, caused by Erysiphe necator, is a widespread disease that causes high economical losses in viticulture. The main strategy to control the disease is the recurrent application of sulphur based phytochemical compounds. However, in order to reduce their accumulation in the environment and promote the sustainability of the sector, the European Commission has applied restrictions to the number of pesticide treatments and the maximum quantity of fungicides to be applied in viticulture. Seaweeds, in particular macroalgae, are marine resources rich in sulphated polysaccharides with bio-protective potential for the plant, representing an environmentally-friendly alternative approach for sustainable wine production.

Read More

IMPACT OF MANNOPROTEIN N-GLYCOSYL PHOSPHORYLATION AND BRANCHING ON WINE POLYPHENOL INTERACTIONS WITH YEAST CELL WALLS

Yeast cell walls (CWs) may adsorb wine components with a significant impact on wine quality. When dealing with red wines, this adsorption is mainly related to physicochemical interactions between wine polyphenols and cell wall mannoproteins. However, mannoproteins are a heterogeneous family of complex peptidoglycans including long and highly branched N-linked oligosaccharides and short linear O-linked oligosaccharides, resulting in a huge structural diversity.

Read More

DETERMINATION OF MINERAL COMPOSITION IN CV. TERAN (VITIS VINIFERA L.) RED WINE AFFECTED BY PRE-FERMENTATIVE MASH COOLING, HEATING, SAIGNÉE TECHNIQUE AND PROLONGED POST-FERMENTATIVE MACERATIONS

This study aimed to determine mineral composition in red wine obtained from cv. Teran (Vitis vinifera L.), autochtonous Croatian grape variety. Six different vinification treatments, including the control treatment (7-day standard maceration), were performed to study the effects of: 48-hour pre-fermentative mash cooling (8 °C) followed by prolonged post-fermentative maceration of 13 days (C15), 28 days (C30), and saignée technique (juice runoff) proceeded with prolonged post-fermentative maceration of 13 days (CS15); and effect of 48-hour heating (50 °C) followed by prolonged post-fermentative maceration of 13 days (H15) and 28 days (H30) on macro- and microelements in wine.

Read More