SENSORY DEFINITION OF A TECHNICAL UNAVOIDABLE TRANSFER OF AROMA COMPOUNDS VIA SEALING IN A BOTTLING LINE IN ORDER TO PREVENT PROSECUTION DUE TO FRAUDULENT AROMATIZATION OF A SUBSEQUENTLY FILLED WINE

Abstract

In 2020, 12% of all bottled German wines were aromatized, which may increase further due to rising popularity of dealcoholized wines. As sealing polymers of a bottling line absorb aroma compounds and may release them into regular wines in the next filling¹, this unintentional carry-over bears the risk to violate the legal ban of any aromatization of regular wine. However, following EU legislation, German food control authorities accept a technical unavoidable transfer of aroma compounds, if this is of no sensory significance. In order to prevent any legal consequences of aroma migration, we propose how to define the requested absence of sensory significance and how to improve cleaning in respect to aroma compounds.

Using a novel direct analysis of sealing polymers revealed that cleaning of the filler removed only 11–62% of seven studied aroma compounds which are commonly used to aromatize wines, including γ-decalactone, α-ionone or eugenol¹. High temperature of 85 °C revealed the largest cleaning effect, while chemical additives such as caustic soda or ozone exhibited only minor efficacy². Complete removal of absorbed aroma compounds from sealing was not achieved, making a later release into subsequently bottled wines still possible.

Odor detection thresholds were determined separately in water, model wine and white wine for the monitored aroma compounds. Applying the odor activity concept, we could show that migration of aroma compounds into the subsequently bottled wines were of no sensory relevance³.

Studying aroma migration in two industry scale bottling lines we could confirm the uptake of marker compounds into sealing polymers during bottling mulled or aromatized wines. Despite ineffective cleaning, aroma compounds migrating back into the subsequently bottled non-aromatized regular wines were way below their sensory thresholds. Sensory evaluation by a 2-out-of-5-test of the wine before and after bottling indeed revealed no significant difference.

In conclusion, despite migration of aroma compounds into sealing of a bottling line, cleaning and dilution effects in the subsequently filled wine prevented any aroma carry-over of sensory relevance. Thus, the analytical determination of “illegal” added aroma traces in a regular wine due to this technically unavoidable transfer, would not lead to legal prosecution. This legal evaluation could be a show case, how to apply the de-minimis concept to assess traces of pesticides or other contaminants into wine.