The companies found elastomer sealing components to be a relevant factor in aroma carryover and that the selection of the optimum sealing material is crucial in preventing the transfer of flavours from one filling process to the next, and the following ones.
Eva Beierle, development engineer, aseptic and process technology at Krones, understands the aroma carryover issue from the bottlers' point of view. She says: "One trend in the latest beverages is toward increasingly intense flavours. This poses challenges, since beverages with high concentrations of flavours naturally tend to leave perceptible traces of aroma in the bottling lines. Working with Trelleborg Sealing Solutions has given us a deep understanding of how to avoid unacceptable aroma carryover during filling."
Together with Krones, Trelleborg Sealing Solutions performed tests to understand where and why aroma carryover occurs in bottling plants. The elastomer materials used in sealing components in filling machines, which are in contact with beverages, proved to be a significant factor. The aromas used for beverages, especially when used in high concentrations, diffuse into elastomer materials. The seals can then release the absorbed aromas even after thorough rinsing between beverage filling processes.
Analysis of sealing materials showed that seals made of ethylene propylene diene rubber (EPDM) absorbed more aroma molecules, while fluorocarbon (FKM) materials demonstrated significantly better performance, making it suitable for use with many beverages. Tests also concluded that seals made of perfluoroelastomer (FFKM), such as the Trelleborg Sealing Solutions Isolast FoodPro compounds, can be an effective solution. The FFKM materials did not absorb aromas and showed virtually no detectable effect on the taste of subsequent beverages, even under unfavourable conditions. This makes these sealing materials ideal for use on bottling lines processing beverages with intense flavours, the company concludes.