SO2, high pressure processing and pulsed electric field treatments of red wine: Effect on sensory, Brettanomyces inactivation and other quality parameters during one year storage

Abstract

Abstract The use of sulphur dioxide (SO2), high pressure processing (HPP) and pulsed electric fields (PEF) for wine preservation was compared. The difference between HPP and PEF wines and untreated wine after one year's storage, in terms of sensory quality, B. bruxellensis inactivation, colour density, total phenolic content and volatile phenol concentration, was determined. SO2 and HPP led to >5 log inactivation of B. bruxellensis, however SO2 treated cells were able to recover after 10 months storage. PEF treatment provided insufficient inactivation (0.8 log reduction). HPP was the only treatment which prevented Brettanomyces growth and the formation of off-flavours and –odours after storage. SO2 and PEF treatments had no significant effect on wine quality, while the colour and phenolic quality of HPP treated wine deteriorated after six months. HPP and PEF also had no effect on the overall sensory quality of the wines. Overall, HPP was able to produce a microbiologically stable wine, with no effect on the taste of the wine. Industrial relevance Brettanomyces is a spoilage concern in the wine industry, conventionally controlled using SO2. Due to its adverse effects on some consumers, the use of emerging non-thermal technologies has started to garner great interest in the food and beverage industry. The results show that HPP is a non-thermal treatment with the potential to reduce the use of SO2 for the preservation of wine in the industry. However, to extend the quality of HPP treated wine beyond six months storage and retain wine colour and total phenolic content, small doses of SO2 may be required. Since, PEF is a continuous process, integration of this technology into current wine production practices would be less challenging than for HPP. This study also underscores the importance on conducting regular tests for B. bruxellensis contamination in the wine industry, because even when plate counts are negligible this yeast has the ability to recover when conditions become favourable again.