Impact of high pressure treatments on the physicochemical properties of a sulphur dioxide-free white wine during bottle storage: Evidence for Maillard reaction acceleration Mickael C. Santos a , Cláudia Nunes a, ⁎, M. Angélica M. Rocha a , Ana Rodrigues b , Sílvia M. Rocha a , Jorge A. Saraiva a , Manuel A. Coimbra a a QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal b Dão Sul — Sociedade Vitivinícola, S.A., 3430-909 Carregal do Sal, Portugal abstract article info Article history: Received 5 May 2013 Accepted 7 July 2013 Editor Proof Receive Date 5 August 2013 Keywords: Color Antioxidant activity Maillard reaction Sensorial analyses High pressure Amino acids The impact of high hydrostatic pressure (HHP) treatments on physicochemical characteristics of sulphur dioxide-free white wines was studied during one year of bottle storage. For this purpose, a white wine was produced without the addition of sulphur dioxide (SO 2 ) and was pressurized at two pressure conditions, 500 and 425 MPa, for 5 min at 20 °C. A wine with 40 ppm of SO 2 and a wine with no preservation treatment were used as controls. Pressurized wines showed, after one year of storage, a more brownish color (higher a* and b* values and lower L*) and a slightly lower antioxidant activity and total content of phenolic compounds compared to the unpressurized wines (wine with SO 2 and wine without any treatment). These results, to- gether with the lower content of free amino acids (e.g. 87% less of serine) and higher content of furans (e.g. 10 fold higher of 2-furfural), presented in the pressurized wines after nine months of storage, lead to propose an effect of HHP treatments in the acceleration of Maillard reactions occurring during the wine stor- age period. Industrial relevance: HHP might be used in winemaking as an alternative process for preservation of wine, which can lead to the production of a wine with reduced amounts of SO 2 . Until now, the physicochemical and sensorial properties of wine have been studied only after the pressure treatment, without ever having references on the influence of the treatment in wine properties during storage. Then, the effect of HHP on the physical–chemical characteristics on long term storage of wine is still largely unknown. This work shows that HHP treatments accelerate Maillard reactions during the white wine storage period. This reaction should be taken into consideration in the implementation of HHP treatments to wine conservation as alter- native to SO 2 . © 2013 Elsevier Ltd. All rights reserved. 1. Introduction Consumers demand high quality processed food with a natural flavor, taste, and appearance. Besides, they look for safe and natural products, if possible, without additives (Rastogi, Raghavarao, Balasubramaniam, Niranjan, & Knorr, 2007). In oenology, one major concern is the use of sulphur dioxide (SO 2 ) during the technological process. Despite that SO 2 is a versatile and efficient additive due to its antiseptic and antioxi- dant properties, this compound has been related to intolerance or even allergic reactions in some consumers (Vally, Misso, & Madan, 2009). Due to the health related problems that have been associated with SO 2 use, the International Organization of Vine and Wine (OIV) has pro- gressively reduced the maximum concentration authorized in wines (Garcia-Ruiz et al., 2008), which is 200 mg/L for white wines (Regulation (EC) 607/2009). For this reason, it is crucial in a competitive global winemaking market strategy, search for new healthier and safe strate- gies, in order to reduce or even eliminate the use of SO 2 as preservative. One emerging technology receiving a great deal of attention is high hydrostatic pressure (HHP), not only because of its food preservation ca- pability, but also because of its potential to achieve relevant functional ef- fects (Ramirez, Saraiva, Lamela, & Torres, 2009; Santos, Nunes, Saraiva, & Coimbra, 2012). The use of HHP treatments has already been reported as an alternative process to preserve wine (Buzrul, 2012; Mok et al., 2006; Morata et al., 2012). Pressures between 300 and 500 MPa for 5–15 min showed the inactivation of fungi, yeasts, and lactic and acetic acid bacte- ria in white wines with no significant changes on sensorial characteris- tics (Mok et al., 2006; Puig, Vilavella, Daoudi, Guamis, & Mínguez, 2003). However, Tao et al. (2012) showed that severe high pressure treatments (650 MPa for 1 and 2 h) changed the physicochemical char- acteristic of red wine, namely the decrease of color intensity and content of phenolic compounds. In terms of sensorial properties, the sour and Innovative Food Science and Emerging Technologies 20 (2013) 51–58 ⁎ Corresponding author. Tel.: +351 234 372581; fax: +351 234 370084. E-mail address: claudianunes@ua.pt (C. Nunes). 1466-8564/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ifset.2013.07.001 Contents lists available at ScienceDirect Innovative Food Science and Emerging Technologies journal homepage: www.elsevier.com/locate/ifset