Postharvest Biology and Technology 73 (2012) 50–55 Contents lists available at SciVerse ScienceDirect Postharvest Biology and Technology journa l h o me pa g e: www.elsevier.com/locate/postharvbio Effect of noble gas-enriched atmospheres on the overall quality of ready-to-eat arugula salads Cielo Char a,c,1,2 , Ana Cecilia Silveira b , Carlos Inestroza-Lizardo a,1 , Andrea Hinojosa a,1 , Alejandra Machuca a,d,1 , Víctor Hugo Escalona a,d,∗ a Center of Postharvest Studies, University of Chile, Santa Rosa 11315, La Pintana, P.O. Box 1004, Santiago, Chile 3 b Postharvest Fruit and Vegetable Crop Production Department, Faculty of Agriculture, University of the Republic, Avenida Garzon 780, CP 12300, Montevideo, Uruguay c Agroindustry and Enology Department, Fac. Agricultural Sciences, University of Chile, Santa Rosa 11315, La Pintana, P.O. Box 1004, Santiago, Chile d Agricultural Production Department, Fac. Agricultural Sciences, University of Chile, Santa Rosa 11315, La Pintana, Santiago, Chile a r t i c l e i n f o Article history: Received 4 April 2012 Accepted 24 May 2012 Keywords: Eruca vesicaria Argon Helium Modified atmosphere packaging Hydrogen peroxide Antioxidant activity a b s t r a c t The shelf-life of ready-to-eat arugula salads is principally limited by increased metabolic activity, color degradation and microbial growth. The effect of modified atmosphere packaging (MAP) enriched with non-conventional gases (Ar, He, and N 2 ) combined with two sanitization treatments (NaClO or H 2 O 2 ) was assessed. The respiration rate, ethylene emission, microbial growth, color, and functional compounds of ready-to-eat arugula were determined. After sanitization with NaClO (100 mg L −1 , pH 6.0) or H 2 O 2 (30 mg L −1 ), the leaves were packed in three different atmospheres enriched with Ar (65–70% Ar + 5–6% O 2 balanced with N 2 ), He (70–75% He + 5–6% O 2 balanced with N 2 ) or N 2 (94–95% N 2 + 5–6% O 2 ) and stored at 5 ◦ C for 8 days. The samples in the Ar-enriched atmospheres exhibited respiration rates 13–17% higher than the leaves under He and N 2 enrichment. The sanitation method also affected the respiration rate because the H 2 O 2 treatments resulted in increased CO 2 and C 2 H 4 production compared to NaClO. Our results suggest that noble gas-enriched atmospheres are efficient tools for maintaining the overall quality of arugula salads. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Arugula (Eruca vesicaria Mill.), belonging to the Brassicaceae family, originates from the Mediterranean region but is distributed worldwide. The leaves and young stems are eaten in salads and are specially appreciated due to their unique, slightly spicy flavor. Bras- sicaceae vegetables contain many biologically active molecules; in particular, they are a good source of biologically active sulfur and nitrogen compounds, which are associated with several health benefits, making arugula even more attractive to consumers who are increasingly more concerned about healthy eating (Martínez- Sánchez et al., 2006a,b; Manchali et al., 2012). Arugula usually has a shelf-life period of 8–12 days when stored under optimum conditions (0 ◦ C and 100% RH). However, these con- ditions are difficult to maintain, especially during transportation ∗ Corresponding author at: Center of Postharvest Studies, University of Chile, Santa Rosa 11315, La Pintana, P.O. Box 1004, Santiago, Chile. Tel.: +56 2 9785841/9785823; fax: +56 2 9785813. E-mail address: vescalona@uchile.cl (V.H. Escalona). 1 Tel.: +56 2 9785841/9785823; fax: +56 2 9785813. 2 Tel.: +56 2 9785731; fax: +56 2 9785796. 3 www.cepoc.cl. when the temperature rises and the relative humidity is variable (Nielsen et al., 2008; Koukounaras et al., 2009). Modified atmosphere packaging (MAP) is widely used for fresh products to maximize the shelf-life and is based on an increase in CO 2 and decrease in O 2 concentrations, thus reducing the metabolic activity (Sandhya, 2010). Modified atmospheres (low O 2 and high CO 2 , balanced by N 2 ) used for arugula leaves can be beneficial in quality preservation. However, this effect can be modified where characteristics of film permeability induce non-beneficial results (Martínez-Sánchez et al., 2006a,b). The use of an active modified atmosphere, including such noble gases as argon (Ar), helium (He) or xenon (Xe), or other non-conventional atmospheres, such as nitrous oxide (N 2 O), superatmospheric oxygen or nitrogen (N 2 ), has also gained interest in recent years (Escalona et al., 2005; Rocculi et al., 2005; Artés et al., 2009). The noble gases are a group of elements characterized by their lack of, or low, reactivity. Helium-enriched MAP (83% He + 15% CO 2 + 2% O 2 and 98% He + 2% O 2 ) has reduced the mesophilic bac- teria count on mizuna leaves by more than 1 log unit and kept microbial growth under the limit defined as safe for consumption by Spanish legislation over 8 days at 5 ◦ C (Robles et al., 2010). Argon has been reported to be biochemically active, probably due to its enhanced solubility in water compared to nitrogen, and the gas appears to interfere with enzymatic oxygen receptor sites, thus 0925-5214/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.postharvbio.2012.05.010