Effects of argon gas in minimally processed lettuce shelf life

Fresh - cut lettuce is normally packaged in low ? oxygen atmosphere to prevent browning and quality loss. Objective of this work was to test the effect of non ? conventional atmospheres enriched with argon on microbial growth, enzyme activity, and sensory and nutritional quality of fresh - cut lettuce. ?Iceberg? lettuce was processed according to industry procedures and stored in a humidified flow of air (control) and of the following atmosphere: 97% Ar + 3% O2, 50% Ar + 3% O2, (in nitrogen), 3% O2 (in nitrogen). Samples (three replicates) were stored at 5? C and evaluated initially and after 2 and 9 days of storage. All atmospheres were ?effective in slowing down respiration rate at 9 days compared to control, whereas no significant difference were observed for color, texture, flavor, phenols, antioxidant activity, acetaldehyde, ethanol and soluble solids content. Samples stored in 50% Ar + 3% O2 and in 3% O2 in nitrogen showed lower PPO activity than control, whereas samples stored in 97% Ar - enriched atmosphere exhibited an intermediate value. Samples stored in 50% Ar - enriched atmospheres and samples stored in air showed higher cut edge discoloration compared to samples stored in the other treatment conditions, whereas sample stored in 3% O2 + 97% Ar showed an intermediate value. Moreover lettuce stored in the latter conditions best retained ascorbic acid up to 2 days of storage, but no differences among treatments were detected after 9 days. At the end of the experiment samples in 3% O2 in Nitrogen showed the lowest mesophilic load, whereas both 3% O2 in Argon and 3% O2 in Nitrogen resulted effective to slow down yeast and mould growth. Our results suggest that performance of argon ? enriched atmosphere is quite similar to conventional modified atmospheres, with a lower control of mesophilic bacteria and a better retention of vitamin C. Further investigations are needed to confirm these results in order to eventually propose argon as an alternative gas in modified atmosphere packaging of fresh - cut lettuce. ? Original tittle, complete list of authors, and sourceSHELF - LIFE OF FRESH - CUT ?ICEBERG? LETTUCE Baldassarre, V.(*), Amodio, M.L. and Colelli, G.g.colelli@unifg.itDip.to di Scienze Agrarie, degli Alimenti e dell?Ambiente - Universit? di Foggia, Via Napoli 25, 71122 Foggia, Italy CA MA 2013, XI International Controlled & Modified Atmosphere Research Conference, Trani (Italy), 3-7 June 2013Pictures by the authors. ? ?