Improving fresh-cut watercress shelf-life: a study on the suitability of modified atmospheres and conventional packaging

Watercress (Nasturtium officinale R. Br.) is a nutrient rich perennial plant of the Brassicaceae family highly appreciated in the Mediterranean cuisine. It is eaten raw in salads, soups and other recipes and used in folk medicine due to its medicinal and therapeutic properties (1-3). Due to its reduced shelflife, the effects induced by different packaging systems on physical, chemical and functional quality parameters were evaluated and compared in order to select the most efficient treatment for shelf-life extension. Wild samples were gathered in Bragança region (Northeast of Portugal), rinsed in tap water and a portion was immediately analyzed (control). The remaining fresh material was packed in conventional (air- and vacuum-packaging) and non-conventional (N2- and Ar-enriched modified atmospheres (MAP)) systems, and stored at 4 ºC for 7 days. After assessing the effect on individual parameters, a Linear Discriminant Analysis provided an overview about the suitability of the tested packaging system in maintaining the fresh-like properties of the control samples throughout the storage time. The complete individualization of the four packaging systems was observed, being the air-packaged samples those to present the most dissimilar profiles from the control, followed by the N2-enriched MAP ones. In turn, Ar-enriched MAP was the best option to preserve the overall quality. Nevertheless, some of the observed changes were advantageous for the samples’ functional properties. Thus, this study highlighted Ar-enriched MAP as the best option to preserve fresh-cut watercress during refrigerated storage. Further studies are necessary to evaluate the effects on physiological and sensorial parameters