Suitability of gamma irradiation for preserving fresh-cut watercress quality during cold storage

The suitability of gamma irradiation (1, 2 and 5kGy) for preserving quality parameters of fresh-cut watercress (Nasturtium officinale R. Br.) during storage at 4±1°C for 7d was investigated. The storage time decreased the protein content and the main carbohydrates, and increased the levels of malic and fumaric acids, sucrose and mono- and polyunsaturated fatty acids (MUFA and PUFA). The different irradiation doses did not caused any significant colour change. In general, the 2kGy dose favoured PUFA and was the most suitable to preserve the overall postharvest quality of fresh-cut watercress during cold storage. In turn, the 5kGy dose better preserved the antioxidant activity and total flavonoids and favoured MUFA, tocopherols and total phenolics, thus originating a final product with enhanced functional properties. Therefore, the suitability of gamma irradiation for preserving fresh-cut watercress quality during cold storage was demonstrated.

The authors are grateful to PRODER research project nº 53514, AROMAP, for financial support of the work; to the Foundation for Science and Technology (FCT, Portugal) for financial support to CIMO (PEst-OE/AGR/UI0690/2014), C2TN (RECI/AAG-TEC/0400/2012), J. Pinela (SFRH/BD/92994/2013), J.C.M. Barreira (SFRH/BPD/72802/2010) and L. Barros (SFRH/BPD/107855/2015); and to FCT/MEC for financial support to REQUIMTE/LAQV (UID/QUI/50006/2013 - POCI/01/0145/FEDER/007265) through national funds and co-financed by FEDER, under the Partnership Agreement PT2020.