Invisible light, visible results: gamma irradiation effects on aromatic, edible and medicinal plants

Aromatic, edible and medicinal plants require effective conservation technologies to expand their use. During the processing and storage, they can be easily exposed to contamination that can lead to a microbial deterioration or insect infestation compromising its quality and shelf life. In this study, one of the most promising decontamination methods for many foodstuffs and plant materials was applied. The effects of gamma irradiation in chemical (aromatic plant- Aloysia citrodora Palàu), nutritional (edible plant- Nasturtium officinale W.T. Aiton) and anti-hepatocellular carcinoma (medicinal plant- Cochlospermum angolensis Welw.) properties were evaluated for doses up to 10 kGy. The results showed that each plant was differentially affected by irradiation treatment. For aromatic and edible plants, the effects of gamma irradiation in chemical and nutritional properties proved to have statistical significance in some particular cases. However, when analyzed under an integrated approach, non-irradiated and irradiated samples were grouped indiscriminately, indicating that irradiation treatment did not cause sufficient changes to define a specific chemical profile. Regarding the medicinal plant, irradiated samples kept the anti-hepatocellular carcinoma activity, but a decrease was observed in the methanolic extract prepared from the sample irradiated at 10 kGy. Overall, it might be considered that gamma irradiation, up to 10 kGy, is a feasible conservation technology for the assayed plant species and that irradiation might ensure plant decontamination, while maintaining their chemical, nutritional and bioactive qualities.AROMAP (Project PRODER - Ministry of Agriculture) for financial support and E. Pereira grant. Foundation for Science and Technology (FCT, Portugal) for financial support to CIMO (PEst-OE/AGR/UI0690/2014), C2TN (RECI/AAG-TEC/0400/2012) and J. Pinela (SFRH/BD/92994/2013). The authors also thank to “MaisErvas - Aromáticas e Medicinais” and “Américo Duarte Paixão Lda” companies (Portugal), for providing the samples