Comparison study about processing methods (postharvest treatments) and their effects on the nutritional quality of different Brassica vegetables

An increasing number of medical studies is focusing the attention on the benefits of a higher intake of Brassica vegetables and the decrease of the onset of several human chronic pathologies. This health-promoting activity of Brassicaceae is mainly due to the presence of bioactive compounds characteristic of this genus. The aim of this study was to investigate the differences in the composition of different Brassica species, fresh or subjected to two processing methods applied during the post-harvest period; in particular, the variation of bioactive compounds in raw, freeze-dried, and air-dried samples were analyzed. The total antioxidant capacity, the total anthocyanin content, and the total phenolics contents were analyzed. The nutritional quality is also investigated with the measurement of ascorbic acid content in the fresh material, through the determination by HPLC analysis. The results confirm the high nutritional quality of the species belonging to the Brassicaceae family and the presence of a high amount of bioactive compounds, in particular, among the different treatments, the fresh samples showed the highest values both for TPH and TAC, followed by lyophilized samples, which retain those compounds better than dried samples.