During the summer, researchers from the University of Reading grew five cultivars of Eruca sativa as well as a commercial varieity of Diplotaxis tenuifolia. Upon harvesting, the produce was processed like that destined to the fresh-cut chain.
"Our objective was to understand what are the effects on the phytochemical composition of the leaves during the various processing stages, from harvesting management, to processing in the fresh-cut facility, to distribution. We analysed glucosinolate, isothiocyanate, amino acid, free sugar and bacterial load levels throughout the chain."
Bacterial load increased significantly over time and peaked during shelf life storage. In addition, correlations were observed with glucosinolate and amino acid concentrations, suggesting a previously unknown relationship between plants and endemic leaf bacteria.
Glucosinolates, isothiocyanates and amino acids increased significantly after processing and during shelf-life . The supply chain did not significantly affect glucoraphanin concentrations, while sulforaphane significantly increased after processing, especially in E. sativa cultivars.
"These are just some of the results we obtained, which led us to hypothesise that commercial processing may increase the nutritional value of the crop, with added benefits for the consumer."
Source: Luke Bell, Hanis Nadia Yahya, Omobolanle Oluwadamilola Oloyede, Lisa Methven, Carol Wagstaff, 'Changes in rocket salad phytochemicals within the commercial supply chain: Glucosinolates, isothiocyanates, amino acids and bacterial load increase significantly after processing', 2017, Food Chemistry, Vol. 221, pag. 521–534.
www.sciencedirect.com/science/article/pii/S0308814616320039