Fortification of an Innovative Tomato Cold Soup with High Bioaccessible Sulforaphene from UV-B–Treated Radish Seeds

Abstract

The aim of this work was to develop an innovative tomato cold soup fortified in bioactive compounds through the incorporation of UV-B–treated radish seeds. After a 20 kJ m−2 UV-B treatment, radish seeds increased their sulforaphene content by 30%. Different concentrations of UV-B–treated seeds (0, 0.5, 1.5, 3, and 5 g kg−1) were added to a chopped vegetables cold soup, mainly made of Kumato® cherry tomatoes as novelty, including pepper, cucumber, and garlic, which was stored for 8 days at 4 °C. Added seeds did not affect physicochemical quality attributes, microbial growth, nor sensory perception. Nevertheless, a dose-dependent behaviour was shown in glucoraphenin and sulforaphene content, according to concentrations of UV-B–treated seeds added. It was also appreciated after an in vitro digestion that the bioaccessible fraction of glucosinolates and isothiocyanates was kept constant throughout the refrigerated storage. The sulforaphene content of the soup increased by ~ 19% after 2 days at 4 °C, of which the 33% was bioaccessible (measured in vitro), and subsequently was degraded by ~ 20% after 8 days at 4 °C.