Effect of soaking and heating stimulation on the formation of isothiocyanates in Eruca sativa Mill. seeds and sprouts

Abstract

The present work investigated the effects of soaking followed by heating on the metabolism of glucosinolates (GLs) in rocket seeds and sprouts. Soaking for 1 h increased myrosinases (MYR) activity of seeds. Heating at 70°C for 10 min after soaking resulted in the highest isothiocyanates (ITCs) formation in seeds. Both immerse-heating and steam-heating decreased the total GLs content in seeds and 2-day old sprouts. However, steam-heating showed minor effect on total GLs content when compared with immerse-heating. Both methods showed a decreased MYR activity in seeds and sprouts. Nevertheless, heating had a positive impact on ITCs formation. Under immerse-heating, ITCs formation was the highest in seeds and sprouts at 70°C heating. However, under steam-heating, ITCs formation in seeds and sprouts was higher at 70 and 60°C, respectively. The results indicated that steam-heating treatment was effective for improving ITCs formation in rocket seeds and 2-day old sprouts.