Hiroshimana (Brassica pekinensis var. Hirosimana), a Brassicaceae vegetables, is commonly salted for its consumption in the picked form. Isothiocyanate (ITC), volatile and pungent compound, is a major component of pickled Hiroshimana. The enzymatic actions of myrosinase causes cleavage of thio-linked glucose, releasing ITC as byproduct.
ITC is very reactive and unstable compound; this instability limits its application in food processing.
The formation and decomposition of ITC in Hiroshimana during salting was investigated. The results showed that myrosinase activity was suppressed as NaCl concentration increased. Moreover, ITC formation was inhibited by lowering the temperature and increasing the NaCl concentration, leading to a lower ITC formation rate during salting.
However, the ITC decomposition rate is drastically reduced at low temperature. Therefore, it is quite difficult to preserve the flavor of Hiroshimana in the absence of low temperature during salting, storage and transportation.