Effects of gamma-irradiation on the flavour of dry shiitake (Lentinus edodes Sing)

Dry shiitake (Lentinus edodes Sing) was irradiated with doses of 5 and 10 kGy using 60Co. The total volatile compounds were decreased by more than 50%. Irradiation increased the concentrations of some minor volatile compounds, such as 3-methyl-2-butanol and 1-hexanol. However, the major flavour compounds including eight-carbon and sulphur-containing compounds were significantly reduced. The ratio of the eight-carbon compounds, such as 3-octanone, 3-octanol and 1-octen-3-ol, to total volatiles decreased from 72% in the control to 21% in the 10 kGy irradiated samples. The unidentified compounds which may have been formed by decomposition or polymerization following irradiation of precursors need to be studied in greater depth.