RELATION BETWEEN ENDOGENOUS ETHYL-ALCOHOL AND BROWNING IN SHIITAKE (LENTINUS-EDODES SING) MUSHROOM DURING STORAGE IN POLYETHYLENE FILM BAGS

Browning of shiitake was inhibited by packaging with polyethylene film bags (PE). In order to clarify the inhibitory effect on browning of s hiitake, we investigated the relation between gas composition and brow ning of shiitake with PE packaging or by treating with ethyl alcohol ( EtOH) vapor in desiccator. Concentration of EtOH in tissues of shiitak e packaged with PE increased during storage (15 mM, 6 days storage at 20-degrees-C), and there was a negative correlation (r = -0.75*) betw een EtOH concentration and browning-index. Treatment of air + EtOH inh ibited the increase in both browning-index and polyphenoloxidase activ ity. The inhibition of browning in the treatment Of CO2 10% + O2 1% EtOH was more effective than in air + EtOH. On the other hand, the inh ibition of polyphenoloxidase activity was identical with both of two t reatments. From these results, we suggested that the inhibition of bro wning in shiitake packaged with PE was not directly caused by high CO2 and low O2, but resulted from endogenous EtOH accumulation in shiitak e under the conditions of high CO2 and low O2.