1972 Volume 19 Issue 11 Pages 508-513
The purpose of this experiment was to determine the changes of o-diphenol, ascorbic acid and activities of polyphenol oxidase and peroxidase, accompanied with the browning by the low dose of gamma ray, in three parts of tuber tissue (cortex, vascular bundle and pith), and to observe the relation between the browning and the changes of those compounds and enzyme activities.
1. The o-diphenol content increased in irradiated tubers and the increasing rate was greater in cortex and vascular bundle than in pith. The ascorbic acid content decreased with higher doses, and the decreasing rate was greater in cortex and vascular bundle than in pith.
2. The activities of polyphenol oxidase and peroxidase also increased in irradiated tubers. The activity of polyphenol oxidase increased more in cortex than in vascular bundle and pith and the activity of peroxidase increased more in vascular bundle than in cortex and pith.
3. In the potato tubers which irradiation was conducted immediately after harvest, the browing was induced within several days after irradiation. However, in the potato tubers which irradiation was conducted about 3 months, the browning did not occur after irradiation. The former showed the increase of o-diphenol content and the activities of these enzymes and the decrease of ascorbic acid content, the latter did not show the changes of o-diphenol and ascorbic acid and activities of the enzymes.
