Effect of a High Temperature-Curing Treatment on Storability in Sweet Potato (Ipomoea batatas L.) 'Kokei No.14' Naruto-Kintoki

Abstract

　To evaluate the transportation environment from Tokushima, Japan to Kelang, Malaysia by overland and marine shipping, we measured the chronological fluctuation in temperature and humidity in the reefer container and the carton of sweet potatoes. Further, we clarified the effects of the curing treatment and the high-temperature curing treatment before shipping on root quality during storage in Naruto-Kintoki selected from sweet potato 'Kokei No.14'. By combining the reefer container and the warehouse (which have temperature control), the optimum temperature (13℃) of sweet potato was maintained during the distribution process. However, humidity during marine transportation had a wider fluctuation. After 52d of storage, the high temperature-curing treatment (42℃ for 36h) significantly decreased the weight-change ratio and the mold incidence ratio on the cutting surface of the root. After 23d of storage, the rot ratio and the disposal ratio for serious mold/rot on the root were significantly decreased. The effects of the curing treatment (35℃ for 72h) on quality retention (weight-change ratio, wilting ratio, and mold incidence ratio on the cutting surface of root) were not apparent. The rot ratio and the disposal ratio decreased during the storage period (not significantly, though). The high temperature-curing treatment improved preservation as evidenced by the decrease in the disposal ratio of Naruto-Kintoki. After 52d of storage, the disposal ratio was 4.9% in the control and 0.7% in the high-temperature curing treatment.