Study On New Postharvest Techniques Of Sweet Potatoes

Sweet potato is nutrient-riched and has high production level, which is an important grain, fodder and energy crops. Sweet potato can only be storaged at high temperature condition. When the storage temperature is below 10 °C, it will lead to serious chilling injury. The quality of sweet potato depresses significantly during storage, which usually leads to serious storage losses for the industy. So far, the sweet potato large-scale storage is still unsuccessful in China. In this paper, we studied on varieties, curing, sprouting, and decay problems, which influence the quality of postharvest sweet potato. The main results are as follows:(1)The sensory quality, decay rate and weight loss rate were counted to evaluate the sweet potato storability. Sushu#8 and Hong Xiangjiao had lower decay rate during storage period, which were suitable for long-term storage. The decay rate and weight loss rate of Beijing#553 and Yuzi#7 were more serious than the other two varieties, which would lead to huge commercial damage during storage. The antioxidant ability of Yuzi#7 was the highest in the four varieties, which was rich in total phenols, flavonoid, and anthocyanin.(2)29 °C?4 d is the best curing condition. Compared with control, curing treatment could significantly reduce the decay rate of sweet potato, improve reducing sugar and soluble sugar contents, and reduce starch contents. DPPH radical scavenging capacity of curing treatment was higher than controlIodine staining is a new technique of sweet potato curing degree examine, which is first invented in this research. The result of iodine staining was consistent with phloroglucinol staining method. This method was more intuitive, simple and convenient to operate compared with other methods.(3)Sweet potato is easy to sprout during curing process, as a result, it is necessary to study appropriate control techniques. Ethylene, 1-MCP, CIPC and ABA treatments could effectively inhibit germination of sweet potato. However, CIPC and ABA suppressed curing process. Moreover, ethylene, CIPC and ABA treatments increased the decay of sweet potato. As a result, 1-MCP treatment was the best technique to inhibit germination during curing processs.(4)As long as 7 months' storage, 29 °C curing+1-MCP, fludioxonil powders, fludioxonil powder+58 °C hot air, 600 ?g/L fludioxonil could control rot of sweet potato, and the decay rate was below l0%. As long as 9 months' storage, 29 °C curing+1-MCP was the best treatment. To sum up, curing treatment combined with 1-MCP or fludioxonil was better method of sweet potato rot prevention.