Quality Changes of Two Breeds of Sweet Potato at Mid and Late Preservation Stage

This study evaluated the quality changes of yellow sweet potato and white sweet potato stored for 60～165 days under the conditions of room temperature(7～22 ℃) and relative humidity 80%～88%.The results were as follows: During storage at room temperature,the rot rate and weight loss rate of sweet potato increased gradually;moisture content,soluble protein content,soluble total sugar content and total starch content generally showed a downward trend;L*,a* and b* values were more stable,and the activities of α-amylase,β-amylase and total amylase were in fluctuating state.In general,for two breeds of sweet potato,there was a rapid increaser rot during 120～135 days' storage,accelerated deterioration of nutrition after 120～135 days' storage,and a peak stage of amylase activity after 105 days' storage.In addition,the storage quality of white sweet potato was obviously better than that of yellow sweet potato stored at room temperature as a whole.