Abstract:

In order to understand the key invertase of sucrose degradation in stalk of sweet sorghum during storage. The changes of the content of sucrose, fructose and glucose and the activity of soluble acid invertase, neutral invertase and sucrose synthase from sweet sorghum stalk of Liaotian No.1, No.4 and No.6 were measured, using HPLC and enzyme assay method for after 75 days post-harvest storage. The results showed that the sugar decomposed rapidly during storage, then the total sugar lost nearly half, 68.2-31.9(g/100gdry basis), 43.0-18.1 (g /100gdry basis) and 59.6-25.3 (g/100g dry basis) respectively. The trend of sucrose, fructose and glucose for these three species of sweet sorghum displayed a general downward, and the sugar reduced quickly after the beginning of storage period, then slowly decreased. The activity of soluble acid invertase had a significant increase at the first 15 days stem-storage, and increased in minor amplitude, while the enzyme kept a high activity during storage. The activity of neutral invertase kept increasing at small amplitude, but the enzyme activity stayed at a low level without significant changes. The activity of sucrose synthase of the decomposition direction was even lower, and with little change. This indicated that the acid invertase might be closely related to the sucrose degradation in sweet sorghum stalks during storage.