Effect of ultrasonic pretreatment on eliminating cyanogenic glycosides and hydrogen cyanide in cassava.

Traditional soaking method takes days to remove cassava cyanide. Ten minutes of ultrasonic pretreatment (UPT) was found to be a new effective method to eliminate both cyanogenic glycosides and hydrogen cyanide in cassava. Here, the parameters of UPT were optimized and the underlying mechanisms were investigated. 40.36% and 24.95% of hydrogen cyanide and cyanogenic glycosides in cassava juice were eliminated under 10 min of UPT (45℃, 81 W). UPT before boiling enhanced the total cyanide elimination to 41.94%. The degradation patterns of hydrogen cyanide and cyanogenic glycosides were different. Ultrasound directly eliminated hydrogen cyanide and indirectly degraded cyanogenic glycosides through promoting enzymatic hydrolysis. The ß-glucosidase activity was increased by 17.99% induced by ultrasound. This was supported by the movement of hydrophobic residual and the rearrangement of the secondary structure of the molecular as found in fluorescence, CD, FTIR, DSC and TG analysis. This study revealed that UPT acted as a fast and simple technical way in improving cassava safety.