Cyanogenic compounds removal and characteristics of non- and pregelatinized traditional detoxified wild yam (Dioscorea hispida) tuber flour

Abstract

The presence of cyanide compounds restricts the utilization of wild yam (Dioscorea hispida) tubers for food or food ingredients. Traditional detoxification, usually used in wild yam chips processing, has not been evaluated for its effectiveness in reducing cyanogenic compounds. Processing into flour will increase wild yam tubers utilization and pregelatinization usually improve flour functional properties. This study aimed to evaluate the effect of 4 traditional detoxification methods and pregelatinization on cyanogenic compounds removal and wild yam tuber flour characteristics. The different methods were in rubbing ash, soaking time, and pregelatinization methods by boiling or steaming. The duration of a particular step was also different. The results showed that traditional detoxification methods reduced total cyanides 97%, cyanogenic glycosides 98-100%, acetone cyanohydrin 89-97%, and HCN 94-95%; also affected degree of cyanogenic compounds removal. Pregelatinization also reinforced the degree of cyanogen removal. Tuber flour physicochemical properties were affected by detoxification methods and pregelatinization. Modification of starch might occur due to the presence of SiO2 and calcium in rubbing ash and affected functional properties of wild yam tuber flour. Starch granule morphology appeared not to be affected by detoxification methods. Traditional detoxification methods could be used to make a safe wild yam tuber flour.