Effects of Pre-treatments and Drying Methods on Cyanide and Functional Properties of Cassava (Manihot esculenta Crantz) Flour

The main purpose of this research was to determine the effect of different pre-treatments and drying methods on the cyanide content and functional properties of cassava flour in Yola, Adamawa State. Cassava has been considered the 4th most important food security crop, but there is a high content of cyanide, which renders the crop unsafe for human consumption. The cassava tubers (Manihot esculenta Crantz) were obtained during the 2022 and 2023 seasons at the sub-station of National Root Crops Research Institute (NRCRI), Nyanya, Abuja and the variety used was “TME-419”. The harvested tubers were subjected to different pre-treatments (48 hrs soaking in water, 2 and 4 minutes blanching) prior to three different drying methods (shade, sun, and oven). The time taken for the drying were 750C for 74 hours, 27.420C for 8 days, and 25.650C for 10 days for oven, sun, and shade drying, respectively, before milling into flour and the flour samples were analyzed for their cyanide content and functional properties. There was no significant difference (P>0.05) observed among the pre-treatments and drying methods on cyanide content in 2022 but there was a significant difference (P≤0.05) in 2023. In 2023, the highest of 0.092 mg/100g was obtained from 2 minutes of blanching followed by 4 minutes blanching with 0.081 mg/100g, while the least of 0.077 mg/100g was found from 48 hrs soaking in water. On the other hand, the highest cyanide of 0.081 mg/100g was equally obtained from sun and oven drying while the least of 0.079 mg/100g was obtained from shade drying. All the pretreatments and drying methods used in this experiment were capable of lowering the cyanide content within the acceptable limit. However, oven drying was found to be faster than sun and shade drying methods, but sun and shade drying were cheaper and accessible than oven. Therefore, any of the pretreatments used in this research should be adopted before drying in order to reduce the cyanide content, improve functional properties and also extend the shelf life of cassava flour.