Effect of Drying Methods on Physicochemical Properties and Residual Cyanide Content of Cassava Flour from Rayong 11 Variety

Abstract

     This research investigated the effects of five different drying methods (namely sun drying for 3 days, solar drying for 3 and 7 days, and hot air oven drying for 3 and 12 hrs) on the residual cyanide content and physicochemical properties of cassava flour from the Rayong 11 variety. The results show that sun drying was a highly effective method, with a cyanide reduction rate of 96.75%. This effectiveness is attributed to the prolonged enzymatic reaction time, allowing the linamarase enzyme to facilitate the hydrolysis of cyanogenic glycoside into cyanohydrin and free cyanide, compared to other drying methods. However, the color parameter, specifically the lightness (L*), of the five samples of cassava flour dried using different methods ranged from 93.80±0.05 to 97.17±0.12. The lightness (L*) decreased, while redness (a*) and yellowness (b*) significantly increased with a statistical significance level (p ≤ 0.05) as the drying duration increased. Cassava flour dried in the solar dryer for 3 days exhibited the highest peak viscosity (219±1.4 RVU), while cassava flour dried in the solar dryer for 7 days exhibited the highest water absorption (2.12±0.04 g/g dry weight). The cassava flour produced by all five methods had moisture content within the standard limit for cassava products, not exceeding 14.0% by dry weight and the water activity was lower than 0.6. The data from the studies indicates that it is possible to produce low-cyanide cassava flour from bitter cassava by sun drying or solar drying, which can be used as a database for future studies.