EFFECTS OF pH AND PROCESSING ON THE CYANOGEN POTENTIALS OF IRISH POTATO (Solanum tuberosum) USING CYANOMETHAEMOGLOBIN COMPLEX

This study was aimed at determining the cyanogen potentials of raw, cooked, parboiled, roasted and baked Irish potatoes (Solanum tuberosum). Effect of pH on the cyanogen potentials of the processed Irish potato was carried out. The examination was carried out at pHs values ranging from 5.6 to 9.0, at intervals of 0.2 using a colorimeter through the formation of cyanomethemoglobin. There was variation in the cyanide concentration with respect to the pHs difference. The highest cyanide concentration (1.18 ± 0.2316 mg/kg) was recorded in raw potatoes at pH 8.6. The lowest cyanide concentration (0.26 ± 0.0034 mg/kg) was recorded in boiled Irish potato at pH of 6.2. Among the processed samples, the roasted Irish potatoes recorded the highest value of cyanide concentration (1.12 ± 0.0289 mg/kg) at pH of 8.6 followed by parboiled (1.05 ± 0.0600 mg/kg) Solanum tuberosum at pH 8.6 and then baked (0.79 ± 0.1179 mg/kg) Irish potato at pH 7.8. The highest mean cyanide concentration (0.83 mg/kg) was recorded at pH 8.6 (basic medium) while the lowest mean cyanide concentration (0.54 mg/kg) was recorded at pH 5.6 (acidic medium). These values were lower than World Health Organization (WHO) and International Standard Organization (ISO) maximum accepted standard of 10 mg of HCN /10 kg body weights). This study however provides information on the toxicity level of cyanide in raw and processed potatoes. It also shows that the processing methods can further lessen the cyanogen potentials of potatoes