Cyanide is a chemical compound from the Cyano group, which consists of 3 carbon atoms that are bonded to nitrogen (C = N), and combined with other elements such as potassium or hydrogen. Specifically, cyanide is a CN– anion . These compounds exist in the form of gas, liquid (liquid) and solid (salt). The word “cyanide” comes from Greek which means “blue” which refers to hydrogen cyanide which is called Blausäure (“blue acid”) in Germany (Cahyawati, 2017).
Cyanide is a group of compounds containing cyano groups (-CN=) which are present in different forms (Kjeldsen 1999, Luque-Almagro et al. 2011). Cyanide in nature can be classified as free cyanide, simple cyanide, cyanide complex and cyanide derivative compounds (Smith and Mudder 1991).
Cyanide is a poisonous substance that can have various harmful effects. Cyanide can harm the heart and brain because these two organs use a lot of oxygen which can be inhibited from supplying when exposed to cyanide. Humans who drink water containing cyanide can become poisoned. This is because the cyanide that is absorbed by the stomach will inhibit the formation of a respiratory enzyme, namely cytochrome oxidase. The inhibition of the formation of this enzyme will cause anoxia (disorders of oxygen metabolism) in body cells. If the dose is large enough (0.54 mg HCN / kg body weight) it will result in death (Tsani, 2018).
Cyanide acid compounds are completely soluble in water, and are slightly soluble in ethanol. Plants containing cyanide are also poisonous, because they have 3 double bonds [: C≡N:] which ionize in the water. Not all cyanide compounds are toxic. Toxic compounds are compounds that can release free cyanide ions from their compounds.
Cassava peels have a high cyanide content. Based on the research results of the Bogor Agricultural Products Industry Center, cassava also contains unwanted and toxic elements, namely cyanide (HCN). The HCN content in cassava can affect the taste of the cassava (Suprapti, 2002). Sweet-tasting tubers yield at least 20 mg of HCN per kilogram of fresh tubers, and 50 times as much for those with bitter tasting. In this study, the researchers examined the cyanide content of the cassava peel. From the laboratory test results, we cannot conclude that the taste of the cassava obtained was seen from the cyanide content, because it was not the fruit / flesh of the cassava that was examined but the skin. The HCN compound itself is a type of poison that works very quickly. Death can occur within minutes if the HCN is swallowed with an empty stomach. HCN in liquid form can be absorbed by the skin and mucosa. The lethal dose of HCN in humans is around 60- 90 mg (Muhlisin, 2014).
This HCN compound can be reduced by processing such as drying, bleaching and boiling. Cassava itself actually contains the enzyme rhodanase which can detoxify HCN by forming thiocyanate. However, this natural detoxification cannot eliminate HCN effectively (Arisman, 2008). Rhodanase enzyme will catalyze the transfer of sulfur from thiosulfate compounds to cyanides which will form nontoxic thiocyanate compounds (Cipollone, 2008). HCN compounds are volatile in the boiling, steaming and other cooking processes, due to the nature of HCN which is volatile at room temperature, has a distinctive smell of HCN, and is easy to diffuse (Putra, 2009).
Fermentation causes the breakdown of linamarin compounds into free cyanide due to the activity of the linamarase enzyme from cassava tubers (Yeoh, 1998). The reduction of HCN by the fermentation method is due to an increase in the concentration of microorganisms during constant fermentation, which accelerates the breakdown of cyanogenic glycosides (Rusulu, 2012). The longer the immersion process, the higher the percentage reduction in HCN levels.