Premium
Picrate paper kits for determination of total cyanogens in cassava roots and all forms of cyanogens in cassava products
Author(s) -
Bradbury Meredith G,
Egan Sylvia V,
Bradbury J Howard
Publication year - 1999
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(19990315)79:4<593::aid-jsfa222>3.0.co;2-2
Subject(s) - picrate , chemistry , cyanogen , hydrolysis , acetone , chromatography , organic chemistry , ion
The simple semiquantitative picrate method for the determination oftotal cyanogens in cassava flour has been modified by increasing theconcentration of the picrate solution used to make up the picratepapers, such that a linear Beer's Law relation betweenabsorbance and cyanogen content is obtained over the range0–800 mg HCN equivalents kg −1 cassava. Themethod has been adapted to determine the total cyanogen content ofcassava roots and the results compared using the picrate method andthe acid hydrolysis method for six different roots from fivecultivars. The agreement between the results is satisfactory. Thesimple method for determination of total cyanogens in cassava rootsin the field is available in kit form. The methodology has beenmodified to allow determination of the three different forms ofcyanogens present in cassava flour, viz HCN/CN − ,acetone cyanohydrin and linamarin. HCN/CN − isdetermined by the picrate method in which cassava flour is reactedwith 0.1 M sulphuric acid for 3 h at room temperature.HCN/CN − plus acetone cyanohydrin is alsodetermined by the picrate method after treating cassava flour with4.2 M guanidine hydrochloride at pH 8 for 3 h at roomtemperature. A comparison has been made of the amounts of the threecyanogens present in six cassava flour samples using thesemiquantitative picrate and the acid hydrolysis methods. Theagreement between the two methods is satisfactory, which shows thatthe new methodology works well. The picrate method for determinationof the three cyanogens in cassava flour is also available as a kit. © 1999 Society of Chemical Industry