A rapid and inexpensive enzymatic assay for total cyanide in cassava (Manihot esculenta Crantz) and cassava products.

Ikediobi, Christopher O.; Onyia, G. O. C.; ELUWAH, C. E.

doi:10.1271/bbb1961.44.2803

Cited by 52 publications

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“…Linamarase in recent years has been introduced for the quantitative determination of cyanide in cassava and its products (Ikediobi et al 1980). The methodology involves hydrolyzing all cyanogenic glucosides to release HCN.…”

Section: Introductionmentioning

confidence: 99%

PURIFICATION AND SOME PROPERTIES OF LINAMARASE FROM CASSAVA (Manihot esculenta) CORTEX

Nok

Ikediobi

1990

J Food Biochemistry

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The enzyme linamarase (E. C. 3.2.1.21) has been purijied from cassava cortex (Manihot caculenta) by techniques involving acetone precipitation, ammonium sulfate fractionation, gel jiltration and ion-exchange chromatography.Two peaks of linamarase activity (A & B ) were eluted by linear gradient on DEAE-Sephadex column. Both forms of the enzyme were found to catalyze similar reactions, however, at different rates. Double reciprocal plots from initial velocity data gave K,,, of I .47 mM & I .44 mM for linamarase A & B, respectively, with linamarin as substrate. The K,,, values with the artijicial substrate paranitrophenyl glucoside (PNP-G) were 0.48 mM. Both enzyme forms exhibited maximal activity at pH 6.0 and 30°C.Arrhenius plots gave activation energy (E,) as 49 for linamarase A & B , respectively. Analysis of cyanide levels in cassava and its products with the crude enzyme showed the leaves to contain high levels of the toxic factor.

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Section: Introductionmentioning

confidence: 99%

PURIFICATION AND SOME PROPERTIES OF LINAMARASE FROM CASSAVA (Manihot esculenta) CORTEX

Nok

Ikediobi

1990

J Food Biochemistry

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“…The clarification of extracts of cassava products requires filtration or centrifugation (Cooke, 1979;Ikediobi et al, 1980). However, gelatinized starch in processed cassava products tended to encourage extensive gel formation which hindered filtration.…”

Section: Effect Of Starch Gelatinization On Total Cyanide Determinationmentioning

confidence: 99%

“…Cooke and co-workers developed a method using the purified enzyme linamarase for estimating total cyanide in cassava products (Cooke, 1978(Cooke, ,1979Cooke, Blake & Battershill, 1978). Ikediobi, Onyia & Eluwah (1980) ing enzymic hydrolysis of cyanogenic glucosides) with the well known but less specific alkaline picrate method. This obviated the need for the rather more complex chemicals used in the former method, and the need for a fume cupboard.…”

Section: Introductionmentioning

confidence: 99%

“…The authors claimed that a trained operator could analyse at least 700 samples/day, yet Rao & Hahn (1984), who recently automated the Cooke method using an autoanalyser, claim only 300 samples/ day. The method of Ikediobi et al (1980), however, has not been applied to cassava products which have undergone non-enzymic browning (NEB), which produce very viscous extracts or which contain high levels of reducing sugars (e.g., fermentation products). The present paper outlines the effect of NEB pigments and sugars on total cyanide levels determined by the enzymic assay procedure of Ikediobi et al (1980).…”

Section: Introductionmentioning

confidence: 99%

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Effect of non‐enzymic browning, starch and sugars on total cyanide determination in cassava by an enzymic assay

Arihantana

Buckle

1986

Int J of Food Sci Tech

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Maillard (non-enzymic) browning pigments and gelatinized starch interfered in the assay of total cyanide in cassava products by an alkaline picrate-enzymic method. Interference from browning pigments in cyanide determinations was overcome by adding charcoal followed by filtration, while gelatinized starch was precipitated by the addition of ethanol. Glucose, fructose and maltose but not sucrose also interfered in the assay and produced high total cyanide results. A more specific reaction than alkaline picrate is still required for free cyanide estimations in cassava products.

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“…This objective has been achieved in the present work. At the same time it has also proved possible to produce a semiquantitative method for use in the laboratory, based on elution of the picrate paper and spectrophotometry (Indira and Sinha 1969 ;Ikediobi et al 1980 ;Williams and Edwards 1980).…”

Section: Introductionmentioning

confidence: 99%

Simple picrate paper kit for determination of the cyanogenic potential of cassava flour

Egan

Yeoh

Bradbury

1998

J. Sci. Food Agric.

111

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A simple picrate paper kit method was developed for the semiquantitative determination of the cyanogenic potential for cassava flour. The method involved the addition of linamarase and pH 8 phosphate buffer (absorbed in a filter paper disc) to 100 mg of flour +0·5 ml water placed in a small vial. A rectangle of yellow picrate paper attached to a plastic strip was added and the vial capped and left overnight. The yellow paper changed colour towards brown and its colour was compared with that of a standard colour card with 10 shades of colour which corresponded with cyanogenic potentials of 0–800 mg HCN equivalents kg−1 flour (ppm). To obtain a more accurate measure of cyanogenic potential (±20%) the paper was eluted with water and the absorbance measured at 510 nm. The cyanogenic potential in ppm was determined from a calibration graph. The methodology is available in kit form. The simple method may be used in the field by a relatively unskilled person. The more accurate method requires a spectrophotometer and is suitable for use in simple laboratories in developing countries. © 1998 SCI.

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A rapid and inexpensive enzymatic assay for total cyanide in cassava (Manihot esculenta Crantz) and cassava products.

Cited by 52 publications

References 0 publications

PURIFICATION AND SOME PROPERTIES OF LINAMARASE FROM CASSAVA (Manihot esculenta) CORTEX

PURIFICATION AND SOME PROPERTIES OF LINAMARASE FROM CASSAVA (Manihot esculenta) CORTEX

Effect of non‐enzymic browning, starch and sugars on total cyanide determination in cassava by an enzymic assay

Simple picrate paper kit for determination of the cyanogenic potential of cassava flour

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