000 | 05213nab a22006497a 4500 | ||
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001 | 39649 | ||
003 | CO-PlCIA | ||
005 | 20130510180942.0 | ||
040 |
_aCO-PlCIA _cCO-PlCIA |
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041 | _aeng | ||
050 | _a41190 | ||
245 | _aImproved enzymic assay for cyanogens in fresh and processed cassava | ||
100 | _aO'Brien, G.M. | ||
700 | _aTaylor, A.J. | ||
700 | _aPoulter, N.H. | ||
008 | 120504t1991 000 0seng d | ||
300 | _a56(2):277-289 | ||
520 |
_aSe modifico el ensayo para cianogenos de yuca desarrollado por el Instituto de Recursos Naturales para asi superar algunos de los problemas encontrados cuando el ensayo se aplica a productos de la yuca. La inclusion de 25 por ciento de etanol en el medio de extraccion aumento el vol. de extracto recuperado de los productos de la yuca procesados al calor, elimino la necesidad de centrifugacion y no interfirio con ningun aspecto del ensayo. Se observo una mayor recuperacion de cianohidrina y se cambio la estimacion del contenido de cianogenos para considerar el vol. total del extracto. Se logro el examen de los 3 cianogenos (glucosido, cianohidrina y cianuro libre) por separado mediante el uso de alicuotas del extracto como tampon seguido del tratamiento apropiado. Se demostro la importancia del analisis del cianuro libre (HCN) a pH 4. Por encima de este valor de pH, la degradacion de cianohidrina tambien produce cianuro libre, suscitando valores equivocos. Se determino la eficiencia del medio de extraccion para recuperar la linamarina y la cianohidrina adicionadas a partir de productos alimenticios derivados de la yuca. Se mejoro la recuperacion de cianohidrina utilizando medio acido/etanol. Se examino la estabilidad de los cianogenos en el medio de extraccion acido/etanol a temp. ambiente y temp. de refrigeracion. Durante un periodo de 2 meses, los extractos refrigerados mostraron una variacion aceptable en comparacion con la variacion normal dentro del ensayo (5 por ciento) para los cianogenos totales y no glicosidicos pero los niveles de cianuro libre presentaron grandes disminuciones (perdidas de 15-56 por ciento). Puesto que falta determinar la toxicidad relativa de los 3 cianogenos, la cantidad relativa de cada cianogeno puede ser importante al evaluar la seguridad de los productos de la yuca. (RA-CIAT) _9spa |
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520 |
_aThe assay for cassava cyanogens developed at the Natural Resources Institute has been modified to overcome some of the problems encountered when the assay is applied to cassava products. Inclusion of 25 percent ethanol in the extraction medium increased the volume of recovered extract from heat-processed cassava products, eliminated the need for centrifugation and did not interfere with any aspect of the assay. Greater cyanohydrin recovery was noted and the calculation for cyanogen contents was changed to take into account the total extract volume. The separate assay of the three cyanogens (glucosides, cyanohydrins and free cyanide) was achieved by buffering aliquots of the extract followed by appropriate treatment. The importance of assaying for free cyanide (HCN) at pH 4 was demonstrated. Above this pH, cyanohydrin degradation also produces free cyanide, giving rise to misleading values. The efficiency of the extraction medium in recovering added linamarin and cyanohydrin from cassava foods was determined. Recoveries of cyanohydrin were improved using the ethanol/acid medium. The stability of the cyanogens in the ethanol/acid extraction medium was tested at ambient and refrigeration temperatures. Over a two-month period, refrigerated extracts showed acceptable variation as compared with normal variation within the assay (5 percent) for total and non-glycosidic cyanogens but the levels of free cyanide showed heavy losses (15-56 percent lost). Since the relative toxicities of the three cyanogens have yet to be ascertained, the relative amount of each cyanogen may be important when assessing the safety of cassava products. (AS) _9eng |
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650 |
_aManihot esculenta _9eng |
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650 |
_aCyanides _9eng |
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650 |
_aEnzymes _9eng |
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650 |
_aHCN CONTENT _9eng |
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650 |
_aAnalysis _9eng |
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650 |
_aLINAMARIN _9eng |
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650 |
_aLINAMARASE _9eng |
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650 |
_apH _9eng |
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650 |
_aGARI _9eng |
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650 |
_aStorage _9eng |
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650 |
_aTemperature _9eng |
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650 |
_aClimatic requirements _9eng |
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650 |
_aCOMPOSITION _9eng |
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650 |
_aCultivation _9eng |
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650 |
_aCYANOGENIC GLUCOSIDES _9eng |
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650 |
_aFOOD PRODUCTS _9eng |
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650 |
_aStarch crops _9eng |
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650 |
_aUses _9eng |
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650 |
_aManihot esculenta _9spa |
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650 |
_aCianuros _9spa |
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650 |
_aEnzimas _9spa |
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650 |
_aCONTENIDO DE HCN _9spa |
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650 |
_aANALISIS _9spa |
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650 |
_aLINAMARINA _9spa |
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650 |
_aLINAMARASA _9spa |
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650 |
_apH _9spa |
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650 |
_aGARI _9spa |
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650 |
_aAlmacenamiento _9spa |
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650 |
_aTemperatura _9spa |
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653 |
_aYuca _9spa |
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653 |
_aArtÃculos en revistas _9spa |
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653 |
_aJournal articles _9spa |
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653 |
_aCassava _9spa |
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773 |
_tJournal of the Science of Food and Agriculture _d1991 |
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998 | _aYUCA | ||
653 |
_aJournal article _9eng |
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942 |
_2lcc _cJA |
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999 |
_c77015 _d77015 |