Cereal Chem 66:87-89   |  VIEW ARTICLE

Effect of Cultivar, Steeping, and Malting on Tannin, Total Polyphenol, and Cyanide Content of Nigerian Sorghum.

B. A. Osuntogun, S. R. A. Adewusi, J. O. Ogundiwin, and C. C. Nwasike. Copyright 1989 by the American Association of Cereal Chemists, Inc. 

Tannin was estimated in the seeds of 15 Nigerian sorghum cultivars and found to vary between 0.25% (catechin equivalent) for SSV11 and SSV12 and 2.92% for SRN484. Total polyphenol content ranged from 0.32% (tannic acid equivalent) for KSV13 to 2.7% for SRN484. During steeping (48 hr), the extractable tannin content of SRN484, KSV7, and SSV3 decreased 33, 27, and 43%, respectively; during malting (five days) the tannin content decreased an additional 42, 24, and 10%, respectively. Total extractable polyphenol content of SRN484 and SSV3 was reduced by 41 and 20% during steeping, whereas that of KSV7 was increased by 50%. The polyphenol content also decreased by 22, 68, and 19% for SRN484, KSV7, and SSV3, respectively, after malting. Cyanide content of the grains varied from 8 micrograms/g for SSV3 to 38 micrograms/g for SRN484. After steeping, the cyanide content increased to 44 micrograms/g for NVW cultivar and 111 micrograms/g for SRN484, whereas the cyanide content of the five samples investigated increased during malting to reach 121, 99, 105, 136, and 78 micrograms/g for SRN484, SSV11, KSV8, KSV15, and NVW, respectively. The results suggested that all the sorghum cultivars except SRN484 could be used in the brewing industry although care should be taken about the cyanide component of the malt.