Peer review

Dilute solutions of formaldehyde were used to inactivate the tannins in high-tannin (bird-resistant) sorghum. By means of this treatment it was shown that high-and low-tannin sorghums contain similar proportions of the different classes of protein. The differences observed in protein yield, when high-tannin sorghums are extracted (without pretreatment) by using the Landry and Moureaux fractionation are due to interactions between tannins an albumin, globulin, and prolamin proteins, the majority of these proteins being rendered insoluble in their usual solvents. In addition, electrophoresis indicated that those proteins which were extractables from high-tannin sorghum were bound to tannins. As formaldehyde facilitated the quantitative extraction of proteins from high-tannin sorghum it is suggested that it may have a more genera application in the study of proteins from plant material rich in polyphenols.

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