EVALUATION OF THE DEGRADATION OF SORGHUM CONDENSED TANNINS BY A PENICILLIUM SP BY DETERMINATION OF PROANTHOCYANIDINS AND FLAVAN-3-OLS

A penicillium sp strain selected among several molds obtained by an en richment culture technique using plant materials in decomposition is a ble to degrade relatively pure sorghum condensed tannin of SVR8 and SV R157 varieties. This biodegradation has been followed by two specific methods measuring proanthocyanidins and flavan-3-ols. Fermentations we re conducted in an aqueous mineral medium with 0,1 g/l of glucose and another without glucose. The diminution of tannins expressed as proant hocyanidins and flavan-3-ols was significantly different (p<0,001) in both media, after 48 h. Depolymerisation was also significantly differ ent between the two media for both tannin varieties. The percentage of degradation of proanthocyanidins reached 27,2% and 49,3% for SVR8, 21 ,2% and 40,5% for SVR157 in the medium without glucose and with glucos e respectively. In the case of flavan-3-ols, the decreases were 20,5% and 23,5% for SVR8 (not significant) ; 29,7% and 49,4% for SVR157 (sig nificant). These results suggest the possible improvement of the nutri tive value of high tannin sorghum grain by fermentation.