Effect of peanut tannins on percent seed colonization and in vitro growth by Aspergillus parasiticus

The relationship between tannin content of mature, intact, cured peanut seed and percent seed colonization by Aspergillus parasiticus was examined. Tannin content in 9 cultivars, 7 of which were grown in both Tifton, Georgia and Puerto Rico, was significantly correlated with percent seed colonization. For data expressed as mg tannin/g intact seed and mg tannin/g seed coat, correlation coefficients with percent colonization were 0.74 and 0.76, respectively. Seed coat tannin, methanol-extracted, water-soluble material from peanut seed coats, was tested in vitro for effects on growth of A. parasiticus. As concentrations of tannins were increased to 7.5%, inhibition of fungal growth increased linearly to 88%; a concentration of 20% produced over 96% inhibition.