Exit of seed weevil and its parasitoid changed testa color but not phenolic and tannin contents in faba beans

Abstract Seeds of eight faba bean accessions, grown under field conditions, were subjected to L * a * b * ( L *, lightness; a * redness; b * blueness) scale examination and phenolic and tannin determination after classification as intacts, bruchid- and parasitoid-damaged. Accessions differed in testa color and phenolic and tannin contents. L * and b * were negatively correlated with phenolics and tannins while a * was positively correlated with phenolics. Bruchid- and parasitoid-damaged seeds had increased a * indicating a shift of testa color tο red but phenolics and tannins did not differ between seed classes. Thus, testa discoloration in insect-damaged seeds was not the result of oxidation of phenolics but possibly due to Maillard reaction indicating accelerating aging of seeds.