food products oils and fats application_number US 22650981 A description in accordance with one embodiment of this invention isoflavones having the structure str7 wherein the dashed lines may be carbon carbon single bonds or carbon carbon double bonds and wherein x may be two hydrogen atoms or oxygen and further wherein r r 39 and r 34 may be a methyl or ethyl group or hydrogen have been found to be useul as antioxidants and as components of antioxidant compositions certain of these compounds namely those having the structure str8 are natural products which may be recovered from tempeh an indonesian foodstuff by fermentation of soybeans with a fungus e g either rhizopus oligosporus atcc no 22959 or rhizopus oryzae atcc no 9363 compounds ii are typically present as a mixture in tempeh and are most readily recovered therefrom in the form of a mixture from which the individual compounds can subsequently be isolated compounds encompassed within structure ii as well as within the other structures herein may include stereoisomers and optical isomers for purposes of this disclosure no distinction will be made among such isomers so that it is to be understood that the disclosure and claims set forth hereinafter embrace all of the isomers encompassed within the structural formulas indicated certain of compounds ii are known compounds such as for example texasin 6 7 dihydroxy 4 39 methoxyisoflavone genistein 5 7 4 39 trihydroxy isoflavone daidzein 7 4 39 dihydroxyisoflavone glycitein 6 methoxy 7 4 39 dihydroxyisoflavone and the so called 34.