The authentication of bamboo shoots found in the marketplace is complex because the chemical profile of processed and unprocessed material is different. During processing, heat derivatives of the potentially toxic cyanogenic glycoside taxiphyllin are produced. Here, we report the isolation and structure elucidation of the two major diarylbutenedinitrile derivatives, which are cis and trans isomers of the rare 2,3-bis(4-hydroxyphenyl)but-2-enedinitrile from a commercial extract of bamboo shoots. These compounds, absent in fresh bamboo shoots, were produced by boiling the shoots of Bambusa vulgaris and were associated with a decrease in levels of taxiphyllin. Furthermore, (E)-2,3-bis(4-hydroxyphenyl)but-2-enedinitrile was quantified in all 16 of the commercial products tested. Its abundance was found to be highly variable, ranging from 1 to 3 mg/g in preserved bamboo shoots and from 10 to 160 mg/mL in commercial aqueous extracts. Of the 15 authenticated bamboo samples tested for taxiphyllin, it was found only in the shoots of B. vulgaris and Gigantochloa verticillata, which represent two edible bamboo species. Our results indicate that diarylbutenedinitriles can be used as markers for the authentication of boil-processed bamboo shoots obtained from taxiphyllin-containing edible species and organs.
Keywords: authentication; bamboo shoots; diarylbutenedinitriles; quality control.