QUANTITATIVE-DETERMINATION OF THE GLUCOSINOLATES SINIGRIN AND PROGOITRIN BY SPECIFIC ANTIBODY ELISA ASSAYS IN BRUSSELS-SPROUTS

Glucosinolates from Brussels sprout samples were extracted using an ef fective concentration of 2% phosphoric acid followed by a neutralizati on step and heat treatment for removal of inactivated protein. The (po tentially) bitter glucosinolates sinigrin and progoitrin were found to be stable during this new extraction protocol. Antisera, as raised ag ainst hemisuccinate-linked glucosinolate conjugates, were very specifi c in sandwich. ELISA assays for their corresponding substrates. The EL ISA assays showed maximally 7.4% cross-reactivity to other aliphatic g lucosinolates and were log-linear from the nM to mu M range. In compar ison to the standard HPLC method, the sinigrin and progoitrin ELISA re spectively slightly and considerably overestimate the actual content o f these glucosinolates. The progoitrin content of samples as determine d either with the ELISA assay or by HPLC, however, is highly correlate d (r(2) = 0.92, n = 12, p < 0.01), suggesting that the former assay is also applicable for the screening of the progoitrin content in Brusse ls sprout samples.