Quantifying onion flavor compounds responding to sulfur fertility: sulfur increases levels of alk(en)yl cysteine sulfoxides and biosynthetic intermediates.

摘要: Three onion (Allium cepa L.) cultivars were grown to maturity at five S fertility levels and analyzed for S- alk(en)yl-L-cysteine sulfoxide (ACSO) flavor precursors, γ- glutamyl peptide (γ- GP) intermediates, bulb S, pyruvic acid, soluble solids content. ACSO concentration composition changed with fertility, the response was cultivar dependent. At treatments that induced deficiency symptoms during active bulbing, (+)S-methyl-L-cysteine dominant precursor, pathway a strong sink available S. As increased luxuriant levels, trans(+)-S-(1-propenyl)-L-cysteine (PRENCSO) became ACSO. (+)S-propyl-L- cysteine found in low relative total all treatments. With rapidly metabolized GP s detected. increased, especially L-glutamyl-S-(1-propenyl)-L-cysteine sulfoxide, penultimate compound leading synthesis. Nearly 95% of could be accounted measured compounds fertility. However, highest treatment, only 40 % attributed GP, indicating other significant reservoirs onions. Concentrations enzymatically produced acid (EPY) most closely related PRENCSO concentrations. Understanding dynamics accumulation vegetable Alliums will become increasing important as food phytomedicinal industries move toward greater product standardization characterization.