Lam L.,University of Toronto |
Soong R.,University of Toronto |
Sutrisno A.,University of Toronto |
De Visser R.,IsoLife BV |
And 15 more authors.
Journal of Agricultural and Food Chemistry | Year: 2014
Seeds are complex entities composed of liquids, gels, and solids. NMR spectroscopy is a powerful tool for studying molecular structure but has evolved into two fields, solution and solid state. Comprehensive multiphase (CMP) NMR spectroscopy is capable of liquid-, gel-, and solid-state experiments for studying intact samples where all organic components are studied and differentiated in situ. Herein, intact 13C-labeled seeds were studied by a variety of 1D/2D 1H/13C experiments. In the mobile phase, an assortment of metabolites in a single 13C-labeled wheat seed were identified; the gel phase was dominated by triacylglycerides; the semisolid phase was composed largely of carbohydrate biopolymers, and the solid phase was greatly influenced by starchy endosperm signals. Subsequently, the seeds were compared and relative similarities and differences between seed types discussed. This study represents the first application of CMP-NMR to food chemistry and demonstrates its general utility and feasibility for studying intact heterogeneous samples. © 2013 American Chemical Society. Source
Gorissen A.,IsoLife BV |
Kraut N.U.,University of Groningen |
De Visser R.,IsoLife BV |
De Vries M.,University of Groningen |
And 2 more authors.
Food Chemistry | Year: 2011
The isothiocyanate sulforaphane, present in significant amounts in broccoli (Brassica oleracea L.) seedlings in the form of its precursor glucoraphanin, has been identified as an inducer of quinine reductase, a phase-II detoxification enzyme known for its anticarcinogenic properties. Its concentration in broccoli seedlings usually decreases during the first 7-14 days after germination. No conclusive data on sulforaphane metabolism in seedlings are available in the literature. Here, we unambiguously demonstrate in 12C/ 13C-cross experiments that sulforaphane is not biosynthesised de novo during the first week of seedling development. Both 12C (99 atom% 12C) and 13C (98 atom% 13C) broccoli seeds were produced and subsequently germinated and grown either in a 13CO 2 or a 12CO 2 environment. Afterwards, the labelling degree of sulforaphane in seeds and in seedlings was analysed by HPLC-MS. We conclude that sulforaphane exclusively originates from seed reserves and that de novo biosynthesis is not detectable (<1%) in broccoli seedlings. © 2011 Elsevier Ltd. All rights reserved. Source