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Control of glucosinolate hydrolysis for enhanced bioactivity |
E. H. JEFFERY, Q. Qiao, and N. V. Matusheski. Dept. of Food Science & Human Nutrition, Univ. of Illinois, Urbana-Champaign, 905 S. Goodwin Ave., 499 Bevier Hall, MC 182, Urbana, IL 61801 Cruciferous vegetables are not only a source of vitamins, minerals and fiber, but they also offer protection from cancer. Anticarcinogenic activity depends upon the biological activity of several small molecules called isothiocyanates, the most potent of which is thought to be sulforaphane. Fresh broccoli contains little or no sulforaphane unless it is chopped or crushed. Crushing the plant cells brings a thioglucoside glucohydrolase enzyme, myrosinase, into contact with a series of thioglucoside secondary metabolites, the glucosinolates. Myrosinase catalyzes the cleavage of glucose and the resulting intermediates rearrange to form one of several products, the most common of which are isothiocyanates and nitriles. Hydrolysis of the glucosinolate glucoraphanin, found in highest concentration in broccoli, releases the potent bioactive isothiocyanate sulforaphane or a relatively inactive sulforaphane nitrile. Crop development to enhance the health benefit of broccoli has focused on identification of broccoli varieties high in glucoraphanin. However, glucoraphanin hydrolysis in crushed broccoli favors nitrile formation, with as little as 5- 15 % of the glucoraphanin yielding bioactive sulforaphane. Processing technology is needed to optimize sulforaphane formation and enhance the health benefit from dietary broccoli. Supported by a grant from the USDA/NRI.
Session 3, Control of endogenous enzymes in foods: A practical approach
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