Betalains in beetroot and prickly pear fruit
- 11.02.2005
- Print-Artikel
- Redaktion
H. Schmandke, Nuthetal
Red and yellow beet and prickly pear fruit (Opuntia ficus indica) contain betalains, i.e. betacyanins and betaxanthins. Major compounds are betanin (up to 600 mg/kg pulp) and vulgaxanthin I in red beet, vulgaxanthin I in yellow beet, and indicaxanthin (up to 300 mg/kg pulp) and betanin (up to 190 mg/kg pulp) in prickly pear fruit.The stability of betalains is influenced by temperature und pH. The aglycone betanidin is produced by acidic hydrolysis of betanine, while decarboxylized betanine is produced by heat treatment. Betalamic acid and proline are obtained by alkaline hydrolysis of indicaxanthine.
Betanin applied by the oral route is poorly absorbed (urinary excretion ~ 4 %). The absorption rate of indicaxanthin is 20 times higher than that of betanin (urinary excretion ~ 76 %). Degradation products have not been detected in plasma, liver and urine. Suspensions of colon content metabolized about 30 % of the betanin added; degradation products have not been identified so far.
Betanin, betanidin, vulgaxanthin I and indicaxanthin have been found to show antioxidative effect in vitro and in biological systems such as human LDL, for instance. As far as resistance of LDL to copper induced oxidation is concerned, indicaxanthin was most effective.
In vivo (healthy humans), daily administration for two weeks of betanin and indicaxanthin reduces oxidative stress, as demonstrated by reduction of malondialdehyde and 15-F2t isoprostane in plasma and by decrease of hydroperoxides in LDL. The improved body redox status by betalains may reduce the risk of age related and degenerative diseases such as arteriosclerosis and cancer (skin and lung).
Keywords: Betalains / beetroot / prickly pear fruit
Sie finden den Artikel in deutscher Sprache in Ernährungs-Umschau 02/05 ab Seite 56.
