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| Credit of photo: nt.gov.au |
Organically grown tomatoes may be more valuable than those grown conventionally as they contain higher levels of beneficial compounds, according to a new study published in the journal of Agricultural and Food Chemistry.
Organic crops are widely viewed as nutritionally superior to their counterparts grown conventionally.
Not every one believes in organic food, but studies have indeed found more nutrients in organic tomatoes and other plant foods.
In the study, Alyson Mitchell from the University of California-Davis, and researchers from University of Minnesota tested two naturally occurring antioxidants quercetin and kaempferol aglycones in dried tomato samples grown and processed conventionally or organically between 1994 and 2004.
Ten-year mean levels of quercetin and kaempferol in organic tomatoes (115.5 and 63.3 mg per gram of dry matter) were 79 and 97% higher than those in conventional tomatoes (64.6 and 32.06 mg per gram of dry matter), the study found.
In addition, the levels of flavonoids increased over time in samples from organic treatments, but in the samples conventionally grown. These compounds increased as soil organic matter accumulation increased in organic plots and manure application rates decreased.
Mitchell's group also reported in 2006 in the same journal that "Significantly higher levels of percent soluble solids (17%), quercetin (30%), kaempferol (17%), and ascorbic acid (26%) were found in
Burbank tomatoes (fresh weight basis; FWB), whereas only levels of percent soluble solids (10%) and kaempferol (20%) were significantly higher in organic Ropreco tomatoes (FWB)."
The superiority of organic tomatoes was also reported in the October 2004 issue of the journal of Agricultural and Food Chemistry by Caris-Veyrat C and colleagues in
France.
The researchers found that fresh organic tomatoes contained higher vitamin C, carotenoids, and polyphenol contents (except for chlorogenic acid) than conventional tomatoes.
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Primary source:
Journal of Agricultural and Food Chemistry, June 2007
"Ten-Year Comparison of the Influence of Organic and Conventional Crop Management Practices on the Content of Flavonoids in Tomatoes"
A.E. Mitchell, Y.-J. Hong, E. Koh, D.M. Barrett, D. E. Bryant, R.F. Denison, and S. Kaffka
