Agriculture Reference
In-Depth Information
Tomato Fruit Quality from Organic and Conventional Production
http://dx.doi.org/10.5772/58239
5,5
5,0
4,5
b a a
b a b
4,0
3,5
3,0
2,5
2,0
1,5
1,0
0,5
0,0
Amati
Robin
Elpida
Amati
Robin
Elpida
Organic Conventional
Figure 1. Lycopene content (mg 100g
-1
) Figure. 2 : Carotenoids content (mg 100g
-1
)
Figure 2.
Carotenoids content (mg 100g
-1
) in organic and conventional tomato cultivars
by activating their own defense mechanisms, increasing the levels of all antioxidants. The more
stress plants suffer, the more polyphenols they produce,' these authors point out [55]. Tomato
fruits from organic farming experienced stressing conditions that resulted in oxidative stress
and the accumulation of higher concentrations of soluble solids as sugars and other com‐
pounds contributing to fruit nutritional quality such as vitamin C and phenolic compounds [56].
Flavonoid content in tomatoes seems to be related to available N [34]. Plants with limited N
accumulate more flavonoids than those that are well-supplied. If differences in flavonoid
content reflect fundamental differences in the behavior of soil N between conventional and
organic systems, then the N available to tomatoes late in the season may have declined in
organic plots in recent years in response to the cumulative effects of a decrease in compost
application rates [57].
Interestingly, yellow flavonoids and anthocyanins did not follow the pattern of total phenolics
(Table 2). For instance, the concentration of yellow flavonoids was 70% higher in organic fruits
when compared to fruits from conventional growing system, but only at the harvesting stage,
which is consistent with similar observations previously [57]. The concentration in anthocya‐
nins was lower in the fruits from organic farming at all three stages of fruit development [56].
These discrepancies indicate that organic farming had the effect of modifying the levels of
transcripts or the activities of enzymes controlling intermediary steps of the biosynthetic
pathway of phenolic compounds. In spite of the changes in antioxidants, the total antioxidant
activity was not significantly different among the organic and conventional tomatoes (Table 2).
