Effects of ripening stage and cultivar on quality parameters and carotenoids content of six tomato cultivars grown under organic conditions.

摘要

Six tomato cultivars were grown under organic conditions and harvested during 2008 season at three different ripening stages (turning, light-red and red). The studied cultivars were 'BGV-001000', 'BGV-003524', 'MU-L-15', 'MU-L-24' and 'MU-L-36' (Spanish traditional cultivars) and 'Baghera' (commercial cultivar). Total soluble solids content (TSS), pH, titratable acidity (TA), skin colour and carotenoids (lycopene and beta -carotene) were assessed on each cultivar at the three ripening stages. The highest TSS content was found in all cultivars harvested at the red stage, except in 'MU-L-36', being 'Baghera' the cultivar having the highest value (5.55 degrees Brix). The maximum TA was found in 'MU-L-24' (0.37% citric acid at the turning stage), while the minimum was measured in 'BGV-003524' (0.26% citric acid at the light-red stage). Regarding colour, significant differences were found between cultivars in the mean values of L*, a*, b*, a*/b*, chroma and hue angle. During ripening, L* and hue decreased, while a* and a*/b* increased in all cultivars. The a*/b* ratio showed significant differences between the three stages in all cultivars. The highest (1.74) and the lowest (-0.15) a*/b* values were found in 'BGV-003524' in red and turning stages, respectively. During ripening, lycopene contents changed widely among all cultivars, increasing significantly from 6.57 mg/kg fwt in 'BGV-003524' (turning stage) to 132.64 mg/kg fwt in 'MU-L-24' (red stage). In general, beta -carotene was highly accumulated at the light red-stage, ranging the concentrations between 5.66 and 16.75 mg/kg fwt. Most of the studied parameters were greatly correlated (p<0.01). In summary, our study showed that 'BGV-003524', 'MU-L-15' and 'MU-L-36' presented quality parameters similar or better than the commercial cultivar. At the last stages, all traditional tomatoes were richer in lycopene than commercial one. The results obtained suggest that traditional tomatoes can be recommended for organic production.