Qualidade físico-química e sanitária de tomate cereja e milhoverde, cultivados em sistemas de produção orgânico e convencional

The objective of this study was to evaluate the quality of the cherry tomatoes and green corns grown under organic and conventional conditions. The samples of cherry tomatoes were obtained from the Instituto de Ciencias Agrarias - UFMG, in the town of Montes Claros . MG (Brazil), applying a completely randomized design, consisting of a 2 x 2 factorial corresponding to 2 harvest dates (30 and 45 days after the appearance of the first ripe fruit) and 2 cultivation systems (organic and conventional), with five replicates. The samples of green corn were obtained from EMBRAPA Milho e Sorgo, Sete Lagoas . MG (Brazil), in the 2007/2008 season. A completely randomized design with three repetitions was applied; the treatments were arranged in a 4 x 2 factorial, corresponding to 4 cultivars (AG 1051, BR 106, 551 and VIVI SWB) in 2 cultivation systems (organic and conventional). The agronomic characteristics of green corn were determined. The samples of cherrytomatoes and green corn were characterized according to their physicalchemical properties, proximate composition, content of carotenoids, and levels of biogenic amines. They were also evaluated on the microbiological and parasitologic patterns. In the analysis of agronomic characteristics the cultivars generally showed good production of green corn in organic system. The tomatoes harvested at 30 days presented lower values of soluble solids and total carotenoids when compared to those collected at 45 days. Fruits resulting from organic production have a higher level of carotenoids. The average values of L* were higher in tomatoes produced in the conventional system. In green corn samples, the average values of pH, titratable total acidity, a*, carbohydrate, total energy value, and of À-carotene were higher inthe grains of green corn grown under the organic system. The grains of green corn of the cultivars AG1051, BR 106 and SWB 551 also presented a higher level of ether extract in the organic system. The same trend could be observed in the level of total carotenoids for the cultivars BR 106 and SWB 551, as well as b* for AG 1051. The cultivar SWB 551 showed a better performance regarding the characteristics of total soluble solids, À-carotene, chroma b*, and also regarding the levels of ether extract and total carotenoids in fruits from organic system when compared to other cultivars. Regarding the sanitary quality of the samples, it was found that the count of yeasts and molds in cherry tomatoes was higher in the organic system. In the analyses of bioactive amines, the presence of cadaverine, putrescine, spermine and spermidine was detected in the samples of green corn; putrescine, tyramine, histamine, serotonin, agmatine, spermidine, spermine and tryptamine were detected in the samples of cherry tomatoes. VIVI SWB and 551 sweet corns showed higher levels of amines. In general, the analyzed vegetables presented a trend of having higher levels of biogenic amines in fruits produced under the organic system. Therefore, the quality of the fruit may be affected according to the production system, cultivars used and harvest dates.Nevertheless, further studies are needed to evaluate the same effect in other food sources, especially vegetables.