Metabolismo antioxidante e qualidade durante a maturação de frutos tropicais produzidos pelos sistemas de produção orgânico e convencional

Abstract

The growth of the organic cultivation of vegetables is driven by consumers seeking healthier foods free of pesticides and chemical fertilizers. Thus the aim of this study was to evaluate changes in quality and antioxidant metabolism during fruit ripening of five species that have economic importance grown by organic farming systems and conventional. The yellow passion fruit, banana, tomato, sugar apple and acerola cultivated under organic and conventional farming were manually harvested at different stages of development, the pulp were processed and stored at 18 °C. The results indicate that the organic cropping system induced stress in passion fruit as shown by the greater degree of peroxidation and lowest phenolic content and CAT activity, however it stimulated vitamin C. The higher SOD and PAL activities indicate that organic bananas suffered an oxidative stress, but their nutritional quality parameters were not affected. The organic farming system also induced stress in tomato evidenced by the greater degree of lipid peroxidation and increased PAL and SOD activities, but also positively influenced all nutritional antioxidants components. Although the present results for sugar apple do not allow a comparison between cropping systems, there are strong indications that the organic cropping system did not induce stress in sugar apple. For acerola BRS 235, there are signs that organic system induced an oxidative stress due to the higher lipid peroxidation degree. As the data obtained, the organic system induced stress in passion fruits, tomato, banana and acerola. The organic cropping system positively influenced the non-enzymatic antioxidants in yellow passion fruit and tomatoes, however for the others fruits, there was no influence or it was negative, as in acerola. Therefore, it can be concluded that stress induced by organic cropping system will not necessarily stimulate the production of antioxidant compounds.