Organic and conventional fertilisation procedures on the nitrate, antioxidants and pesticide content in parts of vegetables

Abstract

Different parts of plant foods are generally discarded by consumers such as peel, stalk and leaves, which could however possess a nutritional value. However, few studies have analysed the composition of these marginal foods. The phenolic compound, flavonoid, polyamine, nitrate and pesticide contents of parts of vegetables that are usually discarded – but which were cultivated according to conventional and non-conventional procedures – were analysed to provide suggestions on how to improve the consumption of these parts and to reduce the production of urban solid waste. Few, but significant, differences between the two manuring procedures were observed. Higher nitrate content and the presence of organochlorine pesticides were found in conventional cultivated papaya peel, lemon balm leaves, jack fruit pulp, and beet stalk and peel. Discarded parts of plant foods such as stalk, leaves and peels can be used as a source of antioxidant compounds, such as phenolic compounds.

Keywords:

• phenolic flavonoids
• polyamine
• organochlorine
• peel
• stalk
• leaves

Acknowledgements

The authors would like to acknowledge the financial support from the SANTANDER and FAPESP (Fundação de Amparo a Pesquisa do Estado de São Paulo) (2006/55985-8; 2012/07218-9).