Journal of Radioanalytical and Nuclear Chemistry, Vol. 270, No.1 (2006) 249–252 0236–5731/USD 20.00 Akadémiai Kiadó, Budapest © 2006 Akadémiai Kiadó, Budapest Springer, Dordrecht Evaluation of conventional and organic beans by instrumental neutron activation analysis L. G. C. Santos, E. A. N. Fernandes, M. A. Bacchi, F. S. Tagliaferro, S. M. Tsai Centro de Energia Nuclear na Agricultura (CENA/USP), P.O. Box 96, 13400-970, Piracicaba, Brazil (Received April 6, 2006) Beans are one of the most consumed foods in Brazil, having a high economic and social value for the country. This work aimed at the identification of chemical differences between conventionally and organically cultivated beans by instrumental neutron activation analysis. Sixteen chemical elements have been investigated, however, only Br, Ca, Co, Fe, K, Rb and Zn were above the detection limits in all samples, while Cs was above the detection limit in half the samples. The results indicated differences in chemical composition related to type of cultivation (conventional or organic), field localization and variety of beans. Introduction Several theories try to explain the origin and domestication of bean plants, however, it is a consensus that beans are among the oldest foodstuff, as can be observed in the first registers of the humanity history. In Brazil, beans are cultivated both in small and large fields, by various systems of production and in all geographic regions of the country, having an important economic and social role. Due the nutritional and therapeutical properties, beans are often used to fight hunger and malnutrition, as a rich source of nutrients. Both rice and beans are the base of the daily diet of Brazilian population. According to the Food and Agriculture Organization (FAO), Brazil is the largest producer of beans in the world, with 3 million metric tons (approximately 16% of the world production), followed by India and China. Considering the harvested area, Brazil is the second in the world, with 4 million hectares (approximately 15% of the world harvested area). 1 The use of fertilizers and pesticides associated with irrigation can be a source of environmental pollution, contaminating the food chain and eventually foodstuffs consumed by humans. 2 The large quantity of agrochemicals used in intensive agriculture may cause human and animal intoxication and environmental contamination. 3 As a consequence, the consumption of organically cultivated products increases as consumers begin to question the sustainability of the present agricultural model. There is no single definition accepted worldwide for organic agriculture. The International Federation of Organic Agriculture Movements (IFOAM) defines organic agriculture as “all agricultural systems that promote the environmentally, socially and economically sound production of food and fiber”. The joint FAO/WHO Codex Alimentarius Commission defines * E-mail: lgsantos@cena.usp.br organic agriculture as “a holistic production management system that promotes and enhances agro ecosystem health, including biodiversity, biological cycles, and soil biological activity”. 4 For a product to be commercialized as an “organic product”, it needs to be certified. Such a certification is supposed to represent a guarantee that the product, process or service complies with the requirements set by the organization issuing the document. Nevertheless, there is a clear lack of measurements able to objectively identify organic products out of the conventional ones. The development of methods for such kind of measurement is very important, since organic products have a special share in the international market, usually reaching much higher prices. Therefore, all efforts to identify characteristics that can differentiate conventio- nal and organic products are welcome to avoid fraud. This work aimed at the identification of chemical differences between conventionally and organically cultivated beans by applying instrumental neutron activation analysis. Experimental Samples of conventional and organic beans were collected from experimental fields in Batatais (Granja Shimura) and Campinas (Instituto Agronômico de Campinas – IAC), both cities located in the state of São Paulo, Brazil, and separated by a distance of about 250 km. In the organic cultivation, the experimental areas received 10,000 kg/ha of vermicompost fertilizer, while in the conventional cultivation it was used 400 kg/ha of synthetic fertilizer containing 4, 14 and 8% of N, P 2 O 5 and K 2 O, respectively. Four varieties were sampled in Granja Shimura (Table 1), i.e., Aporé, Diamante Negro, Jalo and Pérola, and five in the IAC field (Table 2), i.e., Aporé, Carioca, Diamante Negro, Jalo and Pérola.