Método de digestão parcial de feijão cru (Phaseolus vulgaris) por hidrólise ácida para a determinação simultânea de nutrientes inorgânicos por ICP OES: validação e aplicação A partial digestion method of raw bean (Phaseolus vulgaris) by acid hydrolysis for simultaneously determining inorganic nutrients by means of ICP OES: validation and application

In this investigation a wet digestion technique (HCl hydrolysis) of raw bean (Phaseolus vulgaris) was validated in order to perform the simultaneous determination of inorganic nutrients Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn by means of inductively coupled argon plasma optical emission spectrometry (ICP OES). This simple, relatively rapid, and with satisfactory performance characteristics technique was employed for analyzing 40 raw bean marketed in Sao Paulo state (Brazil). After determining inorganic nutrients by emission spectrometry, the obtained concentrations of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn contents (in mg/100g bean) were 120±20; 0.8±0.1; 6.0±0.9; 1370±80; 170±10; 1.5±0.4; 1.4±0.4; 350±50; and 2.6±0.3, respectively. These inorganic nutrients contents are in agreement with the information from six food composition tables, except of Na that showed a significantly lower value. The results were also used to estimate the bean consumption contribution in Recommended Daily Intakes (RDI) for the investigated nutrients, and it was noted that bean can significantly contribute in Cu, Mg, Mn, P, Fe, and Zn RDIs.