Effect Of irradiation on anti-nutrients (total phenolics, tannins and phytate) in Brazilian beans

The Brazilian bean varieties Phaseolus vulgar-is L. var. Carioca and Vigna unguiculata (L.) Walp var. Macacar were irradiated with doses of 0.5, 1.0, 2.5, 5.0 and 10 kGy and subsequently stored at ambient temperature for 6 mo nths. The anti-nutrients phenolic compounds, tannins and phytate were deter mined to be 0.48 mg g(-1) dry basis, 1.8 mg g(-1) dry basis and 13.5 mu mol g(-1) dry basis in the raw non-irradiated Carioca beans and 0.30 mg g(-1) dry basis, 0.42 mg g(-1) dry basis and 7.5 mu mol g(-1) dry basis in the ra w non-irradiated Macacar beans. After soaking and cooking a higher content of phenolic compounds and a lower phytate content was observed in both bean varieties. Tannin content was not affected by soaking and cooking of Cario ca beans, but higher after soaking and cooking of Macacar beans. Using radi ation doses relevant for food did not effect the content of the anti-nutrie nts under investigation in both bran varieties. (C) 2000 Elsevier Science L td. All rights reserved.