Effect of traditional, microwave and industrial cooking on inositol phosphate content in beans, chickpeas and lentils.

An high-performance liquid chromatography method for determining inositol phosphate fractions was adapted to legumes. The validity of the method was assessed by estimating the following analytical parameters: linearity (linear response between 125 and 5000 microg inositol hexaphosphate (IP(6))/ml); instrumental precision and method precision (relative standard deviation, %) were 1.9% (IP(6)) for instrumental, and 2.5% (IP(6)) and 8.2% (IP(5)) for method precision. An accuracy was estimated by percentage recovery (72 +/- 3%). The application of this method to raw, conventional, microwave-cooked and ready-to-eat beans, chickpeas and lentils gave IP(6) contents ranging from 0.63 g/100 g dry matter in ready-to-eat lentils to 1.87 g/100 g dry matter in raw beans. The IP(6) content was reduced by all the cooking procedures, while the relative percentage of inositol pentaphosphate increased in all the legumes studied, and reached the maximum of 31% (expressed in relation to dry matter) in ready-to-eat beans.