Binding capacity of various fibre to pesticide residues under simulated gastrointestinal conditions

The purpose of this study was to compare the effect of the nature and quant ity of various dietary fibre (cellulose, hemicellulose, pectin, lignin:) in diets on the binding capacity to pesticides-azin-phos-methyl (AZM), chlorp ropham (CLP), chlorothaionil (CKL), permethrin (PER) as estimated by solubi lity under conditions of pH and temperature simulating those in the gastroi ntestinal tract (incubated at pH 2 for 30 min at 37 degrees C, then at pH 7 for 60 min). The ratios of fibre to pesticides were determined in omnivoro us diets. Tn this model, the binding capacity of lignin was equal to hemice llulose for PER, AZM and CLP, but it was significantly higher for CKL. Hemi cellulose bound more CKL, AZM and CLP than did cellulose. Although pectin a ppreciably decreased all pesticides, its effect was lower than other fibres with one exception-cellulose-CKL. In the presence of equal amounts of fibr e, lignin exerted the most significant effect on pesticide solubility. Hemi cellulose and cellulose bind to the same extent PER and AZM. The effect of pectin was significant only on CKL and AZM when compared to the control. (C ) 2000 Elsevier Science Ltd. All rights reserved.