Uptake of Polycyclic Aromatic Hydrocarbons by Insoluble Dietary Fiber

Abstract

The sorption isotherms of polycyclic aromatic hydrocarbons (PAHs) by insoluble dietary fiber (IDF) were measured in artificial gastric juice (AGJ) and artificial intestinal juice (AIJ) at 37◦C and then the sorption behavior of IDF was examined. Benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[a]pyrene were used. It was suggested that the uptake of PAHs by carboxymethyle cellulose (CMC), agar, and IDF from powdered young barley leaves (YBL) involved not single sorption behavior, but complex sorption behavior. YBL had an extraordinarily high sorption capacity (60.7–147.3 nmol/g in AGJ and 76.7–162.7 nmol/g in AIJ), as compared with CMC (1.5–3.6 nmol/g in AGJ and 1.1–2.7 nmol/g in AIJ) and agar (0.1–0.4 nmol/g in AGJ and 0.3–0.7 nmol/g in AIJ) at a residual concentration of 5.0 nM. The sorption of PAHs in AGJ and the desorption of PAHs from IDF in both AGJ and AIJ indicate that the sorbed PAH molecules are held firmly by IDF while it passes through the digestive tract in vivo. From the results on sorption capacity and the removability of PAHs from IDF, YBL would be expected to be more useful than CMC and agar.