Physicochemical characterization of wheat bran and Kappaphycus alvarezii dietary fibres and their ability to bind mutagens, PhIP, Trp-P-2, AαC and BαP

The physicochemical properties of wheat bran and Kappaphycus alvarezii, and their binding ability to heterocyclic amines and polycyclic aromatic hydrocarbons such as, PhIP, Trp-P-2, AC and B alpha P, were investigated. High swelling capacity (14.9 mL/g) and water retention capacity (10.4 g/g) observed in K. alvarezii could be attributed to the high amounts of soluble fraction (68%). Galactose dominated in K. alvarezii dietary fibre, having alternating units of D-galactose-4-sulphate and 3,6-anhydro-D-galactose. Wheat bran consisted of glucose, xylose and arabinose, which formed cellulose and hemicelluloses. Presence of sulphur is another distinct property of K. alvarezii. Insoluble and soluble fractions of K. alvarezii dietary fibre showed superior binding ability than wheat bran. Hydrophobic mutagens were more effectively adsorbed to the dietary fibres. Molecular dynamics simulation indicated that the interaction energy between B alpha P and both the dietary fibres were lowest, possibly indicating a strong interaction between the planar rings of B alpha P and the fibre. The molecular dynamics results indicated high interaction energy for mutagens with marine fibre that were in accordance with the experimental results. (C) 2015 Elsevier Ltd. All rights reserved.