Structure Elucidation of Soluble Dietary Fiber from Cauliflower Nilufar Nahar*, A K M Ahsan Habib, S M Mizanur Rahman and Tofail Ahmed Chowdhury

Abstract

Arabinogalactan and rhamnogalactglucuronan were isolated from soluble dietary fiber (SDF) of cauliflower. The
isolated SDF was fractioned into neutral and acidic parts by ion-exchange column chromatography using DEAESepharose
Cl-6B gel. Structure elucidation of the isolated SDF polysaccharides were determined sugar analysis, 1HNMR,
H-H COSY and TOCSY spectroscopic studies. Neutral fraction of cauliflower was found to be composed of
galactose, arabinose and rhamnose whereas the acidic part was found to contain rhamnose, galactose, galacturonic
and glucuronic acids. The main chain of the neutral fraction was found to be a 1,4-β-galactan where terminal
rhamnose and arabinose residues were attached to the main chain at the 3-position of by α-linkage.The main chain of
the acidic fraction was composed of 1,4-b-linked galacturonic acid and 1,2-b-linked rhamnopyranos