The polysaccharide composition of yellow passion fruit rind cell wall: chemical and macromolecular features of extracted pectins and hemicellulosic polysaccharides

BACKGROUND: Yellow passion fruit (Passiflora edulis var. flavicarpa Degener) is one of the main sources of juice production in tropical regions, the extraction of which generates large amounts of rind and seeds as by-products. In a view to valorize rinds as a possible fiber source, the whole polysaccharide composition is first investigated. RESULTS: Cell wall material, from rinds, consists of similar to 80% (w/w) non-starchy polysaccharides, of which 42% is cellulose, 25% pectic substances and 12% hemicelluloses. Fractional extraction of non-starchy polysaccharides from cell wall material showed that the degree of methyl esterification, intrinsic viscosity and weight-average molecular mass of extracted pectins range widely from 5 to 40, from 170 to 580 mL g(-1) and from 58 000 to 105 000 g mol(-1), respectively. Likewise, the intrinsic viscosity and weight-average molecular mass of extracted hemicellulosic polysaccharides range from 40 to 55 mL g(-1) and from 21000 to 48 000 g mol(-1), respectively. Chromatographic fractionation of hemicellulosic fractions and glycosyl linkage analysis substantiate the presence of similar to 90% (w/w) of xyloglucans and 10% (w/w) of glucomannans of the whole fraction. CONCLUSION: The cell wall material, obtained from yellow passion fruit rinds, contains high amounts of non-starchy polysaccharides. Cellulose appears to be the predominant polysaccharide, thus denoting a potential insoluble fiber source. (C) 2008 Society of Chemical Industry.