title: Characterisation of sweetpotato from Papua New Guinea and Australia: Physicochemical, pasting and gelatinisation properties.
abstract: The physicochemical and functional properties of flours from 25 Papua New Guinean and Australian sweetpotato cultivars were evaluated. The cultivars (white-, orange-, cream-, and purple-fleshed, and with dry matter, from 15 to 28g/100g), were obovate, oblong, elliptic, curved, irregular in shape, and essentially thin-cortexed (1-2mm). Flour yield was less than 90g/100g solids, while starch, protein, amylose, water absorption and solubility indices, as well as total sugars, varied significantly (p<0.05). Potassium, sodium, calcium, and phosphorus were the major minerals measured, and there were differences in the pasting properties, which showed four classes of shear-thinning and shear-thickening behaviours. Differential scanning calorimetry showed single-stage gelatinisation behaviour, with cultivar-dependent temperatures (61-84°C) and enthalpies (12-27J/g dry starch). Oval-, round- and angular-shaped granules were observed with a scanning electron microscope, while X-ray diffraction revealed an A-type diffraction pattern in the cultivars, with about 30% crystallinity. This study shows a wide range of sweetpotato properties, reported for the first time.
authors.affiliation: School of Land, Crop & Food Sciences, University of Queensland, St Lucia 4072, Australia.
authors.forename: Joel G
authors.initials: JG
authors.lastname: Waramboi
authors.affiliation: Queensland Department of Primary Industries & Fisheries, Gatton QLD 4343, Australia.
authors.forename: Sandra
authors.initials: S
authors.lastname: Dennien
authors.affiliation: Centre for Nutrition & Food Sciences, University of Queensland, St Lucia 4072, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gidley
authors.affiliation: School of Land, Crop & Food Sciences, University of Queensland, St Lucia 4072, Australia; Centre for Nutrition & Food Sciences, University of Queensland, St Lucia 4072, Australia. Electronic address: p.sopade@uq.edu.au.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Sopade
keywords: Crystallinity; Gelatinisation; Granule morphology; Minerals; Pasting; Physicochemical properties; Starch