Comparative study of physicochemical properties of breadfruit (Artocarpus altilis) and white yam starches

Starch from seedless breadfruit (Artocarpus altilis) was isolated and its granule characteristics, structural, physicochemical and rheological properties compared with white yam starch. Both starches exhibited a B-type diffraction patterns with a crystallinity of 36.2% for breadfruit starch and 37.3% for white yam. The two starches differed in granule size distribution and morphology; while breadfruit starch consisted of small, irregular shaped and aggregated granules (2.3-8.4 μm), white yam starch granules were large (19.2-30.8 μm), smooth and uniformly polyhedral. The amylose content and peak gelatinization temperature were different for breadfruit starch (20.0%; 69.3 °C) and white yam starch (22. 8%; 70.2 °C). The gelatinization temperature increased while the enthalpy decreased with increase in sodium chloride concentration for both starches. The starch molecules of breadfruit have a lower weight average Mw (1.72 × 107 g/mol) compared with white yam starch (Mw = 2.32 × 107 g/mol). The swelling power (SP), amylose leaching (AML) at 95 °C, and paste clarity (PC) at 1% (w/w) of breadfruit starch (SP, 39.4 g/g; AML, 5.23%; PC, 2.25%) were lower than those of white yam starch (SP, 49.8 g/g; AML, 10.9%; PC, 12.79%). Its shear viscosity was lower but its ability to withstand viscosity breakdown was higher than white yam starch. The properties of breadfruit starch indicate it would require modification to improve water binding capacity and clarity of the paste, and reduce retrogradation. However, the small granule size of breadfruit starch makes it a candidate for application as a dusting starch. © 2011 Elsevier Ltd. All rights reserved.