Abstract:

A method using high-performance size-exclusion chromatography (HPSEC) equipped with multi-angle laser-light scattering (MALLS) and refractive index detector (RID) was presented for determining molecular features of starch. Results indicated that the weight-average molecular weight (Mw), z-average radius of gyration (rz) and polydispersity index could be obtained using the Berry extrapolation method with a third-order polynomial fitting. The Mw (rz) of common maize starch, waxy maize starch, wheat starch, sticky rice starch, rice starch and potato starch were measured to be 17.94 × 107 g/mol (79 nm), 18.11 × 107 g/mol (81.1 nm), 7.86 × 107 g/mol (50.4 nm), 13.04 × 107 g/mol (62.9 nm), 64.3 × 107 g/mol (64.3 nm), and 7.73×107 g/mol (75.9 nm), respectively. This method can provide a convenient and easy approach for starch molecule structure analysis.

Key words: starch structure, weight-average molar mass, z-average radius of gyration, Berry method