Physicochemical and morphological properties of a small granule legume starch with atypical properties from wild mango (Cordyla africana L.) seeds : a comparison to maize, pea, and kidney bean starch

Abstract

The physicochemical properties of wild mango (Cordyla africana L) seed starch are assessed and compared to bean, pea, and commercial maize starch. Scanning electron microscopy (SEM) and polarized optical microscopy (POM) show that wild mango starch granules are truncated (cap‐shaped) have smooth surfaces, and are much smaller (5.7 μm) than bean (28.2 μm), pea (23.0 μm), and maize (11.1 μm) starch granules. Wild mango starch had a higher (p ≤ 0.05) gelatinization temperature (differential scanning calorimetry‐DSC, Tp = 77 °C), but a lower enthalpy (ΔH = 10.7 J g−1) than pea, bean, and maize starches. X‐ray diffraction (XRD) reveals a C‐type crystalline pattern, while Fourier transform infrared spectroscopy (FTIR) indicates that the starch has a higher degree of short‐range order compared to bean, pea, and maize starches. Rapid visco analysis (RVA) shows that its peak paste viscosity (2811 cP) is significantly (p ≤ 0.05) higher than that of bean, pea, and maize starch. Wild mango starch is similar (p > 0.05) to maize starch in terms of RVA granule‐breakdown and gelation‐related parameters, and gel texture (firmness = 114.7 N and strength = 339.4 ± 16.5 J), differed significantly (p ≤ 0.05) from bean and pea starch.