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

• Published in: Starch - Stärke 2018-11, Vol.70 (11-12), p.n/a
• Main Authors: Ngobese, Nomali Ziphorah, Wokadala, Obiro Cuthbert, Plessis, Belinda Du, Da Silva, Laura Suzanne, Hall, Alan, Lepule, Sello Presly, Penter, Mark, Ngcobo, Mduduzi Elijah Khulekani, Swart, Hendrik C.
• Format: Article
• Language: English
• Subjects: Calorimetry; Cordyla; Corn; Differential scanning calorimetry; Diffraction patterns; Enthalpy; Firmness; Fourier transforms; gel textures; gelatinization; Gelation; Granular materials; Infrared spectroscopy; Kidney beans; legume starches; Mangoes; Microscopy; Optical microscopy; Physicochemical properties; Properties (attributes); Rapid Visco‐Analysis (RVA); Scanning electron microscopy; Seeds; Starch; Starches; Viscosity; X ray spectra; X-ray diffraction
• ISSN: 0038-9056; 1521-379X
• DOI: 10.1002/star.201700345

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. Wild mango seed starch granules are much smaller than other legume starch granules and resemble cassava, tannia and jackfruit granules in shape. This starch has a higher gelatinization temperature and peak paste viscosity compared to bean, pea and maize starch. It results in a cold gel (as pictured) texture that is more similar to maize than legume starches.