Isolation and partial characterisation of native starches of new banana and plantain hybrids (Musa spp.) in comparison with that of plantain variety Orishele

Native starches were extracted from four new banana hybrids (CRBP 14, CRBP 39, FHIA 17 and FHIA 21) and from Orishele, a plantain variety (Musa sop) used as control. Purity (determined by the polarimetric method), iodine complex absorption spectrum (conducted according to Garcia and Lajolo), size and shape of granules (determined with a scanning electron microscope and an optical microscope equipped with a micrometer), swelling power and solubilization patterns (determined according to Leach et al.) were the characteristics under study. For the four banana hybrids, starch purities range from 96.55 to 97.83%, whereas it stands at a medium value in the case of the control (Orishele variety). The absorption maxima of the starch-iodine complexes for the five cultivars occurred between 620 and 630 nm, with absorption averages ranging between 1.11 and 1.85%. Again, the control variety Orishele has medium value for iodine absorption. The majority of starch granules is of oblong shape, and their lengths range from 3.33 to 56.66 mu m. CRBP 14 and CRBP 39 have the largest granule sizes, followed by Orishele; hybrids FHIA 21 and FHIA 17 having the smallest sizes. At high temperatures hybrid FHIA 17 shows the lowest increase of swelling and solubilisation. This hybrid also presents the lowest setback, swelling and solubilisation values. This hybrid also has the smallest starch granule sizes together with the lowest iodine absorption. Apart from starch setback, the other three hybrids (CRBP 14, CRBP 39 and FHIA 21) show characteristics that are superior to those of the control. Hybrid FHIA 17 can be classified as of sweet banana type, whereas the three other hybrids are of plantain type.