Identification of starch with assorted shapes derived from the fleshy root tuber of Phoenix sylvestris : extraction, morphological and techno-functional characterization

Currently, the starch of edible tubers from underutilized plants has been receiving considerable attention among starch manufacturers for versatile applications because of the abundance, cost-effectiveness, and biodegradability. The present study reports the isolation of a white-coloured crystalline starch of high purity (96.18 g 100 g −1 ) from the fleshy root tuber of wild palm, Phoenix sylvestris , through water treatment and its characterization by different analytical techniques, such as Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy (XRD), differential scanning calorimetry (DSC), Scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The physicochemical analyses revealed the amylose content of the starch to be 62.39 g 100 g −1 . Through XRD probing the crystallinity and nature of starch were determined to be 22.12 ± 0.21% and B-type, respectively. The SEM analysis detected the assorted shapes of starch with a granular size in the range of 1–10 µm. The formation of unique flowery-shaped starch granules due to the complexation with protein through noncovalent interaction was also evident from the SEM image. From the DSC and TGA studies, the gelatinization parameters such as the onset (T 0 ), peak (T p ), complete gelatinization (T c ) temperatures, and enthalpy for the starch isolate were determined as 68.19 ± 0.02 °C, 82.27 ± 1.12 °C, 95.03 ± 0.15 °C, and 11.29 ± 0.01 J g −1 , respectively. The increase in enthalpy value of the retrogradation process on longer storage times demonstrated the higher reorganization of starch components. The characteristic temperatures of the retrogradation process were lower than the corresponding gelatinization process temperature. The scavenging of DPPH and ABTS radicals by the candidate starch confirmed its antioxidant properties. The overall studies indicated that the isolated novel starch could ascertain the applications in the production of biodegradable films for food packaging, preparation of syrups with high glucose content, as well as its incorporation into cooked and canned products.