Structural and physicochemical characterization of porous starch prepared by enzymatic hydrolysis, solvent‐exchange, and freeze–thaw cross‐linking treatments

Summary Porous starches have been researched for applications of its characteristics, although it has been noted that different methods are used to influence the properties manifested. In this study, native starch isolated from hyacinth bean ( Lablab purpureus ) was used to create porous starch using three different methods, viz, solvent‐exchange (SE), enzyme hydrolysis (EH), and addition of mercaptosuccinic acid known as freeze–thaw (FT). The structural characteristics (Fourier‐transform infrared spectroscopy, X‐Ray Diffraction) of SE and EH were very similar to those of NS. The gelatinization properties of the porous starches were higher (97.15–112.86) than those of NS (93.00–103.69). The pasting properties of SE and EH were improved, while FT did not possess any pasting abilities, this was due to its high solubility (42.92 ± 1.70) and lipophilic nature (4.63 ± 0.42). The adsorption properties of SE (4.0616.35) and EH (4.31–15.45) were similar to those of NS (3.53–15.50). The swelling power of SE (9.16 ± 0.19) and EH (9.25 ± 0.13) was similar to that of NS (9.76 ± 0.43), while the amylose contents (15.48–19.43) were lower than those of NS (20.68 ± 4.39). Only the SE (11.42 ± 3.40) from the porous starches had resistant starch present, while EH had mostly rapidly digestible (13.23 ± 0.00) and slowly digestible starch (127.16 ± 0.00). These structural and physicochemical characteristics show that these porous starches may be suitable in delivery systems, improving solubility of drugs and adsorbing dyes.