Physicochemical and microbiological evaluation of acidmodified native starch derived from Borassus aethiopum (Arecaceae) shoot

Abstract

Purpose: To evaluate the physicochemical properties and microbiological quality of Borassus aethiopum shoot acid-modified starch (AMS) for potential pharmaceutical applications.
Methods: Modification of Borassus aethiopum native starch (NS) was carried out using 6 % w/v HCl at 37 ± 2 oC for 192 h. The AMS was characterised for their morphological, micromeritics, rheological, thermal properties as well as their microbiological quality using standard protocols.
Results: AMS demonstrated increased aqueous solubility, crystallinity and slight increase in flow properties. There was a reduction in swelling and hydration capacities, amylose content as well as viscosity of the modified starch. Scanning electron microscopy analysis showed that the integrity of the modified starch granules were maintained and there was no disruption of the granular structure. Fourier transform infrared spectrophometer data confirmed the hydrolysis of NS with the increase in the intensity of the O-H stretch. AMS met United States Pharmacopoeia requirements in terms of microbiological quality, however, there was presence of Aspergillus niger.
Conclusion: Modification of Borassus aethiopum shoot starch by acid treatment led to desirable improvement in some of its physicochemical properties which could improve its functional properties in pharmaceutical industries.

Keywords: Native starch, Acid-modified starch, Borassus aethiopum, Microbiological quality, Physicochemical properties