Abstract
Starch nanocrystal was prepared using weak sulfuric acid hydrolysis at 40 °C. Transmission electron micrographs of dilute suspensions of starch nanocrystals showed round particles with a diameter ranging from 20 to 40 nm. SEM of freeze dried samples showed separated particles between 40 and 100 nm and confirmed production of starch nano particles. XRD patterns obtained for the prepared nanostarch and raw starch sample showed no special pattern of crystallinity for starch sample. Extracted nanostarch showed pattern of crystallinity with the peaks at Bragg angles (2θ) at about 15° and 23°, and a doublet at 17° and 18°. The crystalline structure of prepared sample was A-type. FTIR spectra confirmed the particles oxidation. Nano silver particle was precipitated on the starch nano particle. UV spectra confirmed the presence of silver particle on the starch particles. Inhibitions tests of nanostarch bearing nano silver on three types of bacteria was investigated. The inhibition test results were 25 µg/mL for S. aureus, and S. typhi, and 12.5 µg/mL for E. coli.