Development of starch nanoparticles based composite films from non-conventional source - Water chestnut (Trapa bispinosa)

In the present study, starch was isolated from a non-conventional source (water chestnut) and various physicochemical properties were investigated. Nano starch was prepared by adopting the acid hydrolysis method having a yield of 27.5%. Particle size distribution of native and nano starch was 5559 nm and 396 nm. The unique feature of water chestnut starch was the shape of starch granule that looked oval, ellipsoidal, mixed with spherical granules without cracks and smooth surface. While the water chestnut nano starch appeared as an agglomerated form with irregular and rough surface. Water chestnut starch nanocomposites films with varying concentrations of starch nanoparticles (SNPs) were synthesized by a solution casting method. The thickness, moisture content, water vapour transmission rate, water solubility, burst strength of native starch and nano starch composite films were evaluated. The results showed that native starch film had thickness (0.041 ± 0.07 mm) moisture content (4.17 ± 0.32%), water vapour transmission rate (4.678 × 10-3 ± 0.42 g-2 s-1), water solubility (35.71 ± 0.17%) and burst strength (976.4 ± 12.47 g), respectively. The incorporation of SNPs results in an increase in thickness and burst strength while moisture content, water vapour transmission rate and solubility of films were decreased with the increase in the concentration of SNPs which is essential features of a good package.