Simple ultrasound method to obtain starch micro-and nanoparticles from cassava, corn and yam starches

Starch nanoparticles (SNP) were produced employing a simple ultrasound method without chemical additives from cassava, corn, and yam starches, which contain 18%, 25% and 30% amylose, respectively. Simultaneously, starch microparticles (SMP) were also obtained, which were significantly smaller than the native starch granules. The yield of the process for all starch sources was 12 +/- 1% SNP and 88 +/- 5% SMP, starting with aqueous starch suspensions at 10% and 30 min of sonication. Yam starch (higher amylose content) resulted in smaller SMP (1-3 mu m) and SNP (8-32 nm) than did those obtained from corn (SMP = 3-6 mu m; SNP = 36-68 nm) and cassava (SMP = 3-7 mu m; SNP = 35-65 nm) starches. Nanoparticles from all starch sources had lower crystallinity and lower thermal stability than did the native starches or SMP. Ultrasonication was efficient to yield SNP and SMP without the addition of any chemical reagent or employing a purification step.