A fast and efficient approach to prepare starch nanocrystals from normal corn starch

• Starch nanocrystals were prepared in less than an hour by the proposed method.
• The yield was comparable to other available methods with longer process time.
• Particle size of nanocrystals was lower than 100 nm.
• Crystallinity of nanocrystals preserved after applying proposed method.

In present study, simultaneous treatment of corn starch by ultrasound and sulphuric acid hydrolysis was investigated focussing a reduction in starch nanocrystal preparation time while increasing the yield. Different acid/starch concentrations, temperatures, and time durations were assessed through degree of hydrolysis, yield, particle size, and surface charge. It was observed that the method is capable of producing nanocrystals within 45 min with particle size smaller than 100 nm and up to 21.6% yield. The surface charge of nanocrystals was observed to be increased at elevated levels of independent parameters. Round edge nanocrystals with diameters smaller than 50 nm were observed under TEM. The results revealed that sonication during nanocrystal preparation not only preserved the crystalline structure, but also reasonably increased the efficiency of hydrolysis to produce starch nanocrystals. The results of the present study would be of great importance to adopt large scale production of nanocrystals from starch.

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