Pickering Emulsions Produced with Starch Nanocrystals from Cassava (Manihot esculenta Crantz), beans (Phaseolus vulgaris L.) and corn (Zea mays L.)

The objective of this study is to produce Pickering emulsions with starch nanocrystals from different starch sources. Bean starch is less susceptible to hydrolysis, followed by corn, and cassava starches. In both botanical sources the acid hydrolysis greatly reduce the amylose content in the nanoparticles. Oxidation increases the zeta potential of all the nanocrystals. In addition, the value of polydispersity decreases. A peak at 1,735 cm(-1) is detected by means of mid-infrared spectroscopy, which is characteristic of the free carboxyl group (acid form-COOH), expected on oxidized starches. Cassava and corn starches as well as their nanocrystals have an A-type crystallinity pattern. For bean starch, the original C-A-type crystallinity pattern remains for the non-oxidized nanocrystals but changes to A-type after oxidation. After hydrolysis, the relative crystallinity increases for nanocrystals, but decreases after oxidation. The exception is for bean starch that results in oxidized nanocrystals with higher relative crystallinity. In general, the oxidation of nanocrystals improves their emulsification index. The emulsification index is higher for the emulsions with larger amounts of oil, even though the average diameter of the droplets increases in this situation.