Cassava, corn, wheat, and sweet potato native starches: A promising biopolymer in the production of capsules by electrospraying

Native starches have a high potential for producing capsules by electrospraying despite still being little explored as biopolymeric material. Thus, the present study aimed to investigate the electrospraying capacity of native starches from different sources (cassava, corn, wheat, and sweet potato). The concentration of starch in the polymer solutions was varied from 3 % to 10 % (w/v) to investigate the impact of both starch source and concentration on the electrospraying process. The study also aimed to deepen scientific knowledge of the behavior of these starches during the process and the characteristics of the resulting capsules. The characterization of the polymeric solutions was carried out regarding rheology and electrical conductivity and the capsules were evaluated by production yield, morphology, size distribution, thermal properties, and crystallinity. Higher viscosities were observed for polymeric solutions obtained from sweet potato starch, compared to other starches at the same polymer concentrations. The increase in starch concentration in polymeric solutions reduced their electrical conductivity, except for corn starch. The production yield of cassava and sweet potato starch capsules was not affected by the polymer concentration in the polymeric solutions, while for corn and wheat starches, there was a reduction in yield as the concentration increased. All starches were able to form capsules. Capsules produced with 7 % corn starch showed a more homogeneous size distribution. The electrosprayed starches showed elevated melting temperatures and enthalpies. The capsules produced had an amorphous structure. The starches evaluated in this study proved to be excellent biopolymers for producing capsules by electrospraying, demonstrating possible future uses as encapsulating materials.