**4. Conclusions**

Polyphenolic content and antioxidant activity studies have demonstrated açaí to be the fruit with the highest content of active compounds. Studies of electrospinning encapsulation for the development of zein capsules containing hydroalcoholic açaí extract have also indicated the protective effect of these protein structures. This fact was certainly due to the positive chemical interactions observed through infrared spectroscopy between protein and active compounds from açaí extract. Zein was confirmed to be an adequate protein for the encapsulation of thermal sensitive active compounds by improving the thermal stability of polyphenols from açaí fruit when exposed to high-temperature treatments related to processed foods. After in vitro digestion processes, açaí polyphenols were also protected and diffused thanks to the breakage of zein protein electrosprayed capsules.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2076-3921/8/10/464/s1, Figure S1: Optical microscope images of electrosprayed samples.

**Author Contributions:** C.L.d.D. designed and supervised the research. L.G. optimized the conditions of zein solution and electrospinning equipment. C.P. executed experimental part related to characterization measurements and analysis of results. M.J.G. guided the execution of this work and C.A. carried out bioaccessibility studies. All the authors collaborated with the writing.

**Acknowledgments:** This work was supported by CONICYT through the Project Fondecyt Regular 1170624 and "Programa de Financiamiento Basal para Centros Científicos y Tecnológicos de Excelencia" (Project FB0807).

**Conflicts of Interest:** The authors declare no conflict of interest.
