Effect of amylose content on the preparation for carboxymethyl starch/pullulan electrospun nanofibers and their properties as encapsulants of thymol

We proposed a green approach for the preparation of Carboxymethyl starches (CM-starches)/pullulan (PUL) nanofibers and explored their potential properties as encapsulates of thymol. CM-starches from high-amylose (CM-HAS), normal (CM-NCS), and high-amylopectin corn starch (CM-WCS) were synthesized and studied for their spinnability, yet non-fibers could be obtained from these CM-starches. The 20% of PUL was further used to obtain the series of CM-starches/PUL nanofibers from varying CM-starches concentrations. Amylose molecule with efficient molecular entanglement as well as its good solution properties was proved to enhance the elec-trospinning process with the PUL. Furthermore, the pre-complex of CM-starches-thymol was incorporated in PUL nanofibers using the electrospinning technique. The thymol was successfully encapsulated in nanofibers with a bead-like and increased diameter compared to the morphology of nanofibers without thymol. The pre-complex of CM-HAS-thymol provided a high encapsulation efficiency (EE, 96.59%) for thymol in PUL nanofibers. The in-clusion complexation also provided enhancement of thermal stability for thymol and PUL nanofibers. Therefore, the designed nanofibers with thermal stability, degradability, and antibacterial properties have the capacity to be used in food applications.

Automated summary

This study proposed a green approach to prepare CM-starches/PUL nanofibers as encapsulates of thymol. The CM-starches from different corn starches were synthesized and studied, and PUL was used to obtain the CM-starches/PUL nanofibers. The electrospinning technique was used to encapsulate the CM-starches-thymol complex in the PUL nanofibers, resulting in nanofibers with increased diameter and improved thermal stability and encapsulation efficiency for thymol.