Development of zein nanofibers for the controlled delivery of essential amino acids for fish nutrition

Abstract

In the present paper, films and nanofibers of zein and zein/tryptophan were produced by casting and eletrospinning. The films and nanofibers were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and controlled release and digestibility tests. In vitro releasing of tryptophan was evaluated using a spectrophotometer UV-Vis. Interactions between tryptophan and zein were confirmed by thermal (TGA) and spectral (FTIR) analyses. SEM micrographs provided evidence of a smooth and homogeneous structure for films and nanofibers without and with tryptophan. FTIR spectroscopy indicated seconddegree intermolecular interactions between amide groups of zein and tryptophan. X-ray analysis indicated the formation of crystals that did not interfere with the crystallization of amino acid. By in vitro release experiments, it was possible to observe that the tryptophan releasing follows nearly Korsmeyer-Peppas model for the nanofibers and Peppas-Sahlin model for films, indicating the releasing process of the nanofibers are by diffusion of the amino acid and, for films, by relaxion of polymeric chain. Finally, in vitro digestibility a considerable amount of tryptophan was observed, suggesting more access of fishes for tryptophan.

Zein/MnO2 Nanosheet Composites Integrated with a Smartphone for Colorimetric Sensors for On-Site Detection of Adulterants in Milk

“…TGA (Figure S3) was employed to examine the material composition in relation to the proportion of each constituent. Pure zein exhibited two weight losses, where the first occurred below 100 °C and was attributed to the removal of physically adsorbed water. , The second loss is associated with the decomposition of the main protein structure of zein, resulting from the breakage of low-energy intermolecular bonds. , The overall residue accounted for 14% of the total. The MnO 2 NSs displayed two distinct stages of mass loss.…”

“…Pure zein exhibited two weight losses, where the first occurred below 100 °C and was attributed to the removal of physically adsorbed water. 44,45 The second loss is associated with the decomposition of the main protein structure of zein, resulting from the breakage of low-energy intermolecular bonds. 44,45 The overall residue accounted for 14% of the total.…”

“…44,45 The second loss is associated with the decomposition of the main protein structure of zein, resulting from the breakage of low-energy intermolecular bonds. 44,45 The overall residue accounted for 14% of the total. The MnO 2 NSs displayed two distinct stages of mass loss.…”

Improvement in the Sustained-Release Performance of Electrospun Zein Nanofibers via Crosslinking Using Glutaraldehyde Vapors

“…Furthermore, zein has shown low digestibility and controlled release capability [43,44]; thus, its nanofibers have drawn great interest in the controlled delivery of bioactive compounds. Silva et al (2020) indicated a lower release rate of tryptophan from zein nanofibers compared with that from zein films [45]. In the study by Defrates et al (2021), a more sustained release of model drugs (rifampin, rhodamine B, and crystal violet) was observed in zein fibers compared with zein films [46].…”