Fabrication and Characterization of Buforin I-Loaded Electrospun Chitosan/Polyethylene Oxide Nanofibrous Membranes with Antimicrobial Activity for Food Packing Applications

Abstract

The rising resistance of bacteria to antibiotics has driven the search for new antimicrobial agents. This study focused on encapsulating Buforin I, an antimicrobial peptide, in chitosan/polyethylene oxide (CS-PEO) nanofibers. Buforin I was loaded at a minimum bactericidal concentration (MBC), 10× MBC, and 20× MBC, with assessments on morphology, thermal properties, chemical bonds, crystalline structure, mechanical strength, antimicrobial activity, and cell toxicity. Techniques like differential scanning calorimetry and Fourier-transform infrared spectroscopy confirmed the effective loading of Buforin I in the nanofibers. Scanning electron microscopy showed that Buforin incorporation increased nanofiber diameters. The tensile strength peaked at 20× MBC. Microbial tests indicated that the inhibition zone for nanofibers at 20× MBC surpassed that of commercial antibiotics. Beef coated with CS-PEO nanofibers containing Buforin I demonstrated reduced pH and water activity, alongside lower weight loss during storage. Texture and color analyses revealed that the Buforin I nanofibers helped maintain beef hardness and slowed color degradation compared to control samples. Moreover, thiobarbituric acid levels and total microbial counts in the coated beef were significantly lower than controls (below 3 log CFU/g after 9 days at 4 °C). Thus, these nanofibers may serve as effective antimicrobial packaging agents to delay food spoilage.

Keywords: Buforin I; antimicrobial membrane; antimicrobial peptide; chitosan; electrospinning; shelf life extending.

Figure 1

Viscosity profiles for the solutions: (a) CS-PEO 2.5% and (b) CS-PEO 2.5% loaded with Buforin I at 20× MBC. The red curve represents viscosity as a function of shear rate, while the blue curve depicts shear stress as a function of shear rate.

Figure 2

SEM images and average diameters of nanofibers for (a) CS-PEO 2.5%, (b) CS-PEO 5%, (b) CS-PEO 2.5% loaded with Buforin I at MBC, (c) CS-PEO 2.5% loaded with Buforin I at 10× MBC, and (d) CS-PEO 2.5% loaded with Buforin I at 20× MBC.

Figure 3

FTIR spectra of nanofibers of (a) Buforin I, (b) CS-PEO 2.5%, (c) CS-PEO 2.5% loaded with Buforin I at MBC, (d) CS-PEO 2.5% loaded with Buforin I at 10× MBC, and (e) CS-PEO 2.5% loaded with Buforin I at 20× MBC.

Figure 4

Diffraction patterns of nanofibers of (a) Buforin I, (b) CS-PEO 2.5%, (c) CS-PEO 2.5% loaded with Buforin I at MBC, (d) CS-PEO 2.5% loaded with Buforin I at 10× MBC, and (e) CS-PEO 2.5% loaded with Buforin I at 20× MBC.

Figure 5

(a) Cumulative release of Buforin I; (b) cumulative release of Buforin I from CS-PEO nanofibers. PEO: poly ethylene oxide; BUF: Buforin I.

Figure 6

(a) Cell toxicity and (b) hemolytic activities of nanofibers of CS-PEO 2.5%, CS-PEO 2.5% loaded with Buforin I at MBC, CS-PEO 2.5% loaded with Buforin I at 10× MBC, and CS-PEO 2.5% loaded with Buforin I at 20× MBC on human fibroblast cell line. Different letters demonstrate significant differences (p < 0.05).

Figure 7

Evolution of the effects of electrospun Buforin I-loaded nanofibrous membranes on the texture profile included: (a) Hardness, (b) Springiness, (c) Cohesiveness, and (d) Thiobarbituric acid amount of beef samples during storage (4 °C). CS-PEO-BUF: coated with Buforin I-loaded CS-PEO nanofibers; CS-PEO: coated with CS-PEO nanofibers without Buforin I. Different lowercase letters indicate a significant difference (p < 0.05).