Development of antimicrobial coatings: exploiting electrospinning technology with sugar beet pulp pectin

Pectin derived from sugar beet co-products was utilized to formulate electrospun fibers, reinforced with the microbial exopolysaccharide pullulan. Different pectin:pullulan ratios were evaluated (10:0, 9:1, 8:2 and 7:3), targeting the formulation of uniform pectin-based fibers. The incorporation of different surfactant concentrations (1 %, 2 % and 5 % w/w) was also evaluated. The optimal fibers were used as a matrix to encapsulate the antifungal agent natamycin, targeting active fibers formulation. The mean diameter of the pectin:pullulan fibers was 101.7 nm, whereas natamycin addition increased the diameter up to 128.2 nm. The highest encapsulation efficiency was 92.3 %, following a declining trend as the natamycin concentration increased. Fourier transform infrared spectroscopy analysis indicated that the biopolymers interacted through hydrogen bonds, whereas Raman spectroscopy showed natamycin distribution across the entire width of the fibers. Natamycin incorporation into the pectin-based fibers at low concentrations enhanced the polymer network via hydrogen bonds formulation and hydrophobic interactions, leading to similar or increased hydrophobicity and mechanical properties. The water contact angle, Young's modulus and surface adhesion values of the selected fibers were 35.91ᵒ, 719.5 MPa and 19.6 nN, respectively. Finally, the fibers possessed antimicrobial activity against Aspergillus niger, which indicates their applicability as active coating on food packaging materials.