Preparation and characterization of edible pullulan/pectin nanofiber substrates and their digestion in simulated gastric and intestinal fluids

This article utilizes two ingestible substrates, pullulan and pectin, to fabricate nanofiber membranes by means of electrospinning technology, and assessed their digestion characteristics in simulated gastrointestinal fluids. The physicochemical properties of pullulan/pectin spinning solution and the effects of electrospinning process parameters on the diameter and morphology of pullulan/pectin nanofibers were investigated. Scanning electron microscope indicates that the best electrospinning process parameters were obtained as spinning voltage: 20 kV, needle-collector distance: 15 cm, propulsion speed: 0.6 mL/h and needle inner diameter: 0.41 mm. Moreover, at a pullulan/pectin volume ratio of 8:2, the nanofiber morphology exhibited optimal characteristics, featuring an average fiber diameter of 369.45 +/- 42.41 nm. Fourier transform infrared spectroscopy, X-ray diffraction, and thermal analysis indicates the formation of strong hydrogen bonds between pullulan and pectin. The mechanical performance tests demonstrated that, with a volume ratio of 8:2 for pullulan and pectin, the nanofiber exhibited a tensile strength of 1196.86 +/- 51.87 cN and an elongation at break of 80.26 +/- 3.6%, indicating favorable capacity for elongation and deformation. Furthermore, the in vitro degradability test indicates that pullulan/ pectin nanofibers with a volume ratio of 8:2 were decomposed by specific enzymes in intestinal fluid. Therefore, ingestible pullulan/pectin nanofiber substrates have shown certain development potential in the field of targeted drug or bioactive delivery.