Engineering Furcellaran/Xanthan Gum/Beeswax Composite Films Containing Spirulina via High-Shear Homogenisation: Structural and Physicochemical Properties

The growing demand for sustainable and functional packaging has driven the development of biopolymer-based films prepared from food-grade components with potential suitability for edible packaging applications. This study focused on the development and characterisation of furcellaran/xanthan gum/beeswax composite films enriched with Spirulina biomass and prepared using high-shear homogenisation (HSH). The effect of Spirulina incorporation on the structural, physicochemical, mechanical and morphological properties of the films was evaluated. HSH enabled the dispersion of beeswax and Spirulina within the polysaccharide-based matrix. The FTIR spectra showed absorption bands consistent with polysaccharide-associated vibrations, including 3,6-anhydrogalactose (~930 cm−1) and galactose-4-sulfate (~845 cm−1), and indicated changes in selected functional group regions after Spirulina incorporation. XRD revealed ordered beeswax-related domains, including a reflection corresponding to a d-spacing of about 15.27 Å. Spirulina decreased the contact angle, increased WVTR approximately 2.5-fold and reduced the maximum breaking load, whereas tensile strength and elongation at break remained comparable between formulations. SEM showed a more heterogeneous morphology in Spirulina-containing films, with pores, voids and local biomass clusters. The films exhibited approximately 59% (FUR/XAN/BE) and 47% (FUR/XAN/BE/S) water solubility but formed turbid hydrogels during extraction, preventing reliable direct ABTS and CUPRAC determination. The results indicate potential for edible coatings, although further optimisation and validation are required.