Characterization of biodegradable films based on guar gum and calcium caseinate incorporated with clary sage oil: Rheological, physicochemical, antioxidant, and antimicrobial properties

Clary sage essential oil (CSEO) has been reported for its wide food and pharmaceutical applications. This work aimed to produce biodegradable active guar gum-calcium caseinate (GG-CC) based film incorporated with CSEO and to evaluate its physico-chemical, antioxidant, and antibacterial properties. Solvent casting technique was used to prepare the composite films containing CSEO at 0.1, 0.15, and 0.2% (v/v). The chemical, rheological, morphology, mechanical, thermal, optical, crystalline, biodegradable, water barrier, antioxidant and antimicrobial potential of the samples were assessed by various analytical methods. Rheological findings of filmogenic solution revealed that the viscosity of filmogenic solutions (GCEO2-GCEO4) increased with an increase in the concentration of the CSEO. CSEO addition in GG-CC film exhibited a homogenous structure with low crystallinity, transparency, water vapor permeability, moisture content, and tensile strength values, whereas a rise in elongation at break, thickness, and thermal stability was observed. Fourier transforms infrared (FTIR) results suggested the interaction between CSEO and GG-CC-CSEO films also exhibited satisfactory antioxidant activity against DPPH and ABTS free radicals and higher antimicrobial effect against the Gram-negative bacteria (Pseudomonas aeruginosa). This work revealed that CSEO has the potential to be used as an active ingredient in the development of films for food packaging applications.