Physicochemical and structural properties of a bio-based antioxidant packaging film derived from Eremurus luteus root gum

Abstract

A novel bio-based film from Eremurus luteus root gum (ELRG), as a new source of glucomannans, was fabricated and the effects of two plasticizers (glycerol and sorbitol) and their concentration (30, 40, and 50% w/w) on some physical, optical, barrier, antioxidant and mechanical properties, and microstructure of the films were investigated. The results demonstrated that the increase in the plasticizers’ concentration from 30% to 50% (w/w) increased the moisture content, solubility, and water vapor permeability (WVP) but decreased the contact angle of the ELRG films. The maximum antioxidant activity of the films was obtained by the addition of 50% of glycerol or sorbitol. The plasticized films by different concentrations of glycerol exhibited more extensibility and lower tensile strength in comparison with sorbitol films. The color analysis revealed that increasing both plasticizers’ concentrations caused the L value to increase while the ΔE value decreased. The more transparency and light transmission were observed for the sorbitol films. The SEM images indicated smooth and uniform surface morphology without cracks of plasticized films compared with the unplasticized film. The results of the present study suggest that ELRG is a good source to fabricate bio-based films for the food products packaging or carrying bioactive components. • ELRG introduced as a new biomaterial source for an antioxidant film fabrication. • Influence of plasticizer type and concentration was investigated. • Physical, barrier, and mechanical properties, and microstructure were determined. • Glycerol indicated greater efficiency than sorbitol in plasticizing ELRG films. • The glycerol plasticized films showed more antioxidant activity.