Effect of ultraviolet-irradiation on the physicochemical and disintegrability properties of nanocomposite tunta starch:tara gum films reinforced with starch nanocrystals

Abstract

ABSTRACT Biodegradable films based on a blend of Peruvian tunta starch (TS) and tara gum (TG) (95:5) reinforced with TS nanocrystals (NC) were prepared using the casting method. The effect of ultraviolet (UV)-irradiation time (60 and 120 min) and the NC concentration (0, 5, and 10 g/100 g biopolymers) on the physicochemical and disintegrability properties of nanocomposite TS:TG films were investigated. Tensile strength and Young’s modulus were increased from 4 to 14 MPa and 14 to 600 MPa, respectively; meanwhile, the elongation was reduced by about 90% by increasing NC amount, mainly at lower UV-time. The color parameters and the UV–vis light barrier showed a significant (p < .05) variation mainly due to the NC effect. The higher the NC content, the lower the moisture barrier (p < .05). Neither NC nor UV time significantly impacted the moisture content, water solubility, crystallinity, or chemical composition. SEM micrographs showed a roughness increase in the films’ microstructure with a marked difference among treatments. All films were disintegrated more than 80% after 5 days of burying under composting conditions. The UV-irradiation combined with TS nanocrystal reinforcement caused a significant enhancement of some TS:TG films’ properties, suggesting their possible use as eco-friendly packaging.