Application of Psyllium Gum in Sustainable Packaging: A Comprehensive Review

As a sustainable alternative to petroleum-based plastics, psyllium gum, a natural hydrocolloid from Plantago ovata seeds, is reviewed for its application in packaging. This review focuses on the material properties of psyllium gum, including its film-forming capacity, water-binding capacity of 12–15 g/g, and rheological behavior (consistency index K = 10–50 Pa·sn, flow behavior index n = 0.3–0.6), which are critical for packaging applications. We discuss how its performance can be enhanced through interactions with plasticizers, cross-linking agents, and blending with other biopolymers (e.g., polyvinyl alcohol and starch), as well as through nanocomposite reinforcement, to improve mechanical strength (tensile strength 5–15 MPa in native films; up to 48 MPa in thermoplastic starch composites), and barrier properties (e.g., oxygen permeability < 0.001 g/m2 s). The review also provides a comparative analysis of psyllium-based films with other polysaccharide films and discusses the environmental benefits, such as a lower carbon footprint (GWP ≈ 1.2 kg CO2-eq/kg) compared to PET (≈3.0 kg CO2-eq/kg). Key challenges, including moisture sensitivity (equilibrium moisture content ~25% at 75% RH), raw material molecular-weight variability (±20%), and scalability, are outlined, along with future research directions, such as enzymatic extraction and the development of water-resistant, compostable formulations aimed at advancing psyllium gum toward viable next-generation sustainable food packaging materials.