Cocoyam is an Unconventional, Innovative, and Sustainable Source of Starch with Potential use in Sleek and Functional Biodegradable Films

Abstract

The growing interest in sustainable biopolymers has highlighted cocoyam starch as a promising material for functional biodegradable packaging film development. This study evaluates its physicochemical, structural, thermal, rheological, and mechanical properties to determine its suitability for packaging. Cocoyam starch contains moisture (9.15%), protein (0.68%), lipid (0.57%), ash (2.82%), and resistant starch (5.61%), offering moderate digestibility. Total soluble phenolic compounds are quantified at 50.56 mg GAE·100 g−1 of starch, which influences the physicochemical properties. Cocoyam starch presented a semi-crystalline structure comprising both Type A and B starches, along with monohydrated calcium oxalate crystals. The gelatinization temperature is determined to be 65.81 °C, with an associated gelatinization enthalpy of 15.38 J g−1. Gel retrogradation exhibits a rate of 38.52%. Rheological properties reveal a high peak viscosity and breakdown, suggestive of a high amylopectin content in the starch. Cocoyam starch films demonstrate variations in thickness and neutral instrumental color parameters. Mechanical analysis reveals that these films have lower tensile strength but higher elongation to rupture compared to cassava starch films, likely due to the intermolecular connections formed by cocoyam starch. Crystallography patterns of films indicate structural transformations, including calcium oxalate phases and semi-crystalline structures, underscoring their potential applications in biodegradable packaging materials.