Physicochemical properties of bioactive bioplastics based on cellulose from coffee and cocoa by-products

Abstract

Plastic pollution has become a critical environmental issue due to the extensive use of petroleum-derived plastics, which persist in ecosystems and pose significant challenges to sustainability. This study evaluated the physicochemical properties of bioactive bioplastics made from cellulose extracted from coffee by-products (spent coffee grounds) and cocoa (pods), which were proposed as a sustainable alternative to mitigate the environmental impact of petroleum-derived plastics. The formulation of the bioplastics involved varying proportions of cellulose (1, 3, and 6 %) in combination with bioactive cacao extracts (0.05 % and 0.15 % w/v). A comprehensive array of physicochemical properties was analyzed, encompassing parameters such as color change, whiteness index, water activity, solubility, transparency, flexibility, antioxidant capacity, and biodegradation. The results demonstrated that the bioplastics with 3 % cocoa pod cellulose (CMC) and 0.05 % bioactive extract exhibited the highest whiteness index (86.9) and the most excellent flexibility (32.24 N). In contrast, formulations comprising 6 % CMC exhibited reduced water activity (0.49). Bioplastics containing 1 % coffee cellulose (PC) and 0.15 % bioactive extract demonstrated a high antioxidant capacity (0.38 mgTE/L). Furthermore, it was observed that an increase in cellulose content led to a decrease in the biodegradation rate, with the control achieving 98 % degradation within 35 days. This study provides fundamental information for designing bioplastics with specific properties, thereby promoting the development of more sustainable and environmentally friendly packaging technologies.