Evaluation of cassava leaves extract as a material to produce biopolymer-based films

Abstract

Cassava leaves are protein-rich by-products, still unexplored, largely produced as by-products in tropical and subtropical countries. This study proposed the production of cassava leaves extract-based films with added glycerol using the casting methodology. First, the influence of alkaline extraction parameters on the release of the amount of protein, carbohydrates, and total solids was studied by Central Composite Rotational Design with 17 experiments. Solid-liquid ratio, temperature, pH, and their combinations had a significant effect on protein and carbohydrate extraction. Out of 17 experiments, 6 were able to form a film that was easily removed from the silicone plates and showed good handling. Those extracts have more than 2 g of protein in solution and total solids content higher than 1.5%. All films were dark in color with highly influenced by extract color. The protein-carbohydrate ratios were different in the six extracts, which resulted in films with distinct thickness, color, morphology, mechanical properties, and surface characteristics. Thus, this study proposes new insights into the reuse of agro-industrial byproducts and biopolymer-based films aiming to build a more sustainable and eco-friendly food industry.