Peptide-Enriched Materials from Rapeseed Meal Protein: Structural Valorization Strategies and Properties Improvement for a Circular Economy

The agri-food industry generates substantial biowaste, often discarded or used as animal feed, yet rich in bioactive compounds with potential for a wide range of applications. This study aims to valorize rapeseed meal biowaste, a byproduct of oil production, to develop biocompatible, protein-based composites with industrial applications, supporting a shift towards a bio-based circular economy. We developed a scalable, eco-friendly protein extraction process, yielding a high-quality protein-enriched extract. Through pyrolysis, rapeseed meal protein extraction residue was converted into bio-oil and bio-char, enabling full resource recovery aligned with sustainability principles. The study introduces a method for developing partially flexible biomaterials from raw, protein-rich rapeseed meal, utilizing crosslinking with epoxides and compression molding. Protein-based blends with glycerol, cross-linkers, and denaturants were thermally processed to improve material strength and durability. Then, collagen and rapeseed meal protein hydrolysates, obtained by enzymatic proteolysis, were incorporated to modulate flexibility and reduce water absorption. Mechanical and thermal properties of the composites were modulated by adjusting ratios of rapeseed meal protein and collagen hydrolysates, which served as effective plasticizers. Our findings demonstrate that rapeseed meal-based materials can be tailored for potential industrial applications, meeting demands for bio-related alternatives. This work represents an initial step toward sustainable, cost-effective bio- based materials, promoting the recovery and valorization of agricultural byproducts within the framework of a circular economy.