Sustainable recovery and characterization of high-purity hemp seed protein concentrate for functional food innovation

Abstract

The growing interest in sustainable protein sources has highlighted the potential of oilseed by-products within circular economy frameworks. This study aimed to obtain a high-purity protein concentrate (HPC) from hemp seed cake of the Secuieni-Jubileu variety and to perform its comprehensive physicochemical and biochemical characterization. The defatting process was conducted using n-hexane (1:4 w/v) over 24 hours, followed by vacuum drying and solvent volatilization. Protein extraction was carried out in 0.1% NaCl solution (1:10 w/v), with gentle agitation for 30 minutes at 21 ± 2 °C. The resulting extract was filtered, and protein was precipitated by centrifugation (4000 rpm, 15 min), followed by washing and drying at 50 °C for 24 h. The HPC was analyzed via standard AOAC methods for proximate composition and by acid hydrolysis for amino acid profiling. The resulting HPC contained 74.15% protein (d.m.), low fat (0.45%), and notable dietary fiber (18.47%), with moisture reduced to 3.12%. Amino acid profiling revealed a balanced composition, including high levels of leucine (8.17 g/100 g protein), arginine (10.92 g/100 g), and isoleucine (5.56 g/100 g), while the amino acid score indicated excellent nutritional value, despite sulfur-containing amino acids being limiting. These findings underscore the potential of hemp seed cake as a viable raw material for sustainable protein extraction, offering promising implications for future functional food innovation.