Rapeseed Meal Biorefining: Fractionation, Valorization and Integration Approaches

Rapeseed meal (RSM) is an agricultural by-product with high potential as a biorefining feedstock due to its abundance, costs, and valorizable fractions, including proteins (such as cruciferin and napin), phenolics (such as sinapine and its derivatives, tannins and lignin), polysaccharides (cellulose, hemicellulose, and pectin), phytic acids and glucosinolates. RSM is also an important candidate for a whole-crop biorefining scheme, due to its integration potential with biorefining of other rapeseed-derived fractions, including rapeseed oil and straw. To date, research and development into holistic integrated RSM biorefining is limited, with the majority of the literature focusing on the valorization of a single fraction, typically proteins or phenolics, overlooking the potential of other fractions as well as the post-processing residue. This review is designed to aid efforts to develop a holistic RSM biorefining scheme through a comprehensive assessment of processing and applications of valorizable RSM fractions within an integrated biorefining context. The myriad of extraction, purification, modification, and applications for each fraction are discussed to elucidate their valorization potential and highlight major gaps within the literature that need to be addressed in the future. Finally, the current literature on RSM biorefinery and a proposal for a more holistic integrated biorefinery scheme are discussed and important considerations, challenges, and future steps for the development of RSM and rapeseed biorefinery are provided. The perspective, insights, and recommendations provided by this review will be beneficial for the future development of holistic integrated biorefineries for rapeseed and other biomass feedstocks in general.