Biotransformation of Camelina Meal via Pretreatment and Fermentation for Functional and Nutritional Upgrading

Camelina sativa, an oilseed crop of the Brassicaceae family, has seen increased cultivation in North America in response to the rising demand for biofuels over the past two decades. With this growth, camelina meal, a byproduct of oil extraction, has emerged as a promising yet underutilized resource, particularly for applications in animal nutrition. This study aimed to evaluate the potential of camelina meal as a substrate for submerged fungal fermentation and to examine how this bioconversion affects its physicochemical and nutritional properties. The influence of mild pretreatments (unwashed, washed only, and washed/dried and ground) on fermentation outcomes was also assessed. Camelina meal is naturally rich in residual oil, n-3 fatty acids, and high-quality protein and amino acids. Following 120 hours of fermentation with three GRAS (generally regarded as safe) fungal strains (Aspergillus niger, Aspergillus oryzae, and Aureobasidium pullulans), significant enhancements (p < 0.05) were observed in crude protein content, total phenolic content (TPC), antioxidant activity (DPPH/ABTS), and bulk density. Notably, A. niger fermentation resulted in up to a 39.2% increase in protein, a doubling of TPC (from 10.49 to 24.04 mg GAE/g in dried meal), and marked improvements in antioxidant potential. Antinutritional compounds such as phytic acid were reduced by 48–81%, while crude fiber content decreased from 21.3% to 11.3%. Pretreatment, especially combination of washing, drying and grinding, enhanced phenolic release and antioxidant capacity, likely due to increased substrate surface area. Fermentation also modified functional properties, increasing bulk density (beneficial for packaging) and reducing water absorption capacity, making the product more suitable for thin formulations. Overall, this study demonstrates that fungal fermentation is a sustainable and effective strategy to valorize camelina meal, transforming it into a nutrient-enriched ingredient suitable for animal feed and potential functional food applications. Strain-specific enhancements (e.g., A. niger for protein and phenolic enrichment; A. pullulans for selective protein enhancement) and pretreatment optimization are critical to maximizing bioconversion efficiency. These findings contribute to advancing circular bioeconomy initiatives by repurposing agricultural residues into high-value products through environmentally friendly microbial processes.