Sequential Extraction of Valuable Bio-Products from Snow Crab ( Chionoecetes opilio ) Processing Discards Using Eco-Friendly Methods

• Published in: Marine Drugs
• Main Authors: Heather J. Burke, Francesca Kerton
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: snow crab; processing discards; eco-friendly; green extraction; vegetable oil; astaxanthin; Biology (General); QH301-705.5; Chionoecetes opilio; Snow crab
• Online Access: https://doi.org/10.3390/md21060366; https://doaj.org/article/b21c1c6527f14187b2a1f979e4251d32

Green extraction methods using a combination of mechanical, enzymatic, and green chemical treatments were evaluated for the sequential extraction of carotenoid pigments, protein, and chitin from crab processing discards. Key objectives included avoiding the use of hazardous chemical solvents, conducting as close to a 100% green extraction as possible, and developing simple processes to facilitate implementation into processing plants without the need for complicated and expensive equipment. Three crab bio-products were obtained: pigmented vegetable oil, pigmented protein powder, and chitin. Carotenoid extractions were performed using vegetable oils (corn, canola, and sunflower oils), giving between 24.85% and 37.93% astaxanthin recovery. Citric acid was used to demineralize the remaining material and afforded a pigmented protein powder. Three different proteases were used to deproteinate and isolate chitin in yields between 17.06% and 19.15%. The chitin was still highly colored and therefore decolorization was attempted using hydrogen peroxide. Characterization studies were conducted on each of the crab bio-products isolated including powder X-ray diffraction analysis on the chitin (80.18% crystallinity index, CI, achieved using green methods). Overall, three valuable bio-products could be obtained but further research is needed to obtain pigment-free chitin in an environmentally friendly manner.