Valorization of sturgeon notochord to obtain antioxidant non-collagenous peptides from the purification process of chondroitin sulfate

Notochord is a cartilage-related by-product of sturgeon processing. To increase the utilization of notochord, we have developed an efficient and eco-friendly extraction process that could recycle non-collagenous peptides during chondroitin sulfate (CS) extraction. Alkaline treatment and ultrafiltration were the two critical steps in the overall extraction process. The results of SDS-PAGE and amino acid composition analysis demonstrated that peptides in low molecular fraction were mainly derived from non-collagenous protein. The non-collagenous peptides exhibited high antioxidant activity. The structural analysis (UV, FTIR, 1H NMR and SAX-HPLC) of CS in high molecular fraction proved high purity CS was obtained using new extraction process. The yield of noncollagenous peptides and CS were 16.8% and 14.5%, respectively. Including undenatured type II collagen, the total utilization rate of notochord was increased to 75.6%. It truly realized the maximum utilization of sturgeon notochord. This extraction process can be used as a reference for other cartilage-related by-products.