Study on the extraction of collagen from channel catfish bone and bone meal

Protein in fish bones will affect the absorption of calcium. If protein was extracted from fish bones and calcium was retained in the bones, not only the protein can be used separately, but also the high calcium can be more easily absorbed. So we can achieve the vision of zero waste in the use of resources. In this paper we chose different reagents to extract collagen from channel catfish (Ictalurus punctatus) bones and partially characterized the collagen. The results showed thatunder the condition of 4℃, non-collagens could be removed completely from fish bones by soaking in 0.1 M NaOH for 6 hours followed by 2.5% NaCl for 6 hours; lipids could be removed by soaking with 10% butyl alcohol. Then colorless and tasteless collagens were extracted with 0.1 M citric acid for 3 days, and the extraction ratio was 11.87%. The extracts were purified further by salting-out and dialyzing. The viscosity of collagen increased as the concentration was condensed and the temperature for denaturation was 33.9℃. SDS-PAGE showed that the collagens were composed of two chains and one chain. The content of Ca in bone was high up to 60%. The bone meal with protein free was added in biscuits and didn't cause taste and smell difference. So it could be used in food processing as a good calcium additive.