Collagen Peptides Leached From COD Skins By Natural Deep Eutectic Solvents (NADES) And Recycling

In recent years,collagen peptides have been favored by people for their important nutritional value.The traditional method for extracting collagen peptides is usually acid/alkali method or enzymatic method.There are problems such as low extraction rate,high cost,so traditional method must be advanced sooner or latter.NADES is a natural green eutectic solvent that can selectively open and reconstruct hydrogen bonds without toxic effects and can be biodegraded.It has been applied to the extraction of natural products.The innovation of this article lies in leaching collagen from squid skin by NADES,which has high selectivity,low cost,and easy to up scale.The highlight is that raw materials and solvents can be recycled,green and sustainable.The paper focuses on the extraction process of collagen peptides and fish oil,with optimizing the extraction process and recycling of NADES.The Cod skins will be leached by NADES,then the organic precipitants were added to precipitate collagen from the NADES-leached system.And the collagen precipitation rate was measured by UV,HPLC.The influence of factors such as the type of precipitants,the proportion of the precipitants,the temperature,the amount,and the time on the collagen precipitation rate was tested.Orthogonal design experiments were used to optimize,the results showed that when the ethanol concentration was 16%,the temperature was 25 ?,the mixed alcohol amount was 6 times,and the precipitation time was 20 h.The yield of collagen was up to 78.76% and the purity was up to 68.94%.Fish oil was extracted from the cod skin into the solvent by Soxhlet extraction method.Explore the extraction of fish oils by ethers,lipids and alkanes.Using the GC-MS to analyze the content of oleic acid,EPA,DHA in fish oil.Finally,select ethyl acetate as the best extraction solvent,and optimize the time of extraction.The experiment showed that when the ethyl acetate was the extraction solvent,the time of extraction was 12 h,the yield of fish oil was up to 2.79%,the relative content of oleic acid was up to 27.84%,the relative content of EPA was up to 10.91%,and the relative content of DHA was up to 15.13%.At the same time,the slope coefficient method was adopted to deduce the reaction coefficient in the cable extraction process.It was proved that ethyl acetate and fish oil were mainly combined in the form of 1:1(mass concentration)during the extraction process.NADES circulation leaching was performed on Dried squid cod skin,Dried narrow squid skin,Dried defatted squid cod skin,and Dried defatted narrow squid cod skin.Under the optimal conditions,Experiments showed that after 5 cycles,th e yield of the four fish skins was between 64.35% and 85.90%,and the purity was between 61.39% and 81.83%.After 7 cycles,the yield of the four skins was between 61.92% and 80.80%,and the purity was between 52.35% and 71.19%.The predictive analysis of the scale and price of the collagen industry's future development suggests that the dried defatted narrow squid skin can be the best source of collagen peptides.