Preparations Of Cod Bone Proteins And Its Nutritional Seasonings

China is a maritime country,in the process of fish industry,a large number of fish bones,skin and scales will be produced inevitably.These by-products are often discarded as waste or processed into animal feed to use again,which is a great waste of by-products resources.The smell of cod is slightly.Therefore,if the by-products,such as fish bone,be developed reasonably,from the aspects of nutrition,health and safety to promote the value and economic benefits,there will be a very broad market prospect and practical significance.In this study,the constituents of raw cod bone were investigated,and the extraction of protein from cod bone was optimized by orthogonal experiment on the basis of single factor experiment.The results showed that the content of protein in cod bone material was 16%,and the amino acid composition was rich that essential amino acids accounted for 42.19%of the total amino acids.When the extraction temperature was 120?,pH was 9,extraction time was 60 min,and the liquid to liquid ratio was 1:3,the extraction rate of cod bone protein was the highest,and the protein extraction rate was 60.10%.From the SDS-PAGE electrophoresis,the molecular weight of the extracted cod bone protein was mostly distributed at 70 KDa?130 KDa.The essential amino acids in the extracted cod bone protein accounted for 32.56%of the total amino acids,and unsaturated fatty acids accounted for 22.5%of the total fatty acids,which imply cod bone protein could be used as a high quality protein.Cod bone protein was hydrolyzed by flavourzyme and trypsin,respectively.Protein was hydrolyzed by flavourzyme for 3.0 h at optimal conditioat,hydrolysis degree(DH)and nitrogen recovery(NR)rate were 14%and 38.34%;protein was hydrolyzed by trypsin for 3.0 h at optimal conditioat,hydrolysis degree(DH)and nitrogen recovery(NR)rate was 8.82%and 37.41%,respectively.The total amino acid content of the enzyme hydrolysate was 942.55 mg/g in which essential amino acids accounted for 47.63%.Bitter amino acid accounted for 51.80%and 27.28%of total free amino acids in flavourzyme and trypsin enzyme system,respectively,which made the solution had a strong bitter taste.The first limiting amino acid is valine,and the nutritive value is equal to that of beef.The volatile compounds detected in flavourzyme system were 7 alkanes,7 olefins,10 alcohols,9 aldehydes,2 ketones,8 acids and 10 other substances,and 6 alkanes,6 kinds of alkenes,10 alcohols,aldehydes,2 ketones,9 acids and 11 other substances were detected in trypsin system.In all volatile compounds,alcohols,aldehydes,ketones,acids were considered to play a major role.The most molecular weight fraction of polypeptide protein in flavourzyme system hydrolysates was 5000 Da?7000 Da,and that in trypsin system hydrolysate was 1000 Da?3000 Da.71 unique sequences identified by UPLC-Q-TOF.In the 71 peptides,the most peptide composition were less than 20 amino acids and mainly concentrated in 7?13 amino acids;Peptide Ranker was used to predicte activities of the peptides and 12 peptides may have the activities,the highest score was 0.88 but the lowest was 0.54,peptide fragments by flavorzyme were 2 but were 10 by trypsin.Cod bone protein powder were made and the protein concentrate reached 97.420%.Then the hydrolysates at different time intervals were detected by electronic nose,hydrolysates by flavourzyme for 3.0 h can be distinguished from the sample at the other time points,hydrolysates by trypsin in 0.5 h?3.0 h can not be distinguished from each other,but two kinds of enzymatic products can be distinguished from cod bone protein sample;hydrolysates had a obvious bitterness detected by electronic tongue,followed by umami,astringency,and salty taste was also more obvious,the acidity was not obvious;from the human sensory evaluation results,cod bone protein solution and hydrolysates by flavourzyme for 3.0 h and by trypsin for 1.0 h had a relative higher evaluation score.The liquid seasoning was processed by protein extract and hydrolysates,the study showed that the products added 1.50%xanthan gum had a better structure characteristics.