Mechanism Of Bitterness Formation And Control Methods Of Protein Hydrolysis Of Cod Bone

China is a maritime country,in which the fish production accounts for about 60% of the total national aquaculture.In the process of fish industry,a large amount of by-products will be produced inevitably and fish bone accounts for about 15%.Most of these by-products are discarded as waste,which caused a great waste of resources.Cod is one of the most caught fish species.Cod is a high-quality species that is rich in protein,vitamins and minerals,and has a low level of fat content.After enzymatic hydrolysis of cod bone,it can produce small molecular peptides with specific physiological and functional activities.These aquatic peptides play an important role in promoting growth,lowering blood pressure,anticoagulation,anti-oxidation and many other aspects.However,after the enzymolysis,the protein produced a strong bitter taste,which will degrade the sensory quality and affect the fish bone product development and its food market prospects.In this study,mechanism of bitterness formation and control methods of protein hydrolysis of cod bone were investigated.The effects of hydrolysis conditions and the composition of bitter substances on bitter taste were studied.At last,the study using the existing debittering methods to debitter the hydrolysate of cod bone,laying a theoretical foundation for cod bone by-product products.The main results of this study are as follows:1.The constituents of raw cod bone were investigated,results showed that the content of protein in cod bone material was 17%,which covered all the essential amino acids in the human body.Which imply cod bone protein could be used as a high quality protein.2.To study the effect of hydrolysis conditions on the bitternes s intensity of hydrolysate of cod bone.Cod bone protein was hydrolyzed by neutral proteases,alkaline proteases,flavourzyme,papain and animal proteases,respectively.With the increase of the enzymatic time,the bitterness of the hydrolysate increased first and then decreased.Among them,the hydrolyzate by alkaline protease has the highest bitterness intensity,and the hydrolyzate by papain has the lowest bitterness intensity.3.To study the effect of the composition of the hydrolysate on the bitterness intensity of the hydrolysate of cod bone.The bitter taste produced during the hydrolysis mainly caused by small peptides produced during the enzymatic hydrolysis.Hydrophobicity of polypeptide,molecular weight,metal ion composition and amino acid composition are all important factors affecting bitterness.The molecular weight of peptides that affect bitterness is generally lower than 6000 Da.The content of metal ions can also increase bitterness when it reached a certain amount.Hydrophobic amino acids and alkaline amino acids can also enhance bitterness intensity.4.The study of debilitating methods with ?-cyclodextrin and seasoning.That results showed that the bitterness intensity decreased first and then approaches a plateau with the addition of the ?-cyclodextrin.In view of the excessive addition amount,the sensory properties and the turbidity of the sample will also be affected.Finally,it is determined that 1.5% of ?-cyclodextrin as the optimal addition.