| Rainbow trout,also named "colorful fish" or "fish falls",is a kind of fish of northern North America and the west coast of the Pacific Ocean,and it is one of the four varieties of fresh water aquaculture that has a good quality and high yield.Rainbow trout have a long body,and the fish bone accounted for around 30%of the fish,which contains fish oil and protein with high nutritional value.If all the fish bone were all discarded,that will be not only a serious environmental pollution but also a waste of resources.It will be a great meaning,if put the fish bone to a nutritional value products.The purpose of this study is to prepare a kind of seasoning produces with high nutritional value which make the rainbow trout bone as raw material.The main research contents and results are shown as follows:1.Fish oil of rainbow trout was extracted by enzymolysis technology and single factor analysis,and the fatty acids were identified by gas chromatography-mass spectrometry technology.Results showed that the highest yield of fish oil was the hydrolysate using the alkaline protease enzymolysis.Results showed that the optimum extraction parameters of enzymatic hydrolysis were as follows:the optimum enzymolysis condition was 2000 U/g adding amount of alkaline protease,ratio of water to material 1:1,pH 7.5,at 55? for 3 h.It was shown that the main composition of rainbow trout bone oil is unsaturated fatty acid,which content is 80.4%.The relative content of monounsaturated fatty acid and polyunsaturated fatty acid were 76.9%and 23.1%.The total content of EPA and DHA was 3.4%.2.Fish bones were hydrolyzed by five different kinds of enzymes,including alcalase,flavourzyme,papain,netruse and trypsin.The hydrolysates were centrifuged and the supernatant which riched in soluble peptides and small proteins was removed.The supernatant were measured on the nutritional score,chemical score,essential amino acids index,and compared from the taste(free amino acid)and flavor.The results showed that the total amount of 8 essential amino acids in human body was 644.8 mg/g N.From the AAS evaluation,the highest score of amino acid in rainbow trout bone is lysine,followed by methionine and cysteine.As the first limiting amino acid,the score of valine was the lowest.Evaluated from the CS,the score of lysine was the highest in rainbow trout bone,followed by threonine.At the same time tryptophan was the first limiting amino acid.The EAAI of the rainbow trout fish bone was 20.075.Alcalase was the best enzyme,with the index of the degree of hydrolysis,nitrogen recovery rate,molecular weight.The peptide less than 3000 Da accounted for 89%by alcalase,which were far more than other enzyme.The free amino acid which came from the five different enzymatic hydrolysis products were measured by liquid chromatography-mass spectrometry technology,the research found when using the alcalase hydrolyzed the fish bone,the bitter were at the least and the taste were the best.Volatile flavor compounds were determined by solid phase microextraction gas chromatography mass spectrometry.The results showed that when using the alcalase hydrolyzed the fish bone,the content and breed of volatile flavor compounds were the highest.3.In order to make sure the optimum technological conditions of flavoring of rainbow trout fish bone which were fully utilized,I put the ratio of material to liquid,pH value,cooking temperature as variables,and determined the texture and color and the optimum adding amount of Xanthan gum as screening criteria.The results show that the seasoning which mixed with water of 1:1,and cooked at 121? for 30 min in the atmosphere of pH=7.0,were the best which were bright,good taste,and nourished.Added different kinds and different contents of the thickener to the semi-finished products.Determinated the texture,and took the shuanghui soup as a control standard,to select the best thickener and the amount of it.After the comparison,it found that the best thickener was Xanthan gum.It would be meet and exceed shuanghui soup when the amount of Xanthan gum were 2%.4.The fatty acid and amino acid included in the four kinds of fish seasonings,were measured and compared with each other.Found that four kinds of seasonings are all put the octadecanoic acid and octadecadienoic acid as the main ingredient.After the enzymatic hydrolysis process,the kind of the fatty acid hold the line,while the content of it has a certain degree of improvement.Among them,the most significant increase was the Omega-3 fatty acids.Compared to the soup,after spray drying technology,the content of the Omega-3 fatty acids increased nearly 140 times.Rainbow trout fish bone contains a variety kind of amino acids,especially the essential amino acids.After enzymatic hydrolysis,the amount of amino acid in raw material increased,especially the phenylalanine.After spray drying,the contents of all kinds of free amino acids had a certain degree of increase.In summary,rainbow trout fish bone is a high nutritional value of food raw materials,which has potential development value. |
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