| Fish muscle is rich in nutrient,including many basic compositions such as moisture,proteins and fat,and many nutrition such as amino acids and fatty acids,which is an essential source of nutrition for humans.The flesh is rich in a variety of essential amino acids and polyunsaturated fatty acids,which is of great significance to human beings.Lateolabrax maculatus is widely distributed in China,and it is one of the important economic fish.It has the advantages of fast growth,short culture cycle,delicious meat and high nutritional value.At present,the research on L.maculatus mainly focuses on ecological distribution,eco-physiology,taxonomic status and reproductive biology,etc.,and there is little systematic analysis of its muscle nutritional components and lack of muscle nutritional data.In this study,the muscle of L.maculatus was taken as the research object,and the expression levels of basic nutritional components,amino acids,fatty acids and fat-related genes in different parts of muscle were detected.By comparing with the basic nutritional components,amino acids and fatty acids in different fish muscles,the nutritional characteristics of L.maculatus muscle were analyzed,which provided theoretical data for the public to understand the nutritional value of L.maculatus muscle and the development and utilization of related products.The main results are as follows:1.The muscle of L.maculatus is rich in various nutrients.The moisture in the muscle of L.maculatus is the main component(about74.81%),and the contents of other nutrients from high to low are protein(about21.09%),fat(about 2.61%)and ash(about 1.48%).L.maculatus muscle has the advantages of low fat content and high protein content,which can meet the needs of healthy diet.Glutamate(Glu)is the highest amino acid in the muscle of L.maculatus,accounting for 16.10% of the total amino acids.Essential amino acids accounted for42.34%,and the ratio of essential amino acids was 0.74.Among them,lysine(Lys)has the highest content(17.9%)and is the main essential amino acid.The muscle of L.maculatus is rich in essential amino acids and belongs to high-quality protein.The umami amino acid content accounts for 41.55%,among which glutamic acid(Glu)is the highest and the main umami amino acid.The umami amino acids in the muscle of L.maculatus are diverse and high in content,which can meet people’s dietary taste requirements.Linoleic acid(C18:2n6c)is the highest fatty acid component(27.17%)in the muscle of L.maculatus.The saturated fatty acids in the muscle of L.maculatus account for about 28% of the total fatty acids,and the content is low,among which palmitic acid(C16:0)is the highest saturated fatty acid.Monounsaturated fatty acids account for about 32% of the total fatty acids in the muscle of L.maculatus,and oleic acid(C18:1n-9)is the highest monounsaturated fatty acid.Among the fatty acids contained in the muscle of L.maculatus,polyunsaturated fatty acids are the highest,accounting for about 42% of the total fatty acids,and linoleic acid(C18:2n6c)is the highest,which is the main polyunsaturated fatty acid.The content of essential fatty acids in the muscle of L.maculatus accounts for about 29% of the total fatty acids,among which linoleic acid(C18:2n6c)is the highest and linolenic acid(C18:3n-3)is relatively low.EPA(C20:5n3)and DHA(C22:6n3)are relatively high in the muscle of L.maculatus,accounting for 2.91% and 7.23% respectively.The muscle of L.maculatus mainly contains polyunsaturated fatty acids and monounsaturated fatty acids,and the content of saturated fatty acids is low,which has the functions of lowering blood sugar,regulating blood lipid and lowering cholesterol.2.The muscle of L.maculatus has unique nutritional characteristics.In order to clarify the nutritional characteristics of the muscle of L.maculatus,ten kinds of common freshwater fish(Ctenopharyngodon idella,Mylopharyngodon piceus,Pelteobagrus fulvidraco,Channa argus,Carassius auratus,Aristichys nobilis,Siniperca chuatsi,Monopterus albus and Oncorhynchus mykiss)and ten kinds of common marine fish(Larimichthys crocea,Epinephelus lanceolatus.Scophthalmus maximus,Pagrus major,Salmo salar,Sardina pilchardus,Larimichthys polyactis,Eleginus gracilis,Pampus chinensis,Cynoglossus semilaevis)were mixed.By comparing the contents of basic nutrient in muscle of L.maculatus with those of ten kinds of freshwater fish and ten kinds of marine fish,the results showed that the moisture content in muscle of L.maculatus was 76.58%,which was similar to that of most fish,indicating that the moisture content in muscle of L.maculatus was normal.The protein content in the muscle of L.maculatus is the highest among the ten kinds of freshwater fish and ten kinds of marine fish,and the protein/moisture ratio is the highest among the ten kinds of freshwater fish and ten kinds of marine fish,and the fat/moisture ratio is relatively low,so it has the characteristics of "low fat and high protein".Glutamic acid(Glu),aspartic acid(Asp)and lysine(Lys)are the main amino acid components in the muscle of L.maculatus,which are similar to freshwater fish grass carp,black carp,yellow catfish,snakehead and marine fish,such as grouper,red snapper and tongue sole.The content of essential amino acids in the muscle of L.maculatus is medium in both freshwater and marine fish,and the content of major essential amino acid lysine(Lys)is high in the muscles of ten freshwater and marine fish,while the total content of umami amino acid and major umami amino acid glutamic acid(Glu)are high in the muscles of ten freshwater and marine fish.The content of palmitic acid(C16:0)in the muscle of L.maculatus is the lowest in both marine fish and freshwater fish,and the content of saturated fatty acids in freshwater fish is only higher than that in crucian carp,and the content is the lowest in marine fish.The content of monounsaturated fatty acids in the muscle of L.maculatus is in the middle level among ten kinds of freshwater fish and ten kinds of marine fish,and the content of oleic acid(C18:1n-9)is in the high level.The content of polyunsaturated fatty acids in the muscle of L.maculatus is relatively high,and linoleic acid(C18:2 n-6c)is relatively high in the muscles of ten freshwater fishes,second only to crucian carp,and the highest in the muscles of ten marine fishes.The contents of DHA and EPA,essential fatty acids linoleic acid(C18:2 n-6c)and linolenic acid(C18:3n-3)in the muscle of L.maculatus are at a high level in ten kinds of freshwater fish and marine fish.3.There are differences in muscle nutrients in different parts of L.maculatus.In all the muscles of L.maculatus,the moisture content is the highest,with the highest moisture content in the back muscles(75.83%)and the lowest in the belly muscles(70.33%).The protein content in the back muscle is the highest in L.maculatus,and the content in other parts is relatively low.Among the four muscles of L.maculatus,the fat content of the back muscle is the lowest,which is 0.93%,the fat content of the lateral muscle and the tail muscle is 1.58% and 1.86% respectively,and the fat content of the abdominal bottom muscle is much higher than that of other parts,which is 5.96%.The back muscle of L.maculatus has the characteristics of high protein,low fat and high moisture content,which has high nutritional value and meets the requirements of healthy food.The amino acid content of muscle in different parts of L.maculatus is different,with the highest total amino acid content in back muscle and the lowest in belly bottom muscle.The content of essential amino acids in back muscles is the highest,accounting for 48.63%.Lys is the highest content of essential amino acids in muscles of all parts,and the content of back muscles is the highest,accounting for 10.18%.The content of umami amino acids in the back muscles is the highest in the four muscles,and the content in the abdominal bottom muscles is the lowest.Glutamate(Glu)is the highest umami amino acid content in muscles of all parts,and the back muscle has the highest content,accounting for 16.10%.The back muscle of L.maculatus is rich in amino acids,balanced in species and high in umami amino acids.The total fatty acid content in different parts of L.maculatus is quite different,the total fatty acid content in back muscle is the lowest,and the fatty acid content in belly bottom muscle is the highest.Oleic acid(C18:1n-9)is the highest fatty acid in different parts of L.maculatus,and the back muscle is the highest.The lowest content of saturated fatty acids in the muscle of L.maculatus is in the back muscle,with a content of 19.74%,and the highest content in the lateral muscle,with a content of 26.09%.Palmitic acid(C16:0)is the highest saturated fatty acid in the four muscles of L.maculatus,with the lowest content in the back muscle and the highest content in the lateral muscle.The content of monounsaturated fatty acids in the muscles at the bottom of abdomen is the highest,accounting for 37.32%,and the content in the muscles at the back is the lowest.The content of monounsaturated fatty acids in the muscles of the four parts of L.maculatus is the same,all of which are oleic acid(C18:1n-9),with the highest content in the muscles at the bottom of the abdomen,accounting for 30.62%.The content of polyunsaturated fatty acids in the muscle of the back of L.maculatus is the highest,accounting for 45.18%,and the content in the muscle of the belly bottom is 37.80%.Linoleic acid(C18:2n-6c)is the highest polyunsaturated fatty acid in the muscles of L.maculatus.The content of linoleic acid(C18:2n-6c)in the muscle of L.maculatus is the highest,accounting for29.61%.The content of essential amino acids in the back muscle of L.maculatus is the highest,accounting for 31.80%,and the content in the tail muscle is the lowest,accounting for 29.13%.Among them,the content of linolenic acid(C18:3n-3)is the highest in the muscle of the abdominal bottom,accounting for 2.87%.The contents of DHA and EPA in the back muscle of L.maculatus were the highest,7.68% and 3.29%,respectively,and the lowest,2.87% and 1.91%,respectively.The expression levels of various regulatory genes related to fat formation in different parts of muscle of L.maculatus were analyzed.Compared with the other three muscle tissues,the positive regulatory genes PPARγ,BMP2,BMP4,FGF1 and C/EBPα involved in fat formation were relatively higher in the ventral bottom tissue,which indicated that gene regulation in the ventral bottom muscle tissue was helpful to fat formation.At the same time,the expression of negative regulatory genes involved in fat formation was also detected in the ventral floor tissue,indicating that there is also a genetic regulatory mechanism to inhibit fat overexpression. |
PDF Full Text Request