Migration Of Nutrients And Their Antioxidant Activities In Aristichthys Nobilis And Salmon Salar Head Soup During Cooking

Since ancient times,the A.nobilis head soup has been favored by Chinese people for its fresh but not fishy,fat but not greasy and milky fish soup.As the offal of Salmon Salar processing,Salmon Salar head is rich in nutrition,but it is seldom used for direct processing.The traditional Chinese method of processing fish head is considered to boil the Salmon Salar head into fish head soup to improve its use value and economic value.Fish head soup is boiled through a series of chemical and physical reactions.The chemical components in the soup are both the original components transferred from food and the new components formed by the interaction of the original components.These components can also form new supramolecular structures through intermolecular secondary bond interactions and assemble into micro-/nano-sized aggregates,thus changing the chemical and physical properties of the soup.In this paper,fresh water head A.nobilis head and sea water head of Salmon Salar head as the research object,the nutrition index and safety index were evaluated in detail.We cooked A.nobilis head and Salmon Salar head into fish head soup,and studied the migration of nutrients in the cooking process.The formation and structure of nano-micro particles in fish head soup were studied by optical microscope and laser confocal microscope.Six chemical methods were used to study the antioxidant activity of fish soup with different treatments.The main research contents and results are as follows:?1?The nutritional components and quality of A.nobilis,Salmon Salar and T.obesus heads were investigated and evaluated to provide basic data and theoretical support for fish head consumption.The composition and contents of general nutrients,fatty acids,amino acids,minerals and heavy metals residue in three kinds of fish heads were measured and evaluated by national standards and literature.There was a significant difference in the crude fat content of the three fish heads?P<0.05?,the highest crude fat content was Salmon Salar?14.37%±2.63%?,followed by T.obesus?10.70%±0.97%?,and finally A.nobilis?3.82%±0.04%?.The crude protein content of T.obesus head was significantly higher than A.nobilis head and Salmon Salar head?P<0.05?.All three fish heads are rich in unsaturated fatty acids,accounting for 61.30%⁸2.40%of the total fatty acid content.All three fish heads contain plenty of EPA and DHA,especially T.obesus head.The EPA and DHA in T.obesus are 65.12%of total fatty acid,which was significantly higher than A.nobilis head and Salmon Salar head?P<0.05?.The amino acid composition of the three types of fish head is relatively reasonable.The proportion of total essential amino acid/total amino acid was 39.73%⁴0.16%,and the amino acid scores were all greater than 100,indicating that the three types of fish head could be used as the source of high-quality amino acid.The three types of fish heads are rich in minerals,among which the contents of K and Na were high in the constant elements,and mere the same of Fe and Zn in the trace elements.The heavy metal residue?Pb,As,Hg,Cr,Cd?of the three fish heads did not exceed the national limit,indicating that the source of the fish head is safe and healthy.?2?During the cooking process of A.nobilis and Salmon Salar head soup,nutrients such as lipids,proteins,sugars,minerals,solids and vitamins in the fish head tissue migrated into the soup as the cooking time prolonged.When the cooking time is 150 min,the total amount of fatty acids,lipids,sugars,and tocopherol isomers in the soup is maximized,and heating is continued,which causes degradation of these substances and lowers the content in the soup.The water-soluble protein,minerals and solids were stable due to their properties,and their content continued to increase in the soup,but there was no significant difference between the cooking time of 180 min and 150 min?P>0.05?.The content of nutrients in the Salmon Salar soup is higher than that of the A.nobilis head soup,which is consistent with the content of each nutrient in the fish head meat,and the sea salt in the head of the sea fish can promote the dissolution of the material in the Salmon Salar head soup.Using light microscopy to study the formation of micro-nano particles in squid and Salmon Salar soup,it was found that when the cooking time was 150 min,the nutrients in the soup were most dissolved,and there were spherical particles with stable properties in the soup.The microscopic structure of the soup was studied by laser confocal microscopy.It was found that neutral triglycerides self-assembled to form spherical particles,while proteins,phospholipids and sugars were distributed on the periphery of the fat globules,and the three could be combined lipoproteins,glycoproteins and glycolipids exert their physiological functions.?3?The particle size distribution of A.nobilis and Salmon Salar head soup treated by different methods such as coarse filtration,centrifugation,microfiltration and ultrafiltration was determined by Malvern laser particle size analyzer.The results showed that after a series of different treatments,the granules in the soup were processed.The average particle size was significantly smaller?P<0.05?,and particles of different particle sizes in the soup could be initially separated.The in vitro antioxidant capacity of A.nobilis and Salmon Salar head soup with different particle sizes was determined by six chemical methods.The results showed that the DPPH free radical scavenging ability of the A.nobilis and the Salmon Salar soup was similar to that of the superoxide anion radical?P>0.05?.The Fe²⁺chelation ability and ABTS free radical scavenging ability of the A.nobilis head soup are greater than that of the Salmon Salar head soup?P<0.05?.The hydroxyl radical clearing ability and total reducing ability of the Salmon Salar head soup are greater than that of the A.nobilis head soup?P<0.05?,but all of them are as follows:original soup>centrifugation>microfiltration>ultrafiltration.Different differences in antioxidant capacity may be due to the fact that the separation process changes the chemical composition and structure of the particulate matter in the soup,resulting in a decrease in antioxidant power or due to differences in the chemical principles of different antioxidant assays.