Analysis Of Nutritional Components In Three Species Of Tuna From South China Sea And Anti-fatigue Activity Of The Muscle Protein Hydrolysates

Auxis tapeionosoma, Thunnus tonggol and Katsuwonus pelamis were low value in tuna. The tuna resources is rich in South China Sea,and it has not been effective development and utilization. With our emphasis on the South China Sea tuna fisheries, the tuna production increased year by year. However, the products are mainly marketing fresh and lacking deep processing technology, which caused low efficiency of resource utilization and low economic benefit.Therefore, Auxis tapeionosoma, Thunnus tonggol and Katsuwonus pelamis were used as raw material in this paper, essential nutrients in ordinary muscle, dark muscle, head and viscera were analyzed.The content of anserine and carnosine of differnt parts in three tuna be analyzed by HPLC. The ordinary meat, dark meat were hydrolyzed to cotain its protein hydrolyzates. Nutritional value and in vivo anti-fatigue activity of hydrolyzates were evaluated, respectively. In order to provide theoretical basis for further exploitation and improving value of the tuna resources in the South China Sea. The results of the research are as follows:(1) Different tissues of Auxis tapeionosoma, Thunnus tonggol, Katsuwonus pelamis are rich in protein. The protein content(in dry basis) of ordinary meat is highest(were 85.29%, 87.72%, 84.11%, respectively), followed by dark meat(were 75.34%, 81.07%, 75.35, respectively), the head(were 69.27%, 71.28%, 69.39%, respectively) and visceral(were 70.57%, 71.35%, 67.67%, respectively) were the lowest. The fat content(dry basis) were aranging from more to less as follows:the visceral(21.05%, and 18.26%, 22.72%, respectively), the head(17.42 %, 15.16%, 16.04%, respectively), the dark meat(9.38%, 7.38%, 10.26%, respectively), the ordinary muscle(6.5%, 2%, 4.94%, respectively). In addition to the visceral of Thunnus tonggl first limiting amino acid was sulfur-containing amino acids, the other parts of the three kinds of tuna were valine. The amino acid score(AAS) of different parts of Auxis tapeionosoma and Thunnus tonggol were greater than 90. The AAS of the ordinary meat and the dark meat from Katsuwonus pelamis were greater than 90. The lower score were the head and visceral from Katsuwonus pelamis were 86 and 75.3. The content of poly-unsaturated fatty acids such as DHA,EPA are rich and the mineral elements which beneficial to human body such as calcium, iron and zinc were abundant in three tuna.(2) HPLC conditions to detection of carnosine, anserine as follow: The Column: waters Xbridge BEH C18, the flow rate :0.7mL / min, the column temperature was 30 ℃, methanol: KH2PO4=90:10, pH =9.5. The content of carnosine and anserine in beef, chicken drumstick and chicken breast are all similar to values reported in the literature. But may be due to carnosinase,. In different tissues of three tuna, only the ordinary muscle of three tuna was detected a few anserine(0.252mg/g of Thunnus tonggol, 0.229mg/g of Auxis tapeionosoma, 0.154mg/g of Katsuwonus pelamis), and carnosine were not detective in other tissues. It is less than the content of other reported.(3) The nitrogen recovery of odinary muscle enzymatic liquid and dark meat enzymatic liquid from Auxis tapeionosoma were 71.06%, 69.36%, amino nitrogen content was 0.24mg/100 mL, 0.26mg/100 m L, respectly. The AAS of ordinary muscle hydrolysate podwer(OMHP) and dark muscle hydrolysates powder(DMHP) were 77 and 85 respectively, the content of total amino acids were 57.06 g / 100 g and 58.9g / 100 g, respectively. And the branched acid(related anti-fatigue) reached about 18%. The free amino acids of OMHP and DMHP were 22.40%, 23.49% of the total amino acid, respectively. Peptide content was 44.28g/100 g of OMHP and 45.07g/100 g of DMHP, which the peptides has the molecular weight below 5000 Da were both reached 70%, below 700 Da were 20%.(4) Compared with the control group, the OMHP and DMHP could significantly(p<0.05) prolong the swimming time of mice, reduce the consumption of liver glycogen and. decrease the content of serum urea nitrogen. It showed that both of the Enzymatic hydrolysis have anti-fatigue activity. And there is no difference in anti-fatigue activity of two kinds Enzymatic hydrolysis.