The Optimization Technology And Activity Of High Fischer Ratio Oligo-peptide From Tuna Meat

Tuna is a kind of deep-sea fish which has high nutritive and edible value. Tuna meataccounting for11%of the total weigh was regarded as fish meal with low efficiencyutilization during the process. However, tuna meat is nutritious as well as tuna. There is noeffective high-value utilization technology.High Fischer Ratio Oligo-peptide is a kind of mixture physiological active peptideconsisting of2~9amino acids. Hydrolysates containing peptides with a high ratio ofbranched-chain amino acids(BLAA) to aromatic amino acids(AAA), referred to as Fischerratio, It is defined as High Fischer Ratio Oligo-peptide when Fischer ratio is higher than20.Relevant experiments show that it has the function of relief hepatic encephalopathysymptom, anti-drunken, sobering-up, anti-fatigue and so on.This paper mostly study specefic aspects as follow:The preparation of High Fischer Ratio Oligo-peptide from the hydrolysis of tuna meatby two-step enzymes was studied. The optimal conditions were based on response surfacemethodology. Hydrolysates derived from tuna meat were static adsorbed by activatedcarbon in order to remove liberated aromatic amino acids (AAA) and purified by achromatography column filled with SephadexG-25gel. The distribution of molecularweight of the High Fisher Ratio Oligo-peptide was also determined by gel filtrationchromatography (SephadexG-25) as well. The results showed that the optimumenzymolysis conditions selected by Design-expert7.0were as follows: pepsin was selectedas the first enzyme, ratio of enzyme to substrate650U/g, ratio of tuna meat to water1:7(g/mL), temperture35.9℃; flavourzyme was selected as the second enzyme, ratio ofenzyme to substrate50700U/g, pH6.51, temperature51℃. The optimal absorptioncondition by activated carbon was ratio of activated carbon to water1:20(g/mL),temperature35℃, time3h. Then the fisher values of the two High Fisher RatioOligo-peptides (removing AAA) determined on Automatic Amino Acid Analyzer werecalculated to be37.52and32.08.The function of anti-drunken, sobering-up and anti-fatigue of High Fischer RatioOligo-peptide was evaluated by stomach perfusion to mice with different concentrations.The results showed that High Fischer Ratio Oligo-peptide can significantly prolong time ofthe loss of righting reflex and shorten time to sober up, increase liver glucogen contents andlower blood urea nitrogen levels and blood lactate levels after mice have exercised. Two active peptide fractions were purified by reversed-phase high performance liquidchromatography (RP-HPLC) and sequenced by de novo. The results of purification were inaccordance with the requirement of High Fischer Ratio Oligo-peptide. There were in totalof five peptides identified from two fractions, including one is a seven peptide, one is fivepeptide and three six peptides.