| In order to improve the flavor of oyster hydrolysates, the effect of hydrolysis onflavor of oyster was analyzed. The improvement of ginger and yeast on oysterhydrolysates flavour was studied. The technology of oyster sports beverage made ofenzymatic hydrolysis of oyster was researched, and the safety and antifatigue activitywas explored by animal experiments. The major work of this research was asfollowed:1The change of volatile components on oysters pre and post hydrolysis was analyzedaccording to sensory valuation, electronic nose, SPME-GC-MS (solid phasemicroextraction gas chromatography-mass spectrometry) and ROAV (relative odouractive value). The sensor value showed that fishy smell, bitter and rancidity wasenhanced, while the grassy was lightened. There were significantly differencebetween raw oyster and its hydrolysates, detected by electronic nose. Volatilecomponents were analyzed by SPME-GC-MS and identified by comparing their massspectra with NIST mass spectral database. The result showed the content of aldehydes,esters, furans after hydrolyzed were increased from23.54%,4.25%,14.43%to36.9%,8.46%,20.78%, respectively. While the content of ketone and alcohol decreased from21.72%,19.43%to14.2%,13.4%respectively. By calculating the relative odor activevalue, the main volatile components of raw oysters were1-octane-3-alcohol,2-Nonenal,2-ethyl furan,2,3-Octanedione, octanal which present grassy and fruity.However,2-Nonenal,3-Methylbutanal, Methylsulfide,1-octane-3-alcohol, octanal,Nonanal,2-ethyl furan which distributed fishy and rancidity were the main volatilecomponents of oyster hydrolysates. The content of3-Methylbutanal, Nonanal,2-Nonenal,3,5-Octadien-2-one which come from lipid oxidation were increased to5.09%,1.6%,1.3%,0.5%respectively. The result showed flavor deterioration wasrelated to lipid oxidation during hydrolysis.2.The effects of ginger juice on flavor improvement of oyster hydrolysates was studied. The result showed the hydrolyze efficiency of oysters had no change when2%ginger juice added. And the TBARS value of oyster hydrolysates was significantlydecreased. sensor value showed oysters hydrolysate with ginger juice had fewerfishy, rancidity and more fruity. The results of SPME-GC-MS and ROAV showed therelative content of lipid oxidation products such as Pentatal,3-methyl-Butanal,heptatal,(E)-2-Nonenal,(Z)-4-Heptenal and3,5-Octadien-2-one, which caused fishyand fatty ordor, were increased to5.09%，1.6%，1.3%，0.5%respectively. The foulsmell of the oyster protein hydrolysates might be mainly related to lipid oxidationduring hydrolysis. However, after addition of ginger juice, the unpleasant compoundsderived from fat oxidation such as Trans-2-Pentenal，Nonanal，(Z)-4-Heptenal，2,3-Octanedione were not detected. Meanwhile,the concentration of3-Methyl-Butanal, Hexanal, Trans-2-Hexenal were reduced by81.02%，33.28%and54.39%respectively. The main volatile components of gingers such as geraniol,citronellol, citral p-cymene and linalool were found in the hydrolysates and providedflowery, lemon and orange flavor for the hydrolysates. Therefore Ginger juice had asignificant contribution to the flavour improvement of oyster hydrolysates.The effects of yeast on flavor improvement of oyster hydrolysates were studied.The optimal condition for yeast treatment was as follows:0.2%wine yeast,fermentation temperature37℃,fermentation time30min. Compared with untreatedoyster hydrolysates, fermentative hydrolysates had pleasant flavor and rich fruity,flowery. Meanwhile, the fishy was undetected. Analyzed by SPME-GC-MS, thecontent of lipid oxidations such as2-Nonenal and3-Methylbutanal was decreased,while the content of2,3-Butanedione, Ethyl Octanoate,6-methyl-5-Hepten-2-one,Geraniol was increased to6.01%,0.42%,1.09%respectively,and become to be themain flavor competent. The change of amino acid composition before and after flavorimprovement was investigated. The content of amino acid was increased exceptL-Threonine, L-Serine, lysine and arginine. The content of total amino acids andessencial amino acid in hydrolysates was added to63.17%and27.30%, respectively.The nutrient component of oyster enzymatic hydrolyzates was determined. Thetotal sugar content of oyster enzymatic hydrolyzates was0.76%, protein content was 1.02%, content of taurine was0.2%. The content of essential amino acid in thecontents of total amino acids was43.22%. Similarly, rich trace elements and mineralswere contained in oyster enzymatic hydrolyzates. The content of calcium, ferric,aluminum, sodium, potassium, magnesium was39.76μg/mL,50.08μg/mL,2.72μg/mL,772.18μg/mL,267.44μg/mL,29.16μg/mL, respectively.The process technology of oyster sports beverage was studied. According to thenational standard of sports beverage formulation and the recipe of commercial sportsbeverage, the recipe of oyster sports beverage determined was as follows: the powderof oyster enzymatic hydrolyzates was2g in per100ml. The total sugar content was6%, the ratio of the content of glucose, sucrose, malt dextrin was4:1:1. The content ofsodium, potassium, vitamin B6, vitamin B12, vitamin C was40mg,10mg,0.3mg,1μg,4mg, respectively.The sterilization method of oyster sports beverage was determined. With color,taste, smell, vitamin C loss rate and colony forming unit as evaluation index, the beststerilization methods of oyster sports beverage were90℃,20min.3.Through using exhaustive swimming mouse model, safety and antifatigue activitywere evaluated. The results showed that oyster sports beverage was safely.Oystersport beverage prolonged the swimming time to exhaustion of mice compared to thecontrol. Taken30minutes before a workout, oyster sport beverage increased thelevels of muscle glucose and liver glycogen. It decreased the levels of lactic acid andMDA. But the content of blood urea nitrogen had no difference. Oyster sportsbeverage taked by mice after sports, the level of MDA and liver glycogen which hadsignificant difference with control backed to the normal state. However, the level oflactic, blood urea nitrogen and muscle glucose was significantly different fromnegative control. The result showed oyster can increase an endurance capacity butcannot facilitate recovery from fatigue. |
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