Study On Flavor Improving And Activity Of Tuna’s Nutrition Peptide

In this paper, the questions, fishy and bitterness in hydrolysis of protein, werestudied. We used the rim leftover of tuna as the experiment materials, and dried thetarget components, which were obtained by proteolysis and ultrafiltration. To archivethe effect of debittering and deodorization, we used the dried products as the materialsof plastein reaction and detected the bio-activities of the improved peptide with micegrowing and anti-oxidation test. The results were as following:1. The yield of peptide was13.81g with freeze-dried and14.55g with spray-dried. Thecolor of peptide was dim got by freeze-dried, some water left on the surface,and therewas heavy fishy smell; in comparion with freeze-dried, the color of peptide got byspray-dried was wheat, existed with form of power, less fishy smell left. Peptide gotwith two dried method had high hygroscopicity, and it could become sticky in theair.The functional difference was small between the two method.Compared with twomethods, freeze-dried had to refrigerate in the vacuum, the energy consumption ishigh, and the sample processed once is small, so it was not applied to industrialproduction, however spray-dried has the advances,such as short time,simpleinstallations,low cost and high yield, also the sample treatment is continuous.Considering with cost, yield, we choose spray-dried as the production method underthe condition of input temperature145℃,drying time65min and feed rate at3ml/min.2. Choosing the ratio of plastein and bitterness as the research index, the orthogonalexperience was done with substrate concentration, temperature, pH as theinvestigation factors. The optimized conditions for plastein reaction were: systempH5.0, substrate concentration40%(w/w), temperature32℃, under these conditions,the ration of plastein reaction could reach to58.93%, bitterness value was decreased to2.Through the evaluation of the three people group, the fishy smell of peptide waschanged greatly after plastein reaction, using electronic nose to detect the smell andanalyse the data, the response value of the2ndsensor decreased greatly, which issensitive to NO compounds, however the response value of other sensors increasedslightly, according to the analyse, we can know the fishy smell mainly composes with NO compounds.3. Using Gel-chromatography to separate and purify the peptide solutions, resultsshowed that there were three peaks A,B,C when the peptide solutions flowed throughsepadex-G25, and the area of Peak B was the largest one, the45thtube had themaximum absorbance value at280nm.use SDS-PAGE gel electrophoresis todetermine the molecular weight of purified peptide and plastein, the results were: themolecular weight of peptide and plastein was distribution between2000Da and5000Da, and the latter’s molecular weight was more than the former one, it showedthat there was new substance generated during the plastein reaction.4. Studied the effection of peptide to mice growth status, the everage of mice weighthad increased greatly, compared with control group, however the everage length ofdifferent group mice was not obvious in seven feed cycle. Dissect the mouse afterfinishing feeding,the mouse spleen of the experience group was much heavier than thecontrol group,other viscera in experience group was much similar with the controlgroup.Results showed that:peptide obtained from tuna fish had the efficacy of growthand immunity.