| 5'-Inosinic acid (IMP) is the major umami compound in the meat of livestock, poultry and fish, having the important function to the meat flavor formation. This thesis studied the analytical method of IMP in meat of chicken, the deposition of IMP in chicken muscle, the effect of methods of storage and processing, and the effect of feeding conditions on amounts of IMP in chicken meat. The aim was to provide basic information for improving poultry meat flavor by the way of nutrition modification. Study on the analytical method of IMP and its related nucleotide acidsWe investigated the HPLC analysis of IMP and its related nucleotide acids and the extraction method of the above nucleotide acids in chicken meat in this experiment. The results were as follows: Using 0.05M phosphate buffer (pH6.8) and methanol (92/8,v:v) as the mobile phase was the best condition. IMP in chicken meat extracted with 5% PCA is the best method.Study on the deposition of IMP in chicken muscleThe deposition of IMP in muscle of Beijing fatty chicken, Jingxing yellow chicken100 and AA broiler was studied in this experiment. The results were as follows: Concentrations of IMP in breast and thigh meat of the above strains increased with age. Concentrations of IMP in breast and thigh meat of AA broiler were significantly higher at 8w and 13w than 4w (P<0.01), and Jingxing yellow chickenlOO changed in accordance with the AA broiler. Content of IMP in breast and thigh meat of Beijing fatty chicken was significantly higher at 8w than 4w (P<0.01), and 13w was significantly higher than 8w (P<0.05). Concentrations of IMP in breast meat were significantly higher than that of thigh meat (P<0.01). Contents of IMP in breast meat of Beijing fatty chicken and Jingxing yellow chickenlOO were significantly higher than that of AA Broiler at 8w and 13w. Factors affecting the content of IMP were the content of precursors of IMP and the activities of IMP-degrading enzymes. Effects of storage on the content of IMP in chicken meatChanges of content of IMP in breast meat of Jingxing yellow chickenlOO stored at differenttemperatures for different time were investigated in this experiment. The results were as follows: thecontent of IMP reached the peak at 2h postmortem in raw meat, and decreased gradually in furtherstorage. IMP degraded fast at 23-25 C, and decreased to only 38.11% amount of the maximum after 24h(p<0.01) ; the content of IMP in meat stored at 4 C decreased significantly from 2d postmortem(p<0.05), and reached to only 45.5% of the maximum at 7d postmortem ; the content of IMP stored at-18 C didn't decreased distinctly after 60d. IMP in cooked meat didn't significantly degrade at 20-25 Cfor 24h, 4 C for 5d and -18 C for 90d. The activities of IMP-degrading enzymes were the major factoraffecting the stability of IMP in raw and cooked meat during storage.Effects of processing on the content of IMP in chicken meatChanges of content of IMP in breast meat of Jingxing yellow chickenlOO processed in different Methods were investigated in this experiment. The results were as follows: Content of IMP decreasedsignificantly in meat processed by all kinds of method (p<0.01) , and further decreased with heat time prolong. The content of IMP in meat heated at 75 C was significantly higher than that heated at 95 C (p<0.05) .Among 4 kinds of high temperature, the content of IMP in meat processed by microwave was highest compared with those of meat processed by other methods (p<0.01) , the content of IMP in fried meat was significantly higher than that of roasted meat (p<0.05) , and the content of IMP in meat processed by 121 C high pressure was significantly lower than others. The activities of IMP-degrading enzymes were inactivated severely after all kinds of process, especially at temperature above 95 C.Study on the umami intensity of meat of different chicken speciesSensory umami intensity of meat and broth of AA broiler, Jingxing yellow chicken, and Beijing fatty chickens were investigated in this experiment, aiming at inquiring the ef... |
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