Study On The Change Of Taste Compounds During The Process And Storage In The Stewed Duck

The stewed duck which is welcomed in Chinese’s people is a traditional Chinese meat product. For transforming traditional process experience of the stewed duck into the theory, and realizing the standard industrial production of the stewed duck, in this paper, the change role of the main taste compounds during the process and storage of the stewed duck and the effect of critical process on the taste compounds of stewed duck were studied. On the basis of both studies, a preliminary study on the formation mechanism of taste of the stewed duck was given. According to this experiment, a quality control system during the productive process of the stewed duck was established and expected to provide a theoretical and scientific basis for high quality and industrial production of the stewed duck. Results were summarized as follows:1. Study on the determination method of taste nucleotides in stewed duck by high performance liquid chromatographic (HPLC)Taste nucleotide composition and contents of the stewed duck were analyzed by HPLC method. Compared with the effect of different mobile phase and chromatography column on the separation of nucleotides and degradation products in the stewed duck, the results showed that a single mobile phase could not simultaneous separate of six nucleotides and degradation products in the stewed duck, and obtained the optimum chromatographic conditions:GMP, Hx, AMP and HxR were determined by HPLC using LiChroCART C180.05mol/L K2HPO4(pH4.33) and methanol as mobile phase, and ADP and IMP were determined by HPLC using LiChroCART C18,0.5%phosphate and methanol as mobile phase.Contents of taste nucleotides in stewed duck were determined by HPLC. The results showed that the relative standard deviation of nucleotides in stewed duck was from0.24%to0.97%. The average spike recoveries of nucleotides were from97.09%to105.51%. This method could be applied to assay taste nucleotides and their degradation products in stewed meat products.2. Study on the change of taste compounds during the processing of the stewed duckThe change role of chief taste compounds in the stewed duck was analyzed by measuring the contents of free amino acid, oligopeptides, nucleotides and their related components in major process steps. The results showed that IMP and GMP, which determined the characteristics taste of the stewed duck, were the chief umami nucleotides, and are thus most likely to be the rease for the delicious taste of the stewed duck. The dry-curing process, which was the critical process, had a significant increase effect on the contents of taste compounds. The content of taste components increased significantly over time, reaching a maximum level of intensity at24h. In addition, the change of nucleotides during the dry-curing stage of the stewed duck showed that the conversion reaction among the nucleotides was consistent with the ATP degradation pathway. This preliminary study revealed the tast formation mechanism of the stewed duck. In the subsequent processing, the contents of free amino acids, IMP, GMP, Hx and HxR decreased significantly. The contents of Oligopeptides and ADP remained constantly, only the contents of AMP increased significantly. The option pH value and suitable content of salt were contributed to the taste of the stewed duck.3. Establishment of quality control system for the stewed duck in the productive processBasic principle and method of HACCP was used to analyze the potential hazard from biology and chemistry aspects, and Critical Control Points (CCP) was also determined during the productive process of the stewed duck. The results indicated that CCP included the procedure of cleaning, boiling, packing and sterilization. According to significant hazards, the table of HACCP plan was set up, the critical limit was set, the feasible and effective control measures and corrective measures were also adopted.4. Study on the change of taste compounds during the storage of the stewed duckIn order to understand the impact of different sterilization methods and storage temperature on the quality of the stewed duck during storage, The change role of chief taste compounds during the storage of the stewed duck, was analyzed by measuring the contents of the chief taste compounds and their related components in the stewed duck, which were treated with different methods of sterilization and stored at different temperature. The results showed that pasteurization could effective delay the change of the water and pH value, and has not a significant effect on the contents of oligopeptides and springness of the stewed duck. Pasteurization and high-pressure sterilization have a significant effect on the contents of nucleotides, free amino acids, protein, color, hardness and chewiness, but pasteurization was better than the high-pressure sterilization. Storage temperature has not a significant effect on taste compounds of the stewed duck, but low temperature (4℃) storage was better than room temperature storage (25℃).