Study On The Controlled Freezing-point Aging Technique Of Chicken And Fillet

Controlled freezing-point Storage can be used to store agricultural products, aquatic products et al, keep the freshness. it become one of the best preservation technology, not only to extend the ice temperature food preservation period and shelf-life, but also to accelerate the maturity of biological material, improve its flavor, it has a wide range of applications, but in general is only study on the ice temperature storage of food, and less on the food quantitative analysis of ice temperature and taste components of after the freezing-point ripened, no researchers have in-depth study on this, based on this, a comprehensive analysis of several food through the ice temperature in the ripening process of sensory evaluation, pH, volatile basic nitrogen (TVBN ), the total number of bacteria freshness index changes, and to determine the shelf life of food, while the innovation is that verify the shelf life by some important indexes, such as amino acids, nucleotides and other components, which were analyzed quantitatively and compared kinds of indicators in the different temperature conditions ; by high performance liquid chromatography (HPLC ) analysis of the different maturity periods, respectively, of the chicken, fillet samples of amino acids, nucleotides, amino acid changes and cold acclimation on the impact of changes to the freezing-point ripening, so as to provide a reference on the production and application.Four experimental parts are included in this article, and they are as follows: The first part is to determine the shelf life of fresh, frozen by comparing the freezing-point during the mild, chicken, blue fillet pH, TVB-N, total number of bacteria, changes in sensory index to infer the level of freshness shelf period at the first level of freshness; The second part is the study of the quality changes in the of chicken and fillet under the freezing-point storage at the first level of freshness, test free amino acids generated of the two different storage methods and comparative analysis of two storage methods of free amino acids during the storage of total acid, essential amino acid, glutamic acid content of change; The third part is experimental research on the freezing-point ripening of chicken, determination of the different stages of chicken freezing point ripening, detection of the amino acid and nucleotide in chicken samples in different stages of ripening , the amino acid of the test sample by low-temperature acclimation and different composition of chicken in ripening; The last part is experimental research on the freezing-point ripening of fillet, determination of the different stages of fillet freezing-point ripening, detection of the amino acid and nucleotide in chicken samples in different stages of ripening , the amino acid of the test sample by low-temperature acclimation. The main conclusions are as follows:1. The pH, bacterial count, volatile basic nitrogen (TVBN ) and sensory evaluation of chicken and fillet at room temperature, refrigeration and freezing of three conditions has a good correlation, could be used as the important indicators of quality and shelf-life evaluation of chicken and fillet. Therefore, according to various indicators of the sample inferred from its shelf-life, extrapolated shelf life of refrigeration and freezing-point storage of chicken and fillet are 11d, 8d and 23d, 20d.2. The freezing-point storage of Chicken and fillet, are not only a long storage period, maintain the freshness of the sample, but also generate more amino acid in a fresh shelf life. At the freezing-point storage, the total free amino acids, essential amino acid, glutamic acid absolutely and relatively increase in the amount of volume was significantly higher than the increase in the amount of under refrigeration. In addition, amino acid increment of fillet is significantly different from chicken increment result from the more protein content of fillet meat, so its storage and ripening time was less than that of chicken.3. The content of free amino acid in different stages of ripening have different levels of increase, in 11 days, free amino acids increased as ripening time increasing significantly, but the rate of increase was smaller and smaller, 11 days later, only slightly more than the amino acid content of that day. The content change of nucleotide at different stages of ripening is same as free amino acid content confirmed that the IMP has a synergistic effect with some flavor amino acid. Ripened by the means of gradient cooling process low temperature acclimated from 6℃down to -0.8±0.2℃, its amino acid content was significantly higher than the direct freezing-point and cooling from 6℃to -0.8±0.2℃at the rate of 1℃/ 2h. by 24h freezing-point ripening, content of free amino acid of chicken breast meat was significantly higher than that of chicken thigh meat, especially the taste of amino acid Glu, Ser, Gly, Thr, Ala, Pro and Arg, His and so on.4. The IMP and GMP content of fillet changes at the freezing-point ripening process, were consistent with the free amino acids, the results of the two mentioned in the literature is consistent with a synergistic effect. Ripened by the means of gradient cooling process low temperature acclimated from 6℃down to -1.4±0.2℃, its amino acid content was significantly higher than the direct freezing-point and cooling from 6℃to -1.4±0.2℃at the rate of 1℃/ 2h. The difference with the chicken is that most of nucleotides are significantly more than that of the chicken except that the IMP is slightly smaller than the other chicken samples, the amino acid content of the freezing-point ripening process also increase faster, it reflects the reason that the ripening of fillet is shorter than poultry.