Study On Properties Of Freezing-Point Storage And Quality Kinetic During Storage For Chicken Breast

The fresh breast meat from chicken was selected in this test. Based on thetheories of food chemistry, microbiology, etc, the differences of storage among roomtemperature storage, cold storage, frozen storage and tea polyphenols （TP） withfreezing-point storage were analyzed. The quality indices were determined underdifferent storage condition to eastablish quality kinetic equation and to foreast theshelf of chicken breasts. The main results were described as following:1. The content of water, protein, fat, soluble solid and ash in fresh chicken breastwas75.31%,16.82%,2.31%,3.21%, and1.32%, respectively. The freezing point offresh chicken breasts was-1.5℃. The medium agent added, such as salt and sucrose,can expand the scope of the freezing point, and then the content of water in muscledecreased, the content of soluble solid raised. The four factors including saltconcentration （X₁,%）, sucrose concentration （X₂,%）, water concentration （X₃,%）,and soluble solid concentration （X4,%） at the freezing point （Y,℃）were disposed bylinear regression analysis, and the relevant equation was obtained:Y=-14.98-0.553X₁+0.234X₂+0.169X₃+0.233X4Salt concentration at the freezing point was significantly different （p<0.01）through stepwise regression analysis and significance analysis. The regressionequation was analysed again and got following equation: Y=-1.56-0.375X₁. Theequation was significant （P<0.05） by significance test, it showed that this equationcan well express salt concentration at the freezing point of chicken breasts.2. The physical and chemical indices of chicken breasts storaged at differenttemperature were analysed on a regular way. The storage effect was in turn frozenstorage （-18℃）, ice temperature storage （-1.5℃）, cold storage （4℃）,room temperaturestorage （15℃）, respectively. The breast went bad after3days in15℃and5days in4℃. However, it could inhibit the microbial activity and extend the freshness andshelf life of chicken breasts under-1.5℃and-18℃storage conditions. The reliablepreservation time was10days for-1.5℃, and15days for-18℃, respectively.3. The change of total plate count and TVB-N values on the first chemical reactionand Arrhenius （Arrhneius） equation showed the better fitting and accuracy when theregress equation was applied. At the same time the activation energy and regressionwere respectively obtained54361.09J/mol （Ea） and1.23×10⁹（k₀） for total number ofbacteria, and56217.61J/mol （Ea） and4.68×10⁹（k₀） for TVB-N value. Taken the total number of bacteria106cfu/g and TVB-N value15mg/100g as the end of shelf life, theshelf life of breast stored at15℃,4℃,-1.5℃,-18℃were respectively1.98d,5.04d,8.24d,39.13d.4. The fresh breast were stored at ice point （-1.5℃）after immersed in0.01%,0.03%,0.05%,0.07%of TP solution. The physical and chemical indices analysedshowed that TP had a certain effect during the preservation. There are to some extentmany beneficial effect through this process, such as controling the growth ofmicroorganisms, prolonging the length for preservation, improving nutritional value,extending shelf life. Comparison with the control group,0.05%TP treatment groupwith ice temperature storage is better than the others, following by0.07%,0.03%,0.01%TP group with the ice temperature.5. The18fatty acids in chicken breast were identified by using GC-MS. There arenine saturated fatty acids,37.39%of total fatty acids： nine unsaturated fatty acids,62.51%of total fatty acids. For the unsaturated fatty acids, the monounsaturated wastaken4species,42.77%of total fatty acids, the polyunsaturated occupied5species,19.74%of total fatty acids. The unsaturated fatty acids were1.68times as much assaturated fatty acid.6. The fresh breast was stored at freezing point for10days after immersed in0.01%,0.03%,0.05%,0.07%concentration of TP. The content of18kinds of fattyacids decreased to a certain extent in control group and treatment groups. All TPgroups inhibited loss of fatty acids, the best result was0.07%TP group.