| Chilled and re-frozen method were two ways to storage food.Chicken breast plays an important role in common life.Freezing and thawing process itself will have a negative impact on the quality of the structure of the meat which causing the price difference.The impedance characteristics of biological tissue due to its cellular structure of the organization is closely related to fresh and thawed chicken breast.In this research,the discriminant accuracy under different conditions is studied.The paper studies breast impedance method based on the best test conditions and the samples are stored in chilled(4 ?)and different frozen storage time and the impedance magnitude.By measuring phase angle,frequency and quality of different freezing and thawing of frozen chicken breast,the study detected on the relationship between various parameters and impedance characteristics in order to discriminate the cold fresh meat from thawing analysis.The results represent that the accuracy of determining based on the impedance detection technology has great potential for rapid non-destructive testing of chilled meat reconciliation.1.Optimal test environment of impedance tester T2827AThrough the detection of electrode material(copper and graphite)during the test impact on the results of impedance measurement,the electrode arrangement(row of six rings and two needle)electrode and the muscle fiber arrangement(vertical and horizontal),the test voltage(100mv,500mv,1V,1.5V and 3V)and test environment temperature(4 ?,25 ? and 35 ?).Experimental results show that the method by controlling the variable stars,chicken breast impedance measurement process was really influenced by the five factors,frozen by the cold meat reconciliation test results are consistent.Utilizing copper electrodes were smaller,the use of two rows of six pin circular coefficient of variation of the probe,by the current flow of the muscle fibers perpendicular to the probe is less than the coefficient of variation of the parallel probe,and the best temperature was at 25 ?,500mv voltage less than the coefficient data within the same group of other parameter.In addition,according to the coefficient of variation that is the difference between the standard rate law,coefficient of variation,the higher the data and the system is stable shape,the result is more accurate.Therefore,the final result of the test conditions is at room temperature 25 ?,through the use of six needle probe,under 500mv test voltage of chicken breast measurements,and the current flow of the muscle fibers was in the position of perpendicular measurements.2.The determination of the minimum time of frozen-thawed processIn order to explore the thawing chicken breast that can be used to detect the minimum time by using T2827A which is also could be called the frozen and freeze-thaw distinguish cold fresh meat shortest time.The study compared the quality of the meat cold meat with frozen and thawed once and impedance magnitude and phase angle status as well.The results showed that:in the test range from 50Hz to 200kHz,impedance magnitude decreases as the frequency increases and the phase angle is reduced as the frequency increases(negative sign for angle direction),while the storage time changed,with the impedance magnitude increases the number of days began to decrease,and the longer the time is,the more reduced the amplitude significantly(P<0.05),the phase angle,too.On the sixth day,the phase angle and amplitude of any significant decreasing trend(P<0.05).With the increase of time,thaw loss,cooking loss,pressure loss,TBARS and shear forces have increased(P<0.05),the red value(a*)after first increased and then decreased,pH did not change significantly(P>0.05),amplitude and phase angle function value on the use of quality changes and the existing formulas obtained indicate that on the sixth day is the difference between freezing cold and fresh shortest time,and it has been verified and applied in subsequent trials.3.Effects of the the different thawed conditions for the chicken meat on the distinguish fresh from the frozen-thawedThe freezing process is mainly affected by time and temperature.In order to explore the difference between meat thawed frozen under different conditions determination result including temperature factors(-10,-18,-30)and time(30 days,60 days,90 days).When in a control variable,the determining the level of the effect depends on the length of the temperature or time could be done.Using the same measurement criteria and indicators and the usage of radial basis artificial neural network(LVQNN)and partial least squares determination method(PLS-DA)obtained accurately determine the optimal rate and compare results measurement method.The results showed that the temperature may be greater than the impact on the determination of the time,PLS-DA accuracy higher than LVQNN,which provides a new method for the detection of cold fresh and freeze-thaw.4.Research of the distinguish fresh from the frozen-thawed meat with the different conditions and the research of the reasons for the changes of the impedance changesObtained from the above research,the temperature is greater than the influence of frozen storage time.The frozen sample thawing temperature changes combined with changes in the frozen-thawed cycles and found that it could be got the higher correction rate by using PLSDA.The cold meat is up to 99%accuracy rate of discrimination and sample different temperatures and different thawing frozen cycles also have a higher accurate,mostly above 80%,which indicated that it might be the better accuracy rate of discrimination.For complex frozen samples,further research should be done to enhance the accuracy.Meanwhile,by measuring the quality of the sample configuration properties,microstructure,determination of potential exudate poor indicators,we found that impedance change of the different samples might be resulted from its internal structure and is closely related to changes in charged ions which can be interpreted as a change in impedance causes. |
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