Electronic Nose for Measurement of Freshness Change of Chilled Pork during Storage at Different Temperatures

Electronic nose was used to measure the freshness change of chilled pork during storage at-18,0,4,10 or 20 ℃.Injection volume of minced samples was optimized to be 1500 μL.Principal component analysis(PCA) of volatile odor of chilled pork was conducted.Electronic nose output signal was plotted as a function of storage time to estimate shelf-life of chilled pork stored at different temperatures.Partial least squares regression(PLS-regression) was employed to analyze correlation between electronic nose output signal and sensory evaluation score of volatile odor of chilled pork stored at 4 or 20 ℃.Results showed that there was a significant difference in volatile odor of chilled pork stored for different time at-18,0,4,10 or 20 ℃.Higher storage temperature resulted in earlier occurrence of significant decrease of freshness.The shelf-life of chilled pork stored at the above temperatures was 336,180,72,48 h and 18 h,respectively.The correlation coefficients between electronic nose output signal and sensory evaluation score of volatile odor of chilled pork stored at 4 and 20 ℃ were as high as 0.9982 and 0.9998,respectively,demonstrating that electronic nose is a reliable alternative to sensory evaluation for analysis of volatile odor of chilled pork.Electronic nose sensors TA/2,T40/1,T40/2,P30/2,P40/1,P10/2 and P10/1 were all found to give excellent specific responses to various characteristic odors of pork.