STUDYING THE RELATIONSHIP BETWEEN PORK FRESHNESS INDEXES AND NEAR-INFRARED SPECTRA

27. 農業機械學刊第13 卷第4 期2004 年12 月. 豬肉鮮度指標與近紅外線光譜相關性之探討. 蕭介宗. 1. ，駱秋英. 2. ，陳力騏. 3. ，劉昌群. 4. ，洪淑玲. 5. ，蘇淑禎. 6. 1. 國立台灣大學生物產業機電工程學系教授，本文通訊作者Near infrared reflectance spectra on pork samples were analyzed and calibrated for the seven measured pork freshness indexes such as standard plate count, pH value, free primary amines, extract release volume, and intensities of green, blue, and red. If the relationship between spectra and the seven measured pork freshness indexeswas established by PLSRmodel, the calibration line could be used to predict the pork freshness with the advantages of saving time and zero-polluted environment. With 90 samples at 30℃ and 98 % relative humidity, the predicted allowable pork storage time is 9.45 hours determined by the fresh limit of 7.5 log CFU/g from the regression equation of standard plate count. These calibrated lines by PLSR showed that correlation coefficients between spectra and standard plate count, green intensity, pH value, and blue intensity were 0.80 (original spectra), 0.77 (original spectra), 0.71 (first difference spectra) and 0.71 (first difference spectra) respectively. For free primary amines, extract release volume and red intensity, the correlation coefficients of calibration lines were 0.61 (second difference spectra), 0.55 (second difference spectra), and 0.59 (original spectra) respectively. Consequently, the standard plate count among the above mentioned seven indexes was the best for predicting pork freshness