[Measurement of cooking loss and tenderness of fresh pork using visible/near infrared spectroscopy].

Cooking loss and tenderness are important quality characteristics of fresh pork. To find a rapid, non-destructive and non-contaminated method to measure them, visible/near infrared spectroscopy was proposed for measurement of cooking loss and tenderness of vacuum-packed pork loin. The acquired raw spectra were pretreated by Savisky-Golay smoothing, second derivative and MSC, respectively using the software of Unscrambler 9.6. A total of 104 samples were used in the experiment. The samples were divided into calibration set and validation set. The calibration set was used to set up calibration model and then the model was adopted to predict the samples of validation set. The partial least square regression (PLSR) was used to build calibration model. The results show that the correlation coefficient for cooking loss and shear force are 0.81 and 0.78 respectively. It is feasible and effective that measure cooking loss and shear force of vacuum-packed fresh pork loin using visible/near infrared spectroscopy in interactance mode.

[Detection of fatty acid composition in intramuscular fat of packed pork loin by near infrared spectroscopy].

Near infrared spectroscopy as a new method was proposed for rapid and non-destructive measurement of fatty acid composition in intramuscular fat of packed pork loin. Gas chromatography was used as a reference method for the spectral analysis of fatty acid composition. The fiber optic in interactance mode was adopted to measure the spectra of packed pork loins by low density polythene. The original spectra were pretreated by smoothing and 2nd derivative, and then PLS calibration model was builtby using software of Unscrambler 9.6. A total of eighty two samples were used in the experiment. The samples were divided into calibration set and validation set after removing the outliers. The calibration set was used to set up calibration model and then the model was adopted to predict the samples of validation set. The results show that the correlation coefficient for C14 : 0, C15 : 1, C16 : 0, C16 : 1, C18 : 0, C18 : 1, C18 : 2, C18 : 3, C20 : 1, C20 : 4, SFA, MUFA, PUFA is 0.57, 0.76, 0.71, 0.77, 0.62, 0.81, 0.86, 0.91, 0.85, 0.91, 0.67, 0.81 and 0.95, respectively. It means that evaluating fatty acid using near infrared spectroscopy in interactance mode has higher precision. Near infrared spectroscopy technique is a feasible and rapid method for nondestructive detection of fatty acid composition in intramuscular fat of packed pork loin.

[Prediction of water holding capacity of fresh pork using near infrared spectroscopy].

Water holding capacity (WHC) is an important quality characteristic of fresh pork. It is necessary to determinate it by a rapid and nondestructive method in order to reduce the loss of meat. Near infrared spectroscopy as a new method was proposed for rapid and nondestructive measurement of WHC of vacuum-packed pork loin. Two reference methods for measuring water holding capacity were used to evaluate the water holding capacity, i. e. drip loss and press method. The acquired raw spectra were pretreated by Savisky-Golay smoothing and second derivative, respectively. A total of 106 samples were used in the experiment. The samples were divided into calibration set and validation set. The calibration set was used to set up calibration model and then the model was adopted to predict the samples of validation set. The partial least square regression (PLSR) was used to build calibration model. The results show that the correlation coefficient for drip loss and press method is 0.74-0.79. It shows that evaluating the water holding capacity of vacuum-packed fresh pork loin using near infrared spectroscopy in diffuse reflection mode is better than those results with reflectance or transmission.