Evaluation method for firmness and stickiness of porcine perirenal fat

The firmness and stickiness of chilled porcine fat at 4°C were evaluated with an Instron compression tester and compared with fatty acid composition. Firmness of cylindrical adipose samples was measured at a force producing a 70% deformation. Firmness values were correlated with refractive index data (r=-0.67), melting point data (r=0.77), and saturated fatty acids concentration data (r=0.72) of the extracted lipid, and with sensory scores data (r=0.89). The firmness value correlated with the concentration of C18:0 (r=0.73). The stickiness of comminuted fat samples was evaluated with the Instron using a fixed load at a compression force of 20N and crosshead speed of 1.5mm/s. Single regression analyses showed that the stickiness parameters, stretch and adhesiveness correlated negatively with the concentration of the saturated fatty acids data (r=-0.64, -0.52) but positively and weakly with the monounsaturated fatty acids data (r=0.28, 0.34). Multiple regression analysis improved their relationships. These results indicate that mechanical evaluation may be used to predict porcine fat texture and saturated fatty acids concentration.