2.4.4 Sensory evaluation
Category scaling method was used in this study. Meat samples were categorized with regard to color, flavor, tenderness, juiciness and overall acceptability of an eight-point category scale (Griffin et al., 1992 and Dawkins et al., 2000). The frozen samples were thawed overnight at 4 °C then each sample was wrapped in an aluminum foil and cooked in an oven at 163 °C for 90 min (Griffin et al., 1985). Then the meat samples were cut into small pieces of about one square inch and given a random code number that remained in every session. Then they were randomly presented warm on numbered plates to be tasted. Forty untrained panelists were asked to assign a category to each meat sample of the three treatments and the average of the panel assessments was taken to define the characteristic of the sample. The panelists were requested to put off food and smoking two hours before tasting. Water at room temperature was available to remove the remaining flavor of the previous samples. Taste panel events were carried out in the panel room in Faculty of Food Science and Technology, UPM.
2.5 Lipid oxidation
Thiobarbituric acid reactive substances (TBARS) method was used for measuring lipid oxidation. Samples of LT muscle for different ageing period (1-day and 7-day) were assessed using the QuantiChrom™ TBARS Assay Kit (DTBA-100 BioAssay Systems, USA) according to manufacturer’s protocol.
2.6 Statistical analysis
Data sets of fatty acid composition were subjected to one-way analysis of variance using the GLM procedure of SAS version 9.1 (SAS, 2003). For meat quality and lipid oxidation variables tow-way analysis of variance was used (diets X post mortem aging periods). Data set of sensory evaluation was analyzed with the Kruskal Wallis procedure (non-parametric one-way ANOVA). Least-square means were computed and tested for differences by Duncan multiple range test. Differences between least squared means were considered to be significant at p < 0.05. Data were presented as least-square means ± standard errors.