Physicochemical properties as indicators of sensory characteristics of jidori and broiler chicken meat.

To improve the eating quality of chicken, the physicochemical properties were examined, which serve as indicators for breeding. Thigh meat was collected from 384 chickens from seven and nine types of the jidori (free-range local traditional pedigree chickens) or broiler chickens, respectively. The principal component analysis of the physicochemical values of the jidori and broilers were arranged as different groups in the score plot. The results of multiple regression analysis of the sensory characteristics and physicochemical properties of thigh meat indicated that the tenderness decreased with the higher crude protein content and cooking loss in the jidori and increased with lower cooking loss and higher moisture and ether extract content in the broiler. The juiciness of the jidori decreased as the moisture content decreased, and that of the broiler decreased as the cooking loss and crude protein content increased. The umami of both the jidori and broiler was improved by increasing the 5'-inosinic acid content. Therefore, it was suggested that the physicochemical properties, which serve as indicators of the eating quality of chicken, differed between the jidori and broiler, and that the general biochemical components, cooking loss and 5'-inosinic acid content may serve as breeding indicators.

Relationship between refractive index and fatty acid composition by gas chromatography and near-infrared fiber-optic method in bovine fat.

The causes of the difference in fatty acid composition between gas chromatography (GC) and near-infrared fiber-optic method (NIR) in bovine fat and their countermeasures were studied using absolute values of refractive index. Using intermuscular fat from 45 crossbreeds, refractive index was measured by using a refractometer, and saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) were measured by NIR and GC. The correlation coefficients between GC and NIR in SFA and MUFA, as well as those between refractive index and GC or NIR (in SFA and MUFA), were all greater than or equal to 0.8 (p < 0.01). In samples with 3% or more difference between GC and NIR in SFA and MUFA, GC and NIR values were often located in opposite directions to the regression lines with regard to refractive index. GC reanalysis on these samples slightly increased the correlation coefficient between GC and refractive index and reduced the difference between GC and NIR by 1%-2%. Results indicate that measurement errors in GC and NIR are related to their more than 3% difference, and GC reanalysis based on refractive index may improve its accuracy.

Effect of dietary kapok oil supplementation on growth performance, carcass traits, meat quality and sensory traits of pork in finishing-pigs.

Kapok seed and oil from the tropical zone are widely used as pig feed to harden porcine fat in Japan. This study evaluated the effect of dietary kapok oil supplementation on pork quality and sensory traits. Five Duroc pigs each were assigned to an experimental group supplemented with kapok oil and a control group. Dietary kapok oil supplementation had no effect on growth performance and intramuscular fat content in the Longissimus dorsi muscle (LM). Supplemental kapok oil increased saturated fatty acid contents in subcutaneous and intramuscular fat and decreased monounsaturated fatty acid levels (P < 0.05). Off-flavor detection by a trained panel was higher in the experimental than the control group (P < 0.05), but tenderness, juiciness, texture and flavor intensity of LM chops were similar in both groups. The overall palatability of pork as judged by a consumer panel decreased with kapok oil supplementation (P < 0.01). These results indicate that while growth performance, intramuscular fat contents and carcass characteristics were unchanged, while dietary kapok oil supplementation makes firm fat to prevent inferior soft fat in pork, it can lower the palatability of pork due to a decrease in monounsaturated fatty acids.

Effects of dietary lysine/protein ratio and fat levels on growth performance and meat quality of finishing pigs.

This study aimed to evaluate the effects of dietary lysine/protein ratio and fat levels on the growth, carcass characteristics and meat quality of finishing pigs fed feed made from food waste, including noodles and chocolate. Four dietary treatments, 2 levels of lysine/protein ratio (0.035 and 0.046) and 2 levels of fat (3.3% and 6.0%), were adapted to a 2 × 2 factorial arrangement. Each diet for the finishing pigs contained the same levels of adequate crude protein (16%) and lysine (0.58-0.75%), and similar levels of high total digestible nutrients (90.2-92.6%). In total, 32 LWD pigs with an average body weight of 57.2 kg were assigned to 4 dietary groups. The pigs were slaughtered at about 115 kg. Growth performance was not influenced by the dietary treatments. Carcass characteristics were slightly influenced by the dietary fat level. As the dietary lysine/protein ratio decreased, the marbling score of Longissimus dorsi muscle increased and the intramuscular fat (IMF) increased from 6.82% to 9.46%. Marbling score was not significantly influenced by the dietary fat level. These results indicate that IMF increased without adverse effects on growth, carcass characteristics and meat quality, when pigs were fed a diet with low lysine/protein ratio.