• Asian-Australasian Journal of Animal Sciences
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• v.21 no.8
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• pp.1201-1206
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• 2008

The effects of free-range farming, compared to a conventional production system, on carcass and meat qualities were studied using black-feathered Taiwan native chickens. Twenty 16-week old females were purchased separately from a free-range farm and a conventional production farm and used for this study. The results showed similarities in the live weight (roughly 2.1 kg), dressing percentage (69%) and meat percentage (19%) of deboned leg quarter. Significant differences (p<0.05) found for the free-range chickens included: a higher percentage of meat for the breast, an increased crude protein content and chewiness value for the breast, but decreased crude fat content and lower hardness and fracturablility values for the leg quarter. Significantly higher L* values were found for the breast and leg meat of conventionally produced chickens, whereas no significant differences were found for WHC and purge loss between the breast and the leg, and between the two production systems as well. Results of sensory evaluation showed a significant preference for leg over breast meat (p<0.05). The scores of all the attributes including aroma, flavor, firmness, tenderness, juiciness and overall acceptability of leg meat from free-range chickens were slightly higher than for conventional chickens, while the reverse was true for breast meat, though no significant difference could be found. Free-range Taiwan native chicken appeared to yield the best of the results, with flavorful yet tender leg meat for higher sensory satisfaction, and high-protein but low-fat breast meat for healthier diet choice.

• Food Science of Animal Resources
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• v.22 no.2
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• pp.115-121
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• 2002

This study was carried out to investigate the effect of ultrasonic treatmeat time on the quality and palatability of fried chicken meat. Moisture content, U-10 treatment (chicken meat treated by ultrasonification for 10 minutes) of breast and leg were lower than those of the control, protein contents were not different between samples. Fat content was higher with increasing ultrasonic treated time. Frying loss of ultrasonic treated breast and leg were lower than those of the control, water holding capacity of ultrasonic treated breast and leg were higher than those of the control with increasing ultrasonic treated time. Rheological textures between control and ultrasonic treated samples were not different. L* value(lightness) between control and ultrasonic treated samples were not different, but L* values of breast were higher than those of the leg. And a* value(redness) was not effect by ultrasonic treatment, but a* value of leg were higher than those of the breast. Amino acid composition has included many glutamic acid, aspartic acid, lysine, leucine and arginine. Oleic acid and linoleic acid occupied beyond 50% of fatty acid composition. And taste, texture, juiciness and palatability improved with increasing ultrasonic treated time.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.10
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• pp.1380-1387
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• 2015

This study aims to determine the polymorphism and mRNA expression pattern of the heart-type fatty acid-binding protein (H-FABP) gene and their association with intramuscular fat (IMF) content in the breast and leg muscles of Baicheng oil chicken (BOC). A total of 720 chickens, including 240 black Baicheng oil chicken (BBOC), 240 silky Baicheng oil chicken (SBOC), and 240 white Baicheng oil chicken (WBOC) were raised. Three genotypes of H-FABP gene second extron following AA, AB, and BB were detected by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) strategy. The G939A site created AA genotype and G956A site created BB genotype. The content of IMF in AA genotype in breast muscle of BBOC was significantly higher than that of AB (p = 0.0176) and the genotype in leg muscle of WBOC was significantly higher than that of AB (p = 0.0145). The G939A site could be taken as genetic marker for higher IMF content selecting for breast muscle of BBOC and leg muscle of WBOC. The relative mRNA expression of H-FABP was measured by real-time PCR at 30, 60, 90, and 120 d. The IMF content significantly increased with age in both muscles. The mRNA expression level of H-FABP significantly decreased with age in both muscles of the three types of chickens. Moreover, a significant negative correlation between H-FABP abundance and IMF content in the leg muscles of WBOC (p = 0.035) was observed. The mRNA expression of H-FABP negatively correlated with the IMF content in both breast and leg muscles of BOC sat slaughter time.

• Korean Journal of Poultry Science
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• v.21 no.4
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• pp.277-284
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• 1994

The functional properties of mechanically deboned chicken meat(MDCM) from whole carcass, whole carcass without exsanguination, neck without skin, leg hone, and upper back and rib were studied. Also, the effects of adding different levels of gelatin and MDCM to the comminuted meats were investigated. Proximate composition values of MDCM ranged from 54.2 to 68.6% moisture, 14.5 to 19.7% protein, 12.3 to 30.1% fat, and 1.1 to 1.3% ash. The MDCM from leg hone had a higher content of fat, and a lower contents of moisture and protein. The MDCM from neck without skin tended to be opposite to the MDCM from leg hone. The total pigment and myoglobin levels were highest in MDCM from whole carcass without exsanguination such as 3.83 and 0.29 rng /g, and those from the other parts were 1.58~2.93 mg /g and 0. 17~0.31 mg /g, respectively. The emulsifying capacity and water holding capacity were highest in MDCM from neck without skin which contained lower levels of fat, collagen and hydroxyproline, but a higher level of salt soluble protein. The emulsifying capacity of comminuted meat decreased as gelatin content increased. The extractability of hydroxyproline from gelatin showed a higher solubility in acidic solution. The MDCM could he added up to 20% level without detrimentally affecting functional properties of comminuted meats although they had less water holding capacity and cooking loss as the proportion of MDCM increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1676-1684
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• 2004

Gel properties of recovered protein from mackerel, frozen blackspotted croaker, chicken breast and pork leg using acidic and alkaline processing were evaluated. Myofibrillar protein from mackerel by acidic processing did not form a heat-induced gel. However, the recovered protein including sarcoplasmic protein formed heatinduced gel. Breaking force of gel from mackerel processed at pH 10.5 was the lowest. A deformation value of frozen blackspotted croaker was the highest, followed by chicken breast, pork leg and mackerel. Whiteness of frozen blackspotted croaker was the highest among heat-induced gel. Breaking force, deformation and whiteness were decreased by addition of recovered protein from mackerel, but price was increased. A breaking force and whiteness of heat-induced gel added recovered protein from chicken breast were increased, and the price was greatly decreased. When the constraint of breaking force, deformation and price of raw material were set up above 110 g, 4.5 mm and below 2,000 won/kg. A optimum formulation for blending protein was 36∼50% for frozen blackspotted croaker, 34∼40% for chicken breast, 14∼25% for pork leg. The heat-induced gel of recovered protein from frozen blackspotted croaker showed compact structure compared to that of recovered protein from mackerel. A formulation of chicken breast and pork leg based on blackspotted croaker can be used in surimi based seafood products having various texture.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.5
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• pp.732-737
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• 2008

This study developed a natural ingredient as a functional food possessing properties of attenuation of hypertension and cardiovascular hypertrophy. In a previous study hydrolysates obtained from chicken leg bone protein using Alcalase strongly inhibited angiotensin I converting enzyme (ACE) in vitro. In particular, hydrolysate (A4H) from four hours of incubation exhibited the highest ACE inhibitory activity (IC50 = 0.545 mg/ml). A4H was selected as a potent ACE inhibitor and orally administrated to spontaneously hypertensive rats (SHR) for eight weeks to investigate attenuating effects on age-related development of hypertension and cardiovascular hypertrophy. Results showed that treatment with A4H of SHRs attenuated the development of hypertension as effectively as the clinical antihypertensive drug captopril. Moreover, a significantly lower heart to body weight ratio and thinness of coronary arterial wall was observed in SHRs that had been treated with A4H or captopril. The results suggest that A4H can be utilized in developing an ACE inhibitor as a potential ingredient of functional foods to alleviate hypertension and cardiovascular hypertrophy.

• Nutrition Research and Practice
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• v.13 no.6
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• pp.480-487
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• 2019

BACKGROUND/OBJECTIVES: Osteoarthritis (OA) is a major public health issue in Japan and other countries, and foods that prevent or treat OA are in strong demand. Proteins and peptides in chicken meat and bones are known for being rich in functional and nutritional ingredients for the improvement of osteoporosis. We speculated that chicken legs, a food consumed in many regions of the world, may also contain such ingredients. In this study, we aim to (i) evaluate the effect of chicken leg extract (CLE) on the promotion of cartilage matrix production and (ii) identify the active ingredient in CLE that contributes to this function. MATERIALS/METHODS: Artificial CLE digest was prepared, and the acid mucopolysaccharide production-promoting activity of the CLE digest was evaluated by alcian blue staining of ATDC5 cells. CLE was orally administered to rabbits with burr holes in the knee joint of the femur, and the degree of regeneration of cartilage matrix was evaluated. Furthermore, we investigated orally administered CLE-derived peptides in human plasma using LC-MS. From measuring the acid mucopolysaccharide production-promotion activity of these peptides, a molecule considered to be an active ingredient in the CLE digest was identified. RESULTS: CLE digest promoted acid mucopolysaccharide production and facilitated regeneration of cartilage matrix in in vitro and in vivo experiments. Four peptides including phenylalanyl-hydroxyproline (Phe-Hyp) were detected as CLE-derived peptides in human plasma. The effect of CLE was inferred to be due to Phe-Hyp, which was confirmed to be present in the CLE digest. CONCLUSIONS: It was shown that CLE stimulated the production of articular cartilage matrix both in vitro and in vivo, and that CLE could be an effective food for preventing or treating OA. Furthermore, only Phe-Hyp was confirmed as the active compound in the CLE digest, suggesting that the activity of CLE was due to Phe-Hyp.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2002.11a
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• pp.126-126
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• 2002

• Korean Journal of Agricultural Science
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• v.39 no.2
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• pp.195-202
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• 2012

This study was examined the optimization of processing conditions for taste-assurance factors of boiled Korean native chicken (KNC) through response surface methodology. The effects of two independent variables, including heating time ($X_1$) and water volume ($X_2$), were investigated using central composite design. Hypoxanthine content, lipid oxidation, texture, and sensory results were chosen as dependent variable. Results showed high reliability on hypoxanthine and texture property in leg meat (not breast meat) of boiled KNC. Statistical modeling revealed that 3.5 folds of added water (v/w) based on chicken weight and 73.5 min of cooking time was the optimum for producing characteristic taste and textural properties from the leg meat of KNC.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.269-278
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• 2007

This study was performed to measure the pH, proximate composition, physicochemical properties, changes of protein bands, Hunter color values and endpoint cooking temperature of chicken leg and breast muscles during cooking from 64 to 74℃ with 2℃ increments. Chicken leg had higher pH, moisture and fat contents (%) and lower protein solubility(P<0.05) than chicken breast. Although the cooking losses(CLs, %) of chicken muscles increased with increased cooking temperature, the addition of 2% salt did not affect CL. The redness values of chicken leg without 2% salt were higher than chicken breast, however, the addition of 2% salt reduced the differences of the redness. Protein solubility decreased with increased cooking temperatures and were not affected by the addition of salt, and no further changes were observed higher than 68℃. Protein bands having the molecular weights of 66 and 54kDa were disappeared in the chicken leg at the cooking temperatures of 66～70℃, whereas 66, 54 and 34kDa in the chicken breast. These protein bands could be used potential indicators to determine the endpoint cooking temperature in chicken muscles.