Hyun-Seok Chae

Effect of Dietary Supplementation of Quercetin on Oxidative Stability of Chicken Thigh

This study was carried out to determine the effect of dietary supplementation of quercetin and methoxylated quercetin extracted from onions on oxidation of chicken thigh during cold storage. For 35 days, 1-day-old 320 broiler chicks (Ross) were divided into 8 groups and supplemented the diet; basal diet only (T1), T1 with antibiotics (T2), vitamin E 20 IU (T3), vitamin E 200 IU (T4), quercetin 20 ppm (T5), quercetin 200 ppm (T6), methoxylated quercetin 20 ppm (T7), methoxylated quercetin 200 ppm (T8). After slaughtering the broilers, thigh meats were collected and analyzed the oxidation stability during storage at 4 for 7 days. Volatile basic nitrogen (VBN) was ranged from 10.98 15.37 mg% until day 3 and quercetin 20 ppm (T5) significantly reduced (p<0.05) the VBN value of thigh as much as antibiotics treatment group (T2). The supplementation of quercetin at a 200 ppm level significantly reduced 2-thiobarbituric acid reactive substances value when compared with the control. Supplementation of 20 ppm quercetin also affected fatty acid composition of chicken thigh and resulted in increase of C18:1w9 and decrease of C18:2w6 on day 3. In microbes of chicken thigh during storage, supplementation of 20 ppm quercetin significantly reduced total microbes compare to control on day 7 (p<0.05). There was no effect on the number of coliforms in thigh with quercetin diet. From these results, the dietary supple- mentation of 20 ppm of quercetin may have effects on enhancing oxidation stability.

A research note on predicting the carcass yield of Korean native cattle (Hanwoo).

This study developed a new equation to predict the carcass yield of Hanwoo cattle, as well as re-evaluating a previous prediction equation. Experimental animals comprised 79 cows, 79 steers, and 79 bulls. A stepwise model selection was performed to determine the most practical carcass traits for predicting the yield. Cold carcass weight (CW), backfat thickness (BFT), and ribeye area (REA) accounted for 52% variation in yield, and these were determined as the final parameters. When the kidney, pelvic, and heart fat were included in the model, this increased the percentage variation explained (R(2)) by 4%. To compare the newly developed equation (Yield=64.65-0.0198×CW-5.2264×BFT+0.1339×REA) and the previously used one, carcass yields of 377,048 industrial animals (145,695 cows, 225,926 bulls, and 5427 steers) were assessed. For the newly developed equation, the mean difference between experimental animals industrial animals differed only by 1.99-2.68% for all sex groups. In the case of the previous prediction equation, the mean difference ranged from 6.06% for bulls to 11.05% for steers. The results demonstrated that the prediction equation should use a mixture of sex and market weight groups. The results also support our decision to use the newly developed model in predicting the yield of Hanwoo.

Effects of Raising Periods on Physico-Chemical Meat Properties of Chicken

National Institute of Animal Science, RDA, Suwon 441-706, KoreaABSTRACT This study was conducted to investigate the effect of different raising days (30, 36, 42) on physico-chemical meat quality properties of chicken breasts and legs stard with 1 day old. In chemical compositions, moisture and protein contents (%) were decreased whereas fat contents (%) were increased as the raising days. In mineral contents, there was not significantly different in calcium contents. However, there was a decrease of potassium contents (p<0.05) as raising periods increased. Nucleotide-related compounds were 121.0 mg/100 g at 30 day, 130.4 at 36 day and 131.2 at 42 day, respectively. However, they were not significantly different during the raising periods (p<0.05). The similar tendency was observed in leg parts. L* values were decreased especially for chicken raised for 42 days. b* values were gradually increased as the raising periods increased. Cooking loss (%) was decreased whereas Warner-Bratzler shear forces (WBS) were increased as the raising periods increased.(Key words : raising days, mineral, meat color, physical property)

Chemical Composition and Meat Quality of Crossbred Korean Native Chickens (KNC)

This work was carried out to investigate chemical composition and meat quality of crossbred Korean native chickens (KNC). Ninety 1-d male chicks were used in this work and were divided into 4 groups as A: (KNC egg-meat type C strains × KNC meat type S strains) ( ) × KNC meat type H strains ( ), B: (KNC egg-meat type C strains × KNC meat type H strains) ( ) × KNC meat type S strains ( ), C: (KNC native R strains × KNC meat type S strains) ( ) × KNC meat type H strains ( ), D: (KNC native L strains × KNC meat type H strains) ( ) × Ross broiler ( ) strains. They were fed the broiler diets for 12 weeks at the flat house and twenty seven chickens were slaughtered at week 5 and 10. Chicken thigh and breast were weighed and physicochemical compositions and sensory characteristics were investigated. Physical compositions of meats have no difference among strains at 5 week, and B strains differed from other strains at 10 week (P<0.05). The pH, moisture, and collagen content of meat from B strains were lower than other strains at 5 week. Ash and collagen of A strains were the lowest at 10 week (P<0.05), but others have no difference among strains. In sensory test, juiciness of D strains was the highest at 5 week, and tenderness of B strains was the lowest at 10 week (P<0.05). In conclusion, the crossbreeding of KNC did not affect physical traits but affected chemical composition of the chicken meat slaughtered at 5 week.

A Comparative Study on Performances and Carcass Traits in Three Major Meat-Type Duck Strains in Korea

The present experiment was carried out to compare performance, carcass characteristics and meat quality among three major meat-type duck strains in Korea. Two commercial duck (CD) strains, produced from parent stocks (PS) (Cherry Valley and Grimaud), and F1 strains, self-produced by farmers, were used in an 8-week feeding experiment. Both feed conversion ratio and production index were significantly higher in Cherry Valley strain compared with the other two at the ends of 6 and 8 weeks (p<0.05). However, no differences were found in carcass characteristics and meat quality, with the exception of abdominal fat weight where Grimaud were higher than the others. Overall, the results of the current study show that Cherry Valley CD strain 10

Anti-oxidative Activity and the Protective Effect of Donkey`s Bone and Skin Extracts on SK-N-SH Cells

The aims of this study were to determine antioxidation effect and neuroblastoma cell protection effect of donkey`s bone and skin extracts (DBSE). DBSE was extracted by a pressure-cooker for 48 h and lyophilized. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was significantly increased with increased doses of DBSE and 40 mg/ml of DBSE showed 95.43% of the DPPH scavenging effect, which was equivalent to 1 mg/ml of vitamin C. The 2,2`-azino-bis (3-ethylbenzothiazoline-6- sulphonic acid) (ABTS) radical scavenging activity was also increased in a dose-dependent manner, and 20 mg/ml of DBSE showed 88.73% of the ABTS scavenging effect. The oxygen radical absorbance capacity ( Trolox equivalent) of DBSE was significantly increased at a concentration of 10 mg/ml, which showed TE. The viability of oxidatively stressed brain cells induced by was protected by DBSE at concentrations greater than . Cell viability after DBSE treatment at 50 and was 53.78 and TE, respectively. There was no significant difference between both doses; however, 200 and of DBSE showed 59.74 and 66.08% of cell viability, respectively indicating that DBSE protected SK-N-SH from oxidation stress. These results suggest that DBSE may have potential to be used as natural antioxidants in food industry, while in vivo evidence is necessary to support DBSE`s in vitro-based antioxidative efficiency.

Effect of heating system using a geothermal heat pump on the production performance and housing environment of broiler chickens.

A geothermal heat pump (GHP) is a potential heat source for the economic heating of broiler houses with optimum production performance. An investigation was conducted to evaluate the effect of a heating system using a GHP on production performance and housing environment of broiler chickens. A comparative analysis was also performed between the GHP system and a conventional heating system that used diesel for fuel. In total, 34,000 one-day-old straight run broiler chicks were assigned to 2 broiler houses with 5 replicates in each (3,400 birds/replicate pen) for 35 d. Oxygen(,) CO(2), and NH(3) concentrations in the broiler house, energy consumption and cost of heating, and production performance of broilers were evaluated. Results showed that the final BW gain significantly (P < 0.05) increased when chicks were reared in the GHP broiler house compared with that of chicks reared in the conventional broiler house (1.73 vs. 1.62 kg/bird). The heating system did not affect the mortality of chicks during the first 4 wk of the experimental period, but the mortality markedly increased in the conventional broiler house during the last wk of the experiment. Oxygen content in the broiler house during the experimental period was not affected by the heating system, but the CO(2) and NH(3) contents significantly increased (P < 0.05) in the conventional broiler house compared with those in the GHP house. Fuel consumption was significantly reduced (P < 0.05) and electricity consumption significantly increased (P < 0.05) in the GHP house compared with the consumption in the conventional house during the experiment. The total energy cost of heating the GHP house was significantly lower (P < 0.05) compared with that of the conventional house. It is concluded that a GHP system could increase the production performance of broiler chicks due to increased inside air quality of the broiler house. The GHP system had lower CO(2) and NH(3) emissions with lower energy cost than the conventional heating system for broiler chickens.

Comparison of Pork Quality by Different Postmortem pH24 Values

Meat quality of the domestic pork loins(n=537) classified by 3 groups(5.31-5.50, 5.51-5.70 and 5.71) according to pH at 24hr post-mortem(pH24) was investigated. In proximate chemical compositions, protein was highest and fat was lowest in the pork loins of pH24 5.31-5.50 group. Water holding capacity increased as pH24 increased, whereas purge loss and cooking loss decreased as pH24 increased. Meat color values(CIE L*, a*, b*, Chroma, Hue and E) decreased as increased. In texture traits, hardness and chewiness were lowest and fat hardness was highest in the pork loins of 5.71 group when compared to the other groups. However, Warner-Bratzler Shear force, springiness and cohesiveness were not significantly different among the pH24 groups(P>0.05). In sensory properties, juiciness and tenderness were highest in 5.71 group. From the results of this study, pork quality was highly related to . Therefore, the factors affecting the post-mortem pH, such as stress before slaughter, slaughtering methods, and cooling condition slaughter must be properly controlled and improved to produce high quality pork.

Analysis of Carcass Quality Grade Components and ChemicoPhysical and Sensory Traits of M. longissimus dorsi in Hanwoo

The current study was conducted to analysis the effects of sex and live weight on carcass characteristics us- ing total 773 Hanwoo, and to assess the effects of quality grade on chemico-physical and sensory character- istics in longissimus muscle. Results show that both steer and cow received superior quality grade to bull within the same weight class(P < 0.05). Marbling score, texture, maturity, meat color and fat color were sig- nificantly(P < 0.01) affected by sex, whilst only marbling score and maturity were significantly affected by live weight. The ultimate quality grade showed significant relationships with marbling score(r = 0.81 ** ), meat color (r = 0.21 ** ), fat color(r = 0.10 ** ), and with texture(r = 0.41 ** ), but that had no such a relationship with maturity. WB-shear force and cooking loss were decreased when carcass grade was increased(P < 0.01), but water-holding capacity was identical between the quality grades. Objective meat color dimensions in lightness, redness and yellowness were increased for higher quality grade(P < 0.01). Meat flavor, juiciness and tenderness received higher scores for higher quality grade(P < 0.01). Intramuscular fat content had significantly relationships with WB-shear force(r = 0.56 * ), water-holding capacity(r = 0.18 ** ), juiciness(r = 0.46 ** ), tenderness(r = 0.49 ** ), and flavor

Effect of Crossbred Korean Native Ducks on the Retail Cut Yield, Meat Quality, and Sensory Evaluation of Duck Meats

This work was carried out to investigate on the retail cut yield and the meat quality of crossbred ducks. A total of 360 pullets that were produced from 4 mating methods used in this work. Four mating method were A) native ducks ( ) × native ducks ( ), B) meat-type ducks ( ) × native ducks ( ), C) native ducks ( ) × meat-type ducks ( ), and D) meat-type ducks ( ) × meat-type ducks ( ). Ducks were bred at the flat house, and selected nine ducks with similar weights from each treatment at the certain weeks (A, B, C 8 weeks; D 6 weeks). Selected ducks were slaughtered, calculated the retail cut yield(wing, back, neck, breast, leg), analyzed the physico-chemical compositions, and tested the sensory evaluation. Wing and neck meat ratios of D treatment were lowest (P<0.05), and breast meat ratio of B treatment was high (P<0.05) compared to other treatments. pH of duck meat was no difference among treatments, fat and protein contents of B treatment was highest, and collagen contents of D treatment was highest among all treatments. Meat color and physical compositions was no difference among treatments. Juiciness of D treatment meats was highest, and there was no difference between B and D treatments. Finally, mating method of native duck and meat-type duck affected on the retail cut yield,