• Culinary science and hospitality research
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• v.16 no.5
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• pp.287-298
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• 2010

This study aims to develop chicken stock, which is the base of sauce, soup, etc., using various nourishing elements in chicken bones. For this purpose, we prepared chicken stock with varying the amounts of tomato added in order to produce basic data for enhancing the taste and nutrition of chicken stock, improving the quality of stock-based dishes, and developing stock. Sensory characteristics of tomato chicken stock such as water, ash, color, sugar, pH and sensory tests were studied by adding tomatoes for finding out the effect on free amino acid and various nutrients. The total free amino acid content and general acceptance were highest when 7.4% of tomato added. Based on the results of this study, the optimal tomato content for maximizing the overall quality of chicken stock was 7.4%.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.1003-1014
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• 2022

This study investigated quality characteristics of chicken stock with added plum extract (PE) and green tea powder (GP) stock during storage. Plum extract (0, 0.5, 1, 3%) and green tea powder (0, 0.5, 1, 3%) were added at three levels. Chicken stock was stored at room temperature for 14 days. The pH of the chicken stock decreased significantly as the content of PE and GP increased (p < 0.05). The group with 3% plum extract added showed significantly lower pH values (p < 0.05). Total numbers of microorganisms (TMC) showed significant differences according to the storage period (p < 0.05), where the groups with PE and GP added showed lower TMC values than the control group, This indicates that PE and GP could inhibit the growth of microorganisms. The addition of 3% PE or GP decreased lipid oxidation (TBARS) and protein deterioration (VBN) values. In sensory test, the results showed that adding PE or GP has a positive effect on storage characteristics of chicken stock. The addition of PE rather than GP is effective not only in improving sensory evaluation, but also in minimizing changes in quality by suppressing lipid oxidation and protein deterioration during storage. In conclusion, 3% PE addition was found to be the most optimal supplementation choice for increasing the storability of chicken stock.

• Culinary science and hospitality research
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• v.14 no.4
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• pp.283-291
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• 2008

The present study is purposed to suggest accurate guidelines for developing standardized chicken meat stock containing salt, and to develop a product for mass production of uniform quality achieved by applying High Pressure Extraction Cooking(HPEC) using a high.pressure extractor. Through this study, we examined water contents, ash contents, salinity, turbidity and mineral contents of chicken meat stock according to the addition of salt. The ash contents increased with the increase of the addition of salt, but the water contents decreased with the increase of the addition of salt. Salinity increased with the increase of the addition of salt. Turbidity decreased with the increase of the addition of salt, and difference in turbidity according to the addition of salt was regular. Among mineral contents, Na showed the highest content, which was believed to be because of the addition of salt, and it was followed by K and P. The results of this study show that the mineral contents in the stock were different according to the addition of salt, but they were neither proportional to the addition of salt nor showed a regular pattern.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1028-1033
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• 2004

This study was conducted to improve the quality properties of cream soup in accordance with the added amount of sweet pumpkin and Chungdong pumpkin, roux and chicken stock. As the amount of pumpkin was increased, red (a-value) and yellow (b-value) colors increased but its lightness (L-value) remarkably decreased. Also, there was a significant differences in viscosity, color, appearance and overall preference of sensory evaluation. In pumpkin 150 g (37.5%) added, the degree of total preference was high. As the added amount of roux was increased, red and yellow colors decreased by small margin and there was a significant differences in color, flavor, appearance and overall preference of sensory test. At adding roux of 5 mL (1.5%) showed the highest preference. With the adding chicken stock increase the lightness, red and yellow color decreased. It was found by sensory evaluation that there were significant differences in viscosity, color, flavor, appearance and overall preference. At adding chicken stock 150 mL (37.5%) and milk of 50 mL (12.5%) showed the high score in flavor, appearance and total preference.

• Korean Journal of Poultry Science
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• v.47 no.1
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• pp.1-7
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• 2020

The effect of stocking density on the growth and meat quality of native Korean chickens was investigated. A total of 364 one-day-old native Korean chickens were randomly assigned to one of 5 treatments, each of which was replicated 4 times. Five distinct stocking densities-14, 15, 16, 18, and 22 birds/㎡-were compared. The diet was fed ad libitum for 10 weeks. Results indicated that the final body weight, body weight gain, and feed intake were lower (P<0.05) for the 22 birds/㎡ stock density as compared to the other stock densities. There was no significant difference in the feed conversion ratio, proximate analysis (DM, crude protein, crude fat, and crude ash), water-holding capacity, and cooking loss among the different stock densities. These results indicate that increasing the stock density to 22 birds/㎡ elicits some negative effects on the growth performance and meat quality of Korean-native chickens.

• Korean Journal of Poultry Science
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• v.48 no.2
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• pp.91-100
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• 2021

The study determined the effects of stock density (SD) and energy level (EL) on growth performance, serum biochemistry, and meat quality in Korean native chickens. A total of 240 chickens were randomly assigned to one of the four treatments including two stock density (low, 14, and high, 16 chickens per m²) and two energy level (low, 2,950, 3,000, 3050 ME kcal/kg, and high 3,150, 3,200, 3,250 ME kcal/kg, for starter, grower, and finisher, respectively). During the whole period of the experiment, the chickens were fed ad libitum. The greater final body weight and weight gain were achieved in chickens fed high energy diet, whereas the final body weight and weight gain were significantly reduced in high-density treatment compared with the low density. Chickens in low-density groups had a higher feed intake compared with high-density treatment, however, the energy level did not affect the feed intake. An improved overall feed conversion ratio was detected in the high energy treatment. There was a significant interaction between stock density and energy level on cholesterol concentration. The concentration of aspartate transaminase in serum was increased by higher stock density. There was a significant treatment interaction on IgM levels. Moreover, the carcass rate was significantly increased in the high energy level treatment. Based on the findings, we suggest that rearing chickens in low density with high dietary energy levels could be beneficial by improving the growth performance.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.219-228
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• 2016

A total of 720 slow-growing Korean meat-type (Hanhyop 3) chicken were used to evaluate the effect of stocking densities and dietary protein levels on growth performance, meat quality, bone mineral composition, and serum corticosterone. Three (6.3, 9.5, and $12.6birds/m^2$) stocking densities and two dietary protein levels (19% and 18%) were factorially ($3{\times}2$) arranged for six treatments. Overall body weight gain (BWG) was highest (p<0.001) at the lowest stocking density ($6.3birds/m^2$). The feed intake (FI) of birds at the highest density ($12.6birds/m^2$) was lower than that of birds at the other densities, but resulted in better feed/gain (F/G). Among 18% protein groups, the overall FI of birds at $9.5birds/m^2$ was higher than that at the lowest density; therefore, birds at $9.5birds/m^2$ had poorer F/G than birds at the lowest density during days 61~75. Difference in F/G among densities was only significant (p<0.05) during days 61~75 but not significant (p>0.05) during days 41~60. Although there were no significant differences (p>0.05) in BWG and F/G between 19% and 18% dietary protein levels, FI of the 18% protein diet was less (p<0.05) than that of the 19% diet. Although there was no difference (p>0.05) in meat TBARS values, meat color differed (p<0.05) with stocking density and dietary protein levels. There was no effect (p>0.05) of stocking density and dietary protein levels on bone mineral composition. Serum corticosterone concentration increased (p<0.05) with increasing stock density but was not affected (p>0.05) by dietary protein levels. This study indicated that a density of $12.6birds/m^2$ is not recommended for slow-growing chickens. Between 19% and 18% dietary protein levels, 18% would be recommended for the Korean Hanhyop 3 chicken in the finishing stage.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.83-95
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• 2024

This study aimed to assess the performance of laying hens across twelve crossbreed strains (i.e., CFCK, CFYC, CFYD, CKCF, CKYC, CKYD, YCYD, YCCF, YCCK, YDCF, YDCK, and YDYC) of Korean native chicken (KNC) and compare them with Hy-Line Brown layers. A total of 287 18-week-old laying hens were placed in battery cages by strains (2-5 birds per pen). Results indicated that the YCYD and YDYC strains exhibited numerically heavier body weights than Hy-Line Brown at week 18-64. CKYC and YDYC strains demonstrated more than 94% viability by week 64. The CFYC strain had an age of first egg laying of 127 days, and the YDCF strain reached an age of 50% egg production at 140 days, both earlier than their parent stock. The YDCF strain showed over 70% egg production for up to 60 weeks. Regarding egg quality, the CKCF and YCCF strains had numerically higher egg weights among the KNC groups at week 24-64, with the YDYC strain showing a darker (P<0.05) eggshell color compared to CKCF at week 40. Moreover, KNC crossbreeds showed a higher (P<0.05) egg yolk ratio than Hy-Line Brown. In conclusion, the YDCF and YCCF crossbreeds exhibited the most desirable new synthetic Korean native commercial layer based on egg production and quality parameters. Therefore, these strains could be a viable substitute for Hy-Line Brown layers.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.203-212
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• 2023

This study conducted a diallel-crossbreeding test using four Korean native chicken parent stock lines (YC, YD, CK, and CF) to develop a native commercial layer with high egg-laying performance. A total of 312 chickens in six combinations were examined for various traits, including livability, body weight, age at first egg-laying, hen-day, and hen-housed egg production, egg weight, and egg quality, from hatching to 60 weeks of age. The results showed that the average survival rate was 77.1±18.8% with the YDYC combination having the highest survival rate along with excellent specific combining ability. The YDYC combination exhibited significantly higher body weight compared to the other combinations (P<0.01). The average age at first egg-laying was 121.3±2.5 days, with no significant difference between the combinations. The average hen-day egg production was 74.0±6.4%, and the hen-housed egg production was 181.4±33.8 eggs with the YDCF and YCCK combinations demonstrating the highest laying performance, while the YDYC and CKCF combinations had the lowest (P<0.05). Laying performance was more influenced by specific combining ability than general combining ability. The eggs from the YDYC combination were significantly lighter and had the darkest shell color (P<0.01), whereas the YDCF combination exhibited the thickest eggshells. There was no difference in internal egg quality among combinations, except the YDCF combination had the darkest yolk color. Overall, we concluded that the YCCK combination, characterized by high laying performance and livability, and the YDCF combination with high laying performance and good egg quality are the most desirable combinations for Korean native commercial layers.

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.239-253
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• 2021

This study investigates the metabolomic changes in breast and thigh meat from Cobb and Ross 308 chickens regarding the rearing environment. One-day-old Cobb and Ross broilers were raised for 35 days in conventional and animal welfare farms with, amongst others, different floor sizes, stock densities, and ammonia concentrations. One-dimensional ¹H nuclear magnetic resonance, orthogonal partial least squares-discriminant analysis (OPLS-DA), and pathway analyses were performed to analyze the metabolomic properties of broiler meat. For breast meat, only those from the Ross strain could be separated according to the environment in the OPLS-DA plot. Ross breast meat from animal welfare farms showed significantly higher acetate, anserine, creatine, and inosine monophosphate content than those from conventional farms (P<0.05). In contrast, for thigh meat, the Cobb strain was differentiated using OPLS-DA. The contents of five metabolites, such as glucose and lactate, were higher in thigh meat from animal welfare farms; however, nine metabolites, including seven free amino acids, were lower compared to those from conventional farms (P<0.05). Pathway analysis was performed to interpret the biological changes in chicken meat based on environmental factors. The results indicated that the animal welfare environment led to significant changes in four metabolic pathways in Ross breast meat and in 20 metabolic pathways in Cobb thigh meat (P<0.05). In conclusion, the animal welfare environment could influence the metabolomic properties of Ross breast meat and Cobb thigh meat, which may affect the sensory quality of meat.