Quality comparison of retorted Samgyetang made from white semi-broilers, commercial broilers, Korean native chickens, and old laying hens.

OBJECTIVE: The aim of this study was to compare the quality characteristics of retorted Samgyetang (Korean ginseng chicken soup) made from white semi-broilers (WSB; Ross× Hyline white, 3 weeks old), commercial broilers (CB; Ross, 4 weeks old), Korean native chickens (KNC; Hanhyup-3-ho, 12 weeks old) and old laying hens (OLH; Hyline white, 72 weeks old) and to explore the possibility of using the carcasses of KNCs and OLHs as raw material for product diversification. METHODS: Raw and cooked meat quality, fatty acid composition and consumer acceptance were analyzed. RESULTS: Among the chicken breeds, OLH and KNC showed a higher shear force value than WSB and CB due to high insoluble collagen contents. However, the meat of KNC was more tender than that of OLH. The meat of OLH was characterized by the lowest moisture content and highest crude fat content. The meat of KNC was characterized by a higher proportion of saturated fatty acids, α-linolenic acid and arachidonic acid than that of OLH. The meat of OLH showed the highest content of unsaturated fatty acid, particularly linoleic acid, in its thigh meat. Electronic nose readings revealed that the meat aroma pattern was clearly different across breeds. OLH had the lowest overall acceptance score, while no differences were found in flavor, texture, juiciness and appearance among WSB, CB, and KNC. CONCLUSION: KNC shows potential as raw material for Samgyetang, while additional preprocessing methods, such as tenderization and fat removal, are required for the utilization of OLH as raw material for retorted Samgyetang.

The effect of finishing diet supplemented with methionine/lysine and methionine/α-tocopherol on performance, carcass traits and meat quality of Hanwoo steers.

OBJECTIVE: This study aimed to compare the effects of diets with and without supplements of methionine/lysine (met/lys) and methionine/α-tocopherol (met/α-tocopherol) on the performance, carcass traits and meat quality of Hanwoo steers. METHODS: A total of 21 Hanwoo steers were divided into three different groups. Each group consisted of 7 animals that received different dietary treatments for 120 days as follows: a control (C) diet composed of a basal diet with 74% total digestible nutrient and 12% crude protein; treatment 1 (T1) composed of a basal diet enriched with methionine 69%+lysine 31%; and treatment (T2) composed of a basal diet enriched with methionine 84.65%+α-tocopherol 15.35%. Daily supplementation was given using the top-dressing method (20 g/animal). RESULTS: The met/lys groups yielded a longissimus lumborum with increased water holding capacity (p<0.01) and lower shear force value (p<0.05). Dietary met/lys did not have an adverse effect on the animal performance and carcass traits. Instead, these supplements contributed significantly to the higher protein content compared to the control diet (p<0.05). Myristic acid (C14:0) was the only fatty acid affected by the supplementation. While the met/α-tocopherol group led to significantly higher protein and oxymyoglobin contents during storage (p<0.05). It also contributed significantly to the lower shear force value and 2-thiobarbituric acid reactive substances score during storage (p<0.05) compared to the control and treatment 1 since the initial storage day. The met/α-tocopherol diet also yielded meat with a redder color (p<0.05) after 3 days of storage. However, it did not significantly contribute to the fatty acid profiles of Hanwoo steers. CONCLUSION: Met/lys supplementation resulted in higher protein scores, water holding capacity and lower shear force scores. While met/α-tocopherol supplementation contributes to the production of redder meat, reduces lipid oxidation, production of more tender meat and increases the content of protein and oxymyoglobin percentage.

Comparison of meat quality, fatty acid composition and aroma volatiles of dry-aged beef from Hanwoo cows slaughtered at 60 or 80 months old.

OBJECTIVE: The objective of this study was to compare the quality of dry-aged beef from cull Hanwoo cows slaughtered at 60 or 80 months old. METHODS: A total of eight cull Hanwoo carcasses with a quality grade of 3 (low-grade) were selected and divided into two age groups: 63.5±2.5 months old (n = 4) and 87.8±4.5 months old (n = 4). Whole longissimus thoracis et lumborum from the 11th rib to the last lumbar vertebrae, including the back fat, was removed from the carcass at 24 h postmortem and aged for 50 days in darkness at a temperature of 2°C±1°C, a relative humidity of 85% and an air flow of 2 m/s. The sampling was performed aseptically after 0, 20, 24, 40, and 50 days of aging. RESULTS: Regardless of the aging period, aging increased the lightness (p<0.05), redness (p<0.05) and yellowness (p<0.05) at initial blooming (90 min after slicing) and the overall acceptance (p<0.05). No further tenderization effect was found after 20 days of aging, but aging for 50 days significantly increased the lipid oxidation (p<0.05). The generation of aroma volatiles in the roast steak from aged samples was higher (p<0.05) than that of non-aged samples. No significant effect of age at slaughter was found on the color, pH, water-holding capacity, cooking loss, shear force value, bacterial counts, volatile basic nitrogen, consumer acceptance, lipid oxidation, fatty acid composition or aroma volatiles. CONCLUSION: The quality of dry-aged beef obtained from cull Hanwoo cows slaughtered at either 60 or 80 months old with similar quality grade was comparable and extending dry aging for more than 40 days is not recommended considering the costs and further lipid oxidation.

Comparison of meat quality, fatty acid composition and aroma volatiles of Chikso and Hanwoo beef.

OBJECTIVE: Although Hanwoo has been selected as the superior commercial beef cattle breed in Korea, Chikso (Korean brindle cattle) is still recognized as a valuable breed for beef production. The aim of this study was to compare the meat quality, fatty acid composition and aroma volatiles of beef from Chikso and Hanwoo steers maintained under identical feed management, as information regarding these characteristics is still limited. METHODS: A total of 19 carcasses with a quality grade of 1 were selected, and strip loin (longissimus lumborum) cuts were collected from 11 Hanwoo carcasses and 8 Chikso carcasses. Meat quality and aroma analyses were performed at day four postmortem. RESULTS: Though Hanwoo strip loin tended to have higher fat content (15.37%) than Chikso (12.01%), no significant differences were observed. Meat pH, water-holding capacity, cooking loss, shear force value, instrumental surface color (Commission International De L'eclairage L*, a*, b*, chroma, and hue angle) and fatty acid composition were not significantly different. Roasted Chikso beef released more intense aroma than roasted Hanwoo beef based on the total area units of identified volatiles. Among identified volatiles, the amounts of toluene, heptanal, octanal, and nonanal were higher in roasted Chikso beef than in roasted Hanwoo beef. In addition, the aroma pattern of the roasted beef from these breeds was well-discriminated by electronic nose. CONCLUSION: No distinct differences were found in terms of meat quality between Hanwoo and Chikso beef in this study. However, the aroma pattern and volatiles of roasted Hanwoo and Chikso beef were different according to instrumental analysis.

Effects of cooking method and final core-temperature on cooking loss, lipid oxidation, nucleotide-related compounds and aroma volatiles of Hanwoo brisket.

OBJECTIVE: This study observed the effects of cooking method and final core temperature on cooking loss, lipid oxidation, aroma volatiles, nucleotide-related compounds and aroma volatiles of Hanwoo brisket (deep pectoralis). METHODS: Deep pectoralis muscles (8.65% of crude fat) were obtained from three Hanwoo steer carcasses with 1+ quality grade. Samples were either oven-roasted at 180°C (dry heat) or cooked in boiling water (moist heat) to final core temperature of 70°C (medium) or 77°C (well-done). RESULTS: Boiling method reduced more fat but retained more moisture than did the oven roasting method (p<0.001), thus no significant differences were found on cooking loss. However, samples lost more weight as final core temperature increased (p<0.01). Further, total saturated fatty acid increased (p = 0.02) while total monounsaturated fatty acid decreased (p = 0.03) as final core temperature increased. Regardless the method used for cooking, malondialdehyde (p<0.01) and free iron contents (p<0.001) were observed higher in samples cooked to 77°C. Oven roasting retained more inosinic acid, inosine and hypoxanthine in samples than did the boiling method (p<0.001), of which the concentration decreased as final core temperature increased except for hypoxanthine. Samples cooked to 77°C using oven roasting method released more intense aroma than did the others and the aroma pattern was discriminated based on the intensity. Most of aldehydes and pyrazines were more abundant in oven-roasted samples than in boiled samples. Among identified volatiles, hexanal had the highest area unit in both boiled and oven-roasted samples, of which the abundance increased as the final core temperature increased. CONCLUSION: The boiling method extracted inosinic acid and rendered fat from beef brisket, whereas oven roasting intensified aroma derived from aldehydes and pyrazines and prevented the extreme loss of inosinic acid.

Effects of high-pressure processing on taste-related ATP breakdown compounds and aroma volatiles in grass-fed beef during vacuum aging.

OBJECTIVE: This study aimed to observe whether high-pressure processing (HPP) affected aroma development and the degradation rate of umami taste-related ATP breakdown products, specifically inosinic acid in grass-fed beef during vacuum aging. METHODS: Strip loin (longissimus lumborum) cuts obtained from six grass-fed Friesian Holstein steers (32 months old) on day 4 post slaughter were vacuum-packed and subjected to pressurization at 300 and 500 MPa for 180 s at 15°C±2°C. The samples were then stored for 4 weeks at 5°C±0.5°C under vacuum and compared with the control (0.1 MPa). RESULTS: HPP increased the shear force value, promoted moisture loss and lipid oxidation, induced surface paleness, stabilized pH during aging, and reduced bacterial load and growth. The shear force value of 500 MPa-treated samples remained higher than the control after aging, while no significant differences were found between the control and 300 MPa-treated samples. Degradation of inosinic acid and inosine occurred during pressurization, resulting in an increase in hypoxanthine content. However, the degradation rate in HPP-treated samples during aging was slower; therefore, inosinic acid and inosine content remained higher than in control samples. No significant differences were found in hypoxanthine content at the end of aging. HPP intensified the levels of hexanal, octanal, 2-methylbutanal, 3-methylbutanal, benzaldehyde, and 2,5-dimethylpyrazine in cooked-aged beef samples. CONCLUSION: HPP induced aroma development and delayed the degradation of inosinic acid. However, it also reduced the postmortem tenderization rate.

High pressure processing for dark-firm-dry beef: effect on physical properties and oxidative deterioration during refrigerated storage.

OBJECTIVE: Study on the application of high pressure processing (HPP) for dark-firm-dry (DFD) beef was conducted to observe whether HPP has any impact on physical properties and to evaluate oxidative deterioration during refrigerated storage under vacuum. METHODS: The longissimus lumborum muscles obtained from Friesian Holstein steers (33±0.5 months old) with 24-h postmortem pH higher than 6.0 were vacuum-packed and subjected to pressurization at 200, 400, and 600 MPa for 180 s at 15°C±2°C; the samples were then stored for 9 days at 4°C±1°C and compared with control (0.1 MPa). RESULTS: HPP increased meat pH by 0.1 to 0.2 units and the tenderness of cooked DFD beef significantly with no significant effects on meat texture profile. The stability of meat pH was well maintained during refrigerated storage under vacuum. No clear effects were found on the activity of catalase and superoxide dismutase, however, glutathione peroxidase activity was significantly reduced by high pressure. HPP and storage time resulted in aroma changes and the increasing amount of malondialdehyde and metmyoglobin relative composition. CONCLUSION: Although the increasing amount of malondialdehyde content, metmyoglobin formation and aroma changes in HPP-treated samples could not be avoided, HPP at 200 MPa increased L* and a* values with less discoloration and oxidative deterioration during storage.

Antioxidant Enzyme Activity, Iron Content and Lipid Oxidation of Raw and Cooked Meat of Korean Native Chickens and Other Poultry.

This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus) were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw and cooked samples. The activity of catalase (CAT) in the thigh meat was higher than that of the breast meat of three Korean native chickens and the broiler, respectively. The activity of glutathione peroxidase (GPx) in the uncooked thigh meat of three Korean native chickens was higher than that of the breasts. The breast meat of Woorimatdak and Pekin duck had higher superoxide dismutase (SOD) activity than the others, while only the thigh meat of Pekin duck had the highest activity. Cooking inactivated CAT and decreased the activity of GPx and SOD. The thigh meat of Woorimatdak, White Leghorn, Yeonsan ogye and Hyunin black contained more total iron than the breast meat of those breeds. The heme-iron lost during cooking ranged from 3.2% to 14.8%. It is noted that the thigh meat had higher thiobarbituric acid reactive substances values than the breast in all chicken breeds. Though Woorimatdak showed higher antioxidant enzyme activity and lower released-iron percentage among Korean native chickens, no differences were found on lipid oxidation. We confirm that the dark meat of poultry exhibited higher antioxidant enzyme activity and contained more iron than the white meat.

Effects of Replacing Pork Back Fat with Canola and Flaxseed Oils on Physicochemical Properties of Emulsion Sausages from Spent Layer Meat.

The objective of this study was to investigate the effects of canola and flaxseed oils on the physicochemical properties and sensory quality of emulsion-type sausage made from spent layer meat. Three types of sausage were manufactured with different fat sources: 20% pork back fat (CON), 20% canola oil (CA) and 20% flaxseed oil (FL). The pH value of the CA was significantly higher than the others (p<0.05). The highest water holding capacity was also presented for CA; in other words, CA demonstrated a significantly lower water loss value among the treatments (p<0.05). CA had the highest lightness value (p<0.05). However, FL showed the highest yellowness value (p<0.05) because of its own high-density yellow color. The texture profile of the treatments manufactured with vegetable oils showed higher values than for the CON (p<0.05); furthermore, CA had the highest texture profile values (p<0.05) among the treatments. The replacement of pork back fat with canola and flaxseed oils in sausages significantly increased the omega-3 fatty acid content (p<0.05) over 15 to 86 times, respectively. All emulsion sausages containing vegetable oil exhibited significantly lower values for saturated fatty acid content and the omega-6 to omega-3 ratios compared to CON (p<0.05). The results show that using canola or flaxseed oils as a pork fat replacer has a high potential to produce healthier products, and notably, the use of canola oil produced characteristics of great emulsion stability and sensory quality.

Distinguishing Aroma Profile of Highly-Marbled Beef according to Quality Grade using Electronic Nose Sensors Data and Chemometrics Approach.

Fat deposition in animal muscles differs according to the genetics and muscle anatomical locations. Moreover, different fat to lean muscle ratios (quality grade, QG) might contribute to aroma development in highly marbled beef. Scientific evidence is required to determine whether the abundance of aroma volatiles is positively correlated with the amount of fat in highly marbled beef. Therefore, this study aims to investigate the effect of QG on beef aroma profile using electronic nose data and a chemometric approach. An electronic nose with metal oxide semiconductors was used, and discrimination was performed using multivariate analysis, including principal component analysis and hierarchical clustering. The M. longissimus lumborum (striploin) of QG 1++, 1+, 1, and 2 of Hanwoo steers (n=6), finished under identical feeding systems on similar farms, were used. In contrast to the proportion of monounsaturated fatty acids (MUFAs), the abundance of volatile compounds and the proportion of polyunsaturated fatty acids (PUFAs) decreased as the QG increased. The aroma profile of striploin from carcasses of different QGs was well-discriminated. QG1++ was close to QG1+, while QG1 and QG2 were within a cluster. In conclusion, aroma development in beef is strongly influenced by fat deposition, particularly the fat-to-lean muscle ratio with regard to the proportion of PUFA. As MUFA slows down the oxidation and release of volatile compounds, leaner beef containing a higher proportion of PUFA produces more volatile compounds than beef with a higher amount of intramuscular fat.

Fatty acid profiles and flavour-related compounds of retorted Korean ginseng chicken soup (Samgyetang) affected by pre-treated black garlic extract.

OBJECTIVE: This study aimed to characterize the effect of pre-treated black garlic (BG) extracts addition into retorted Korean ginseng chicken soup (Samgyetang) on the fatty acid composition and flavour-related indexes. METHODS: Four different treatments; Samgyetang made with a 5% (w/w) addition of garlic (G), fresh BG (FBG), oven-dried BG (DBG), or encapsulated BG (EBG) extracts were developed and compared to negative control (NC) without any extract addition. Prepared samples were cooked via retorting at 121.1°C, 1.5 kgf/cm2 for 1 h. RESULTS: The BG treated samples were higher in C18:3n3 and C18:2n6 fatty acids, with thrombogenic index was 18% to 20% lower than the NC. EBG yielded the highest umamirelated nucleotides (5'-guanosine monophosphate and 5'-inosine monophosphate) and modified some free amino acid (alyne, phenylalanine and leucine) thus possessed the highest equivalent umami concentration among samples. Some individual aldehydes (pentanal, hexanal, and heptanal) were lower, while furans and volatile sulfur compounds were higher than the NC and G treatment group, indicating a potential suppression of unpleasant flavour alongwith the intensificiation of favourable flavour from the addition of BG extracts into retorted Samgyetang. CONCLUSION: Taken together, the synergistic results of this study indicate that incorportating suitable pre-treatment of BG extract could be of critical importance for the development of the retorted Samgyetang with improved flavour and functionalities.

The effects of lactic acid bacteria and yeasts as probiotics on the growth performance, relative organ weight, blood parameters, and immune responses of broiler: A meta-analysis.

Introduction: The number of publications in Scopus on this topic increased from less than 50 in 1995 to more than 250 in 2015. In other hand, Inconsistency in results about the correlation between yeast and lactic acid bacteria as probiotics has been evident since the early publications on use in broilers. Methods: A meta-analysis was conducted to determine relationship between lactic acid bacteria and yeast as probiotics to broiler diets on the growth performance, relative organ weight, blood parameters, and immune response of the broiler.  A database was designed based on published data that reported the use of probiotics on the broiler. The method used for selecting articles was based on the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) method. Articles selected were taken from PubMed, Web of science, Scopus, Google Scholar, and Science direct databases as well as individual. Results: The final database consists of 49 in vivo articles, 93 studies, and 225 treatments. The analysis statement in the system was a PROC MIXED procedure of SAS software. The level of probiotic increased (p <0.001) body weight, body weight gain, and feed intake of broiler. There was a reduction (p <0.01) on feed conversion ratio and mortality on the level probiotic given to broiler. Supplementation of probiotics in broiler diet increased (p <0.001) the weight of liver, spleen, gizzard, bursa of fabricius and carcass yield, while reduced (p<0.001) abdominal fat weight. The probiotic given increased the total of red and white blood cells (both at p < 0.001) but did not affect lymphocyte.  Discussion: It can be concluded the yeast act as supporting agent that serves lactic acid bacteria as probiotic increases the growth performance, relative organ weight, blood parameters, and immune response of the broiler.

Quality characteristics of retort samgyetang marinated with different levels of soy sauce and processed at different F0 values.

The aim of this study was to develop retorted samgyetang marinated with different levels of soy sauce and processed at different F0 (thermal death time at 121°C) values. The tested marinade series comprised different percentages of soy sauce in water (0%, 25%, and 50% [w/w]) containing a fixed concentration of sodium tripolyphosphate (0.3% [w/w]). Following marination, samgyetang was prepared and subjected to retort processing, until an F0 value of either 8 or 29 was achieved. Meat quality analysis of the breast meat, sensory evaluation, and aroma analysis were performed as indicators of acceptability. The meat pH decreased as the soy sauce content increased, regardless of the F0 value. The shear force value significantly decreased as the concentration of soy sauce increased, but increased as the F0 value increased (p < 0.05). Lipid oxidation was not affected by marination, but increased significantly as the F0 value increased (p < 0.05). The proportion of polyunsaturated fatty acids decreased significantly (p < 0.05) as the F0 value increased. The total alkane content decreased as the F0 value increased (p < 0.05). Changes in the total volatile sulfur compound and 2-butyl-1-octanol content were affected by soy sauce marination. Marination using 25% soy sauce and retort sterilization, until an F0 value of either 8 or 29 was achieved, improved the acceptability of samgyetang. Therefore, marination using 25% soy sauce and retort sterilization until an F0 value of 8 is the process recommended for developing a soy sauce-flavored, retorted samgyetang product of acceptable quality.

Fatty acid composition and quality properties of chicken sausage formulated with pre-emulsified perilla-canola oil as an animal fat replacer.

The potential use of an oil in water (o/w) emulsion made from perilla and canola oil in chicken sausage as an animal fat replacer was assessed. The (o/w) emulsion was made from 50% (wt/wt) perilla-canola oil mixture in a 30:70 ratio, 3.20% (wt/wt) polyglycerol polyricinoleate, 4.48% (wt/wt) soy protein isolate, 14% (wt/wt) inulin, and 28.32% (wt/wt) water. The sausages were manufactured with 60% (wt/wt) ground chicken breast, 20% (wt/wt) fat (beef tallow as a control), and 20% (wt/wt) ice water. Full replacement of animal fat with a perilla-canola oil (o/w) emulsion reduced the fat content and estimated calories but increased the moisture, protein, ash, and carbohydrate content. The proportion of α-linolenic acid (C18:3n3) was increased when animal fat was replaced with either a perilla-canola oil mixture or pre-emulsified perilla-canola oil, resulting in a lower n6 to n3 polyunsaturated fatty acid ratio than the control. The perilla-canola oil (o/w) emulsion improved emulsion stability and minimized cooking loss during sausage manufacturing. Higher L* value (lightness) and whiteness were observed in the sausages formulated with the perilla-canola oil mixture, followed by the pre-emulsified perilla-canola oil and the control. The perilla-canola oil (o/w) emulsion also increased the hardness but maintained an acceptable appearance, flavor, and overall impression similar to the control. The shelf life could be extended by vacuum packing and storing the cooked sausages formulated with a perilla-canola oil (o/w) emulsion for 30 D at 2 ± 1°C. Pre-emulsified perilla-canola oil could be used to replace animal fat in reduced-fat chicken sausage manufacture.

Formula Optimization of a Perilla-canola Oil (O/W) Emulsion and Its Potential Application as an Animal Fat Replacer in Meat Emulsion.

The formulation of an oil/water (o/w) emulsion made up of a mixture of perilla oil and canola oil (30/70 w/w) was optimized using a response surface methodology to find a replacement for animal fat in an emulsion-type meat product. A 12 run Plackett-Burman design (PBD) was applied to screen the effect of potential ingredients in the (o/w) emulsion, including polyglycerol polyricinoleate (PGPR), fish gelatin, soy protein isolate (SPI), sodium caseinate, carrageenan (CR), inulin (IN) and sodium tripolyphosphate. The PBD showed that SPI, CR and IN showed promise but required further optimization, and other ingredients did not affect the technological properties of the (o/w) emulsion. The PBD also showed that PGPR played a critical role in inhibiting an emulsion break. The level of PGPR was then fixed at 3.2% (w/w total emulsion) for an optimization study. A central composite design (CCD) was applied to optimize the addition levels of SPI, CR or IN in an (o/w) emulsion and to observe their effects on emulsion stability, cooking loss and the textural properties of a cooked meat emulsion. Significant interactions between SPI and CR increased the cooking loss in the meat emulsion. In contrast, IN showed interactions with SPI leading to a reduction in cooking loss. Thus, CR was also removed from the formulation. After optimization, the level of SPI (4.48% w/w) and IN (14% w/w) was validated, leading to a perilla-canola oil (o/w) emulsion with the ability to replace animal fat in an emulsion-type meat products.

Effect of Ground Chopi (Zanthoxylum piperitum) on Physicochemical Traits and Microbial Community of Chicken Summer Sausage during Manufacture.

Changes in microbial community and physicochemical traits of chicken summer sausage made from spent layer thigh added with different level (0%, 0.1%, 0.3%, and 0.5% w/w) of ground chopi (Zanthoxylum piperitum) during manufacture were analyzed. The microbial community was profiled and analyzed by sequencing 16S rRNA gene using Illumina MiSeq. Samples were taken from raw sausage batter, after 15 h of fermentation, 8 h of cooking including cooling down, and 7 d of drying. The final pH of the sausage was reduced by the addition of ground chopi. However, no clear effect on water activity was observed. Ground chopi inhibited the development of red curing color after fermentation as it exhibited antimicrobial effect. However, the effect on species richness and microbial composition after cooking was unclear. Ground chopi delayed lipid oxidation during manufacture and the effect was dependent on the addition level. Fermentation reduced the species richness with a dominancy of lactic acid bacteria. The profile of microbiota in the raw batter was different from other stages, while the closest relationship was observed after cooking and drying. Proteobacteria was predominant, followed by Firmicutes and Bacteroidetes in raw samples. Firmicutes became dominating after fermentation and so forth, whereas other predominant phylum decreased. At genus level, unclassified Lactobacillales was the most abundant group found after fermentation and so forth. Therefore, the overall microbial composition aspects were mainly controlled during fermentation by the abundance of lactic acid bacteria, while bacterial counts and lipid oxidation were controlled by cooking and the addition of ground chopi.

Effect of mixed hay supplementation during fattening on carcass traits and meat quality of Hanwoo steers.

BACKGROUND: This study was aim to observe the effects of feeding mixed local hay (MH) consisted of 55% orchard grass (Dactylis glomerata L.), 35% tall fescue (Festuca arundinacea) and 10% red clover (Trifolium pratense) to Hanwoo steers on performance, carcass characteristics and meat quality (longissimus thoracis) compared with feeding imported timothy hay (TH) and local rice straw (RS). RESULTS: Although no significant effects were found on animal performance and carcass yield grade, the carcasses of MH group had higher marbling score and quality grade than those of RS and TH group (P < 0.05). Therefore, higher fat content (P < 0.001), lower shear force and hardness value in the beef of MH group than that of other groups were observed. Furthermore, the beef of MH group had higher CIE a* value (redness) than that of other groups and feeding MH to Hanwoo steers lowered n-6 to n-3 fatty acids ratio in beef. CONCLUSIONS: Mixed hay provided benefits on meat quality and could be used for Hanwoo fattening program.

Effects of Gaseous Ozone Exposure on Bacterial Counts and Oxidative Properties in Chicken and Duck Breast Meat.

The effects of gaseous ozone exposure on the bacterial counts and oxidative properties were evaluated in duck and chicken breast fillets, which were stored under a continuous flux of gaseous ozone (10×10(-6) kg O3/m(3)/h) at 4±1℃ for 4 d. The ozone generator was set to on for 15 min and off for 105 min, and this cyclic timer was set during storage. Ozone effectively reduced the growth of coliform, aerobic and anaerobic bacteria in both chicken and duck breast. However, lipid oxidation occurred faster in duck breast than chicken breast with higher degree of discoloration, TBARS value, and antioxidant enzyme (glutathione peroxidase and catalase) activity decline rates. It is concluded that ozone effectively controlled the growth of bacteria in both chicken and duck breast with less effects on oxidative deterioration in chicken breast.

Correlation between Antioxidant Enzyme Activity, Free Iron Content and Lipid Oxidation in Four Lines of Korean Native Chicken Meat.

This study was conducted to observe the association between antioxidant enzyme activity, free iron content and lipid oxidation of Korean native chicken (KNC) meat during refrigerated storage. Four lines of KNC (Yeonsan ogye, Hyunin black, Hoengseong yakdak and Hwangbong) were raised under similar conditions. A total of 16 roosters were randomly sampled and slaughtered at the age of 12 mon. The breast and thigh meats were stored aerobically for 10 d at 4℃. Although thigh meat had higher antioxidant enzyme activity, it was more susceptible to lipid oxidation and released more iron during storage than breast meat. Aerobic refrigerated storage for 10 d significantly decreased the activity of antioxidant enzymes and increased the amount of free iron and malondialdehyde. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were negatively correlated with lipid oxidation, whereas that of catalase was not. The amount of free iron was positively associated with lipid oxidation. We concluded that chicken line did not affect strongly on antioxidant enzyme activity and lipid oxidation in breast meat of KNC. However, the thigh meat of Hwangbong and Hyunin black had higher SOD and GSH-Px activity, respectively, and lower malondialdehyde contents than that of other chickens. SOD, GSH-Px and free iron play significant roles in meat lipid oxidation during refrigerated storage.