Korean Journal for Food Science of Animal Resources最新文献

Salmonellosis caused by chicken consumption has been a critical issue in food safety worldwide, including in Korea. The probability of illness from consumption of chicken was simulated in study, based on the recipe of Dakgalbi, a commonly eaten chicken dish in Korea. Additionally, the processing stage at slaughterhouses to decrease Salmonella concentration in broilers was modeled to explore its effect on the likelihood of illness. A Monte Carlo simulation model was created using @RISK. Prevalence of Salmonella in chickens at the retail stage was found to be predominantly important in determining the probability of illness. Other than the prevalence, cooking temperature was found to have the largest impact on the probability of illness. The results also demonstrated that, although chlorination is a powerful tool for decreasing the Salmonella concentration in chicken, this effect did not last long and was negated by the following stages. This study analyzes the effects of variables of the retail-to-table pathway on the likelihood of salmonellosis in broiler consumption, and also evaluates the processing step used to decrease the contamination level of Salmonella in broilers at slaughterhouses. According to the results, we suggest that methods to decrease the contamination level of Salmonella such as chlorination had little effect on decreasing the probability of illness. Overall, these results suggest that preventing contamination of broiler with Salmonella must be a top priority and that methods to reduce the concentration of Salmonella in broilers at slaughterhouses hardly contribute to safe consumption of Salmonella-contaminated chicken.

The aim of this study was to investigate the effects of dry-aging (DA) and the cooking process on the myofibril protein functionalities and in vitro digestibility of proteins in beef loin. Six sirloins from beef were dry-aged for 28 d, and the control group (n=6) was analyzed 2 d postmortem for this study. Dimensional changes (reduction of thickness and surface shrinkage) after cooking were significantly greater in the control group than the DA group, whereas the shear force of the DA group was significantly lower than that of the control. Effect of cooking on aggregation, hydrophobicity, and in vitro digestibility were significantly higher in the DA group than in the control. After cooking, the protein in DA sirloins was more oxidized than in the control samples. According to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis result, the low molecular weight bands (below 17 kDa) increased in the DA group, finding that the protein characteristics of dry-aged beef was affected by cooking.

Changes in the physicochemical properties of ready-to-feed liquid infant formula (LIF) stored at different temperatures (10, 20, 30, and 40°C) for 6 mon, focusing on 5-hydroxymethylfurfural (HMF) content, color, pH, fat globule size distribution, and rheological properties were determined. The HMF content increased with storage time, and LIF stored at 40°C had a higher HMF content than that of LIF stored at 10°C. The lightness (L*) decreased while redness (a*) and yellowness (b*) increased with increasing HMF content. The fat globule size and pH of LIF stored at 10°C did not change. However, in the case of LIF stored at 30°C and 40°C, the fat globule size increased and the pH decreased during storage for 6 mon. LIF stored at 40°C had a higher apparent viscosity (η_a,10) than that of LIF stored at 10°C, and the shear-thinning behavior of LIF stored at higher temperature was stronger than that of LIF stored at low temperature. The physicochemical changes of LIF during storage were accelerated by Maillard reaction (MR) at higher storage temperatures. Therefore, even if LIF is aseptically manufactured, we recommend that sterilized LIF should be stored at low temperature in order to minimize quality changes during storage.

The aim of this study was to determine meat quality characteristics and fatty acid composition of Korean native black goats (KNBG) finished on intensive feeding of alfalfa (ALF) and conventional feeding of commercial concentrate pellets (CCP) with low-energy common grasses. Ten KNBG (12 months old) were divided into two groups and subjected to either ALF or CCP treatments. The goats were slaughtered after 6 months of feeding with experimental diets to investigate meat quality characteristics and fatty acid compositions of longissimus lumborum muscle. There were no significant differences in proximate chemical composition, collagen, or myoglobin content between ALF and CCP groups of goats. Meat color, water-holding capacity, or tenderness was not significantly different between the two groups either. However, proportions of monounsaturated fatty acids and polyunsaturated fatty acids were significantly (p<0.05) different between the two groups. The proportion of oleic acid was significantly (p<0.05) higher in ALF goat whereas proportion of linoleic and arachidonic acids were significantly (p<0.05) higher in CCP goat. Results suggest that KNBG finished with intensive feeding of alfalfa could produce goat meat with desirable fatty acids for human diets.

Various amounts of buckwheat powder (0%, 1%, 2%, and 3%) were added to emulsion-type pork sausages. The effects of buckwheat powder on the physicochemical characteristics of the emulsion type sausages, including proximate composition, cooking yield, viscosity, pH, instrumental color, texture profile analysis (TPA), and sensory evaluation, were determined. Increased levels of added buckwheat powder led to higher moisture (p<0.05), ash content (p<0.05 or >0.05), and cooking yield (p<0.05). However, the protein and fat contents of the sausage samples were lower (p<0.05) with higher levels of added buckwheat powder. The instrumental color and pH values were affected by the addition of buckwheat powder, which has a pH of 6.1 and associated color coordinates of L*=75.0, a*=1.3, and b*=8.7. Meat batter with 3% buckwheat powder was shown the highest (p<0.05) viscosity indicating great formation of emulsion. There were no significant differences in the TPA among the treated samples. The viscosity value increased with increasing cooking yield in the batter (r²=0.7283) i.e. the correlation coefficient between the two measurements was very high and positive. For sensory traits except for tenderness, the highest scores (p<0.05) was detected on sausages with 3% added buckwheat powder by a panel. These results suggest that the addition of 3% buckwheat powder to emulsion-type sausages produces a more beneficial meat product, with a lower fat content, greater formation of emulsion and no adverse effects on sensory properties.

Although bacteriocins with anti-listerial activity have been isolated from a wide variety of lactic acid bacteria, little is known about those from Leuconostoc lactis, a heterofermentative bacterium that produces diacetyl and exopolysaccharides in dairy foods. In this study, an anti-listerial bacteriocin was isolated from Leuc. lactis SD501 and characterized. It was particularly potent against Listeria monocytogenes and also inhibited Enterococcus faecalis. Anti-listerial activity reached a maximum during the early stationary phase and then decreased gradually. The anti-listerial substance was sensitive to proteinase K and ɑ-chymotrypsin, confirming its proteinaceous nature. Its activity remained stable at pH values ranging from 1 to 10. In addition, it was strongly resistant to high temperatures, retaining its activity even after incubation for 15 min at 121℃. The apparent molecular mass of the partially purified anti-listerial bacteriocin was approximately 7 kDa. The characteristics of the SD501 bacteriocin, including its small molecular size (<10 kDa), strong anti-listerial activity, wide pH stability and good thermostability, indicate its classification as a Class IIa bacteriocin.

The eggshell, which is a complex and highly ordered structure, is very important factor for food safety and egg marketing. This study investigated the changes in eggshell structure and shell components in relationship to hen age. For this study, we examined the histological change of the endometrium of the 30-, 60-, and 72-wk-old commercial layers, and analyzed the ultrastructure and ionic composition of their eggshells. The results showed that histological deformation, fibrosis, atrophy and elimination of micro-villi in the uterus endometrium were found through microscopic observation that was associated with increasing hen age. Concentration of blood-ion components such as Ca²⁺, Na⁺, K⁺, and Cl^- ions did not change with age. Along with the results from the ultrastructure analysis of the eggshell, the palisade layer ratio and the density of mammillary knobs were significantly decreased in older hens. In addition, the type B mammillary knobs were frequently observed with increasing hen age. In the mineral element assay from the eggshell, Ca²⁺, S^2-, and Co²⁺ significantly decreased with increasing hen age, whereas Na⁺, K⁺, and V²⁺ significantly increased. Therefore, the damages of endometrial tissue inhibit the processes of ion transmission and the crystallization of eggshell formation, resulting in a large and non-uniform mammillary knob formation. This means the conditions of endometrial cells affect the formation of the eggshell structure. In conclusion, hen aging causes the weakness of the eggshell and degrades the eggshell quality.

The crust that inevitably forms on dry-aged beef is usually trimmed and discarded before sale. The aim of this study was to explore methods for utilizing this crust in processed meat products. Four sirloins were dry-aged for 28 d at 4℃ (75% relative humidity). The crust obtained from the surface of the sirloins after completion of dry aging was lyophilized. Patties were prepared without added crust (control) or with 5% w/w crust, aerobically packaged, and stored at 4℃ for 7 d. Electronic nose analysis indicated that the volatile profile differed significantly between the patties with and without crust. Compared to the control patties, patties containing crust had higher flavor, tenderness, juiciness, and acceptability scores in a sensory panel evaluation (all p<0.05). In addition, patties with crust were less hard, gummy, and chewy than the control patties after 3 and 7 d of storage (all p<0.05). The number of total aerobic bacteria was higher in raw patties with crust than in the control patties during the storage (p<0.05). However, no pathogens were detected. 2-Thiobarbituric acid reactive substance values of patties containing crust were significantly lower than those of control patties after 2 and 6 d of storage (both p<0.05). Thus, crust from dry-aged beef can enhance the flavor by providing beefy and palatable flavor without a long period of dry aging.

This study aimed to investigate the use of golden thread extract (GTE), clove extract (CE), and commercially available nitrite for retarding lipid and protein oxidation and for maintaining color stability and sensory attributes in beef patties stored at 4℃. GTE, CE, and nitrite treatment samples were found to be efficient in retarding lipid oxidation as all three treatments resulted in low thiobarbituric acid reactive substance (TBARS) content (p<0.05). By using GTE, CE, and nitrite into beef patties, protein oxidation was not developed. Incorporation of GTE and CE into beef patties maintained color stability by protecting against the decrease of L*, a*, b*, chroma, and hue angle values and exhibited significant influence on sensory characteristics, including color and odor of beef patties (p<0.05). Compared to commercially available nitrite, GTE and CE were more effective as antioxidants for inhibiting lipid oxidation, and preserving color stability of fresh beef patties. The study indicated that GTE and CE could be utilized efficiently to extend the shelf life of beef patties.

The present study aimed at evaluating the utilization possibility of encapsulated probiotic Bifidobacterium longum for production of functional fermented sausages. The B. longum isolated from the feces samples of healthy Korean infants encapsulated with glycerol as a cryprotectant was used for fermented sausages production as a functional bacterial ingredient, and its effect was also compared with those inoculated with commercial starter culture (CSC). Results showed that most inoculated encapsulated B. longum (initial count, 5.88 Log CFU/g) could survive after 4 days fermentation (5.40 Log CFU/g), and approximately a half (2.83 Log CFU/g) of them survived in the products after 22 days of ripening. The products inoculated with encapsulated B. longum presented the lowest lipid oxidation level, while had higher total unsaturated fatty acid content and more desirable n-6/n-3 fatty acids than those inoculated with CSC or non-inoculated control. Moreover, the odor and taste scores in the samples made with B. longum were comparable to those in the treatment with CSC. The inoculation with the B. longum had no effects on the biogenic amine contents as well as did not cause defects in color or texture of the final products. Thus, the encapsulation could preserve the probiotic B. longum in the meat mixture, and the encapsulated B. longum could be used as a functional ingredient for production of healthier fermented meat products.