• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.22 no.3
• /
• pp.95-102
• /
• 2016

This study investigated the effects of the oxygen permeability of vacuum packaging film and the storage temperature on the quality and shelf life of Hamburg steaks during storage for 14 days. Control samples (C) were packaged in a polyamide/polyethylene (PA/PE) film and stored at $5^{\circ}C$. Treatment samples were either packaged in an ethylene vinyl alcohol/polyethylene (EVOH/PE) copolymer film and stored at $5^{\circ}C$ (T1), and in a PA/PE film and stored at $-18^{\circ}C$ (T2). The initial total plate count (TPC) was 3.6 log cfu/g. In T1 samples, TPC and Brochothrix thermosphacta counts were increased, similar to those in C samples, whereas Pseudomonas spp. counts were significantly lower than those in C samples during storage. Over the storage period, the volatile basic nitrogen values increased most rapidly in C samples, followed by T1 and then T2 samples. The values of thiobarbituric acid reactive substances steadily increased in all samples during storage. The colour parameters were not significantly different among the samples during storage. T1 samples maintained sensory qualities in flavour and off-odour parameters for two days longer than C samples did. At day 12, T2 samples were evaluated as being below the marketability score of 5.0 for texture. In conclusion, using high oxygen barrier films like EVOH/PE copolymer for packaging Hamburg steaks could extend the sensory qualities in view of flavour and off-odour during chilled storage. However, frozen storage at $-18^{\circ}C$ is recommended when the storage period is extended beyond 14 days at $5^{\circ}C$.

• Food Science of Animal Resources
• /
• v.30 no.2
• /
• pp.277-285
• /
• 2010

The objective of this study was to manufacture spent layer chicken meat products by natural freeze-drying. The spent layers of chickens that were slaughtered at 80 wk were obtained from a local slaughter house and separated into two halves of carcasses. The samples were divided into the following groups: 1) control (non-curing), 2) curing, and 3) curing with 2% trehalose before drying. The cured meats were placed at $2^{\circ}C$ for 7 d and then transferred to a natural drying spot located in Injae City, Gangwondo, Korea. The experiment was conducted from January to March in 2008. The average temperature, RH, and wind speed were $-1.5^{\circ}C$, 63%, and 1.8 m/sec, respectively. The cured treatments showed higher pH, lower Aw and lower shear force value compared with the control. Based on the results of TBARS (2-thiobarbituric acid reactive substances) level and volatile basic nitrogen value, lipid oxidation and protein deterioration were inhibited in curing treatments during drying. Trehalose acted as a humectant because it maintained a lower water activity despite the relatively higher moisture content during drying. The polyunsaturated fatty acids content and sensory attributes were higher in cured treatments than in the control during drying. Most of the bacterial counts in the treated groups were lower by 2 Log CFU/g after 1 mon of drying, and Salmonella spp. and Listeria spp. were not found in any treatment. There was also no microbial safety problem associated with dried meat products. Based on the results of this experiment, dried meat products could be manufactured from precured spent layer chickens by natural freeze-drying during winter.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.6
• /
• pp.1058-1064
• /
• 2002

The purpose of this study was to investigate the effects of green tea on hepatic antioxidative defense system and recovery of muscle fatigue in rat after aerobic exercise. Male Sprague-Dawley rats weighing 150$\pm$ 10 g were randomly assigned to one normal (N) group and aerobic exercise training groups. Exercise training groups were classified into two groups: training (T) group and green tea (TG) group which were supplemented the distilled water and green tea extracts by dringking water during experimental periods, respectively. The experimental rats in exercise training groups (T and TG) ran on a treadmill 30 min/day at a speed of 28 m/min (7% incline) 5 days/week or were cage confined (Normal group) for 4 weeks. And rats were sacrificed with an overdose of pentobarbital injection just after running. Hepatic xanthine oxidase (XOD) activities were not significantly different among three groups. The activity of superoxide dismutase (SOD) in T group was no significant difference from N group, but those of TG groups were significantly increased, compared with that of T group. Hepatic glutathione peroxidase (GSHpx) activites of TG groups showed a similar tendency to that of normal group, but it was increased to 20% in TG group, compared with normal group. The reduced glutathione (GSH) contents in liver was not significantly different from that of any three group. The oxidized glutathione (GSSG) contents in T group was increased to 69%, compared with the normal group, but TG group significantly decreased, compared with the T group. The ratio of GSH/GSSG in liver of T group was lower than that of normal group, but those of TG group was a similar tendency to that of normal group. Contents of thiobarbituric acid reactive substance(TBARS) in T group was increased to 52%, compared with that of normal group but those of TG group were recovered the normal level. Contents of hepatic glycogen in T group were decreased to 23% compared with those of normal group, while that of TG group was the same as normal levels. The contents of serum lactic acid in T group were increased to 261%, compared with normal group, but those of TG group maintained the normal level by green tea supplementations. In conclusion, the effects of green tea in exercise training rats would appear to reduce peroxidation of tissue as an antioxidative defense mechanism and promote recovery of muscle fatigue.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.4
• /
• pp.575-580
• /
• 1996

The purpose of this study was to investigate the effect of dietary vitamin E levels on the enzymes such as superoxide dismutase(SOD), glutathione peroxidase(GSH-Px) and glutathione S-transferase (G57) involved in antioxidative defense system and lipid peroxidation in brain of cadmium administered rats. Sprague-Dawely male rats weighing $60\pm5g$ were divided into control and experimental groups. The experimental groups were divided into Cd-0E(vitamin E free diet), Cd-40E(40mg vitamin E/kg diet) and Cd-400E(400mg vitamin E/kg diet) according to the level of vitamin E supplementation. After each group was fed diet ad libitum for 2 or 4 weeks, 2.5mg cadmium per kg body weight was injected intraperitoneally once a day for 4 days. The rats were sacrificed for examination on the next day after the last injection of cadmium. The results are as follows: SOD activities of rat brain were lower in Cd-0E, but had a similar tendency to Cd-40E, Cd-400E groups compared with control group. GSH-Px acivities of rat brain were decreased in Cd-400E, Cd-40E and Cd-0E groups. GST activities of rat brain were decreased in Cd-0E, Cd-40E groups and not significantly different in Cd-400E compared with control group. Thiobarbituric acid reactive substances(TBARS) of rat brain was increased in Cd-0E, Cd-40E, Cd-400E in that order, TBARS was lower in Cd-40E, and Cd-400E by 28.8% and 44%, respectively, than Cd-0E group. The present result suggests that high level of dietary vitamin E protects against lipid peroxidative damage in rat induced by cadmium.

• Journal of Animal Science and Technology
• /
• v.47 no.5
• /
• pp.837-850
• /
• 2005

This study was conducted to investigate the changes of quality characteristics on seasoned pork with Korean traditional 4 types seasoning such as soybean sauce(T1); Kimchi sauce(T2); pickled shrimps sauce(T3); onion sauce(T4). The seasoned samples were aged at 10±1℃ for 13 days. The results obtained were as follows; Except for T2, pH of treatments were significantly decreased(P<0.05) as aging period increased. Salinity(%) and saccharinity(%) of seasoned meat were tended to increased during aging period. Thiobarbituric acid reactive substances(TBARS) were increased significantly during storage in all treatment(P<0.05). T4 showed the highest TBARS among the all treatment groups. Volatile basic nitrogen(VBN) values of all treatments were significantly increased(P<0.05) as storage period increased. There were no significant differences in water holding capacity(WHC) among the all treatments, and those values were not changed by the passage of storage days. Shear force values of all treatments were tended to decreased by the passage of storage days. In surface color, the values of L*, a* and b* showed a tendency of increasing value along the storage days. The values of a* and b* of T2 were significantly higher than other treatments during aging period(P<0.05). In inner color, a* and b* values of T2 were significantly higher than those of other treatments during aging period(P<0.05). In the sensory evaluation of cooked meat, T3 treatment resulted in lower score in aroma, flavor, tenderness, juiciness and overall acceptability. The number of total plate counts and Lactobacilli spp. tended to increase with storage in all treatments group. The numbers of Escherichia coli were not changed by the passage of storage time.

• Food Science and Preservation
• /
• v.24 no.1
• /
• pp.84-92
• /
• 2017

Chicken breast jerky (CJ) was prepared by drying chicken breast at $50^{\circ}C$ for 9 hrs after marinating it in a various sweetening sauce including white sugar (WS), brown sugar (BS), rice syrup (RS), fructooligosaccharide (FO), pineapple concentrate (PC), Rubus coreanus extract (RCE), or honey (H), and its physicochemical and sensory properties were investigated. The CJ was found to contain 22.5-25.0% moisture, 41.0-46.6% protein, and 0.4-1.0% fat, which indicates that it could serve as a high-protein and low-fat snack. The type of sweeteners significantly affected the yield, pH, total viable cell count, and water activity of the CJ, showing ranges of 40.9-50.1%, 5.2-5.9, $2.5-6.2{\times}10^4CFU/g$, and 0.74-0.81, respectively. Both the water activity and pH were the lowest in CJ-RCE where of the highest in CJ-WS. The cohesiveness, springiness, and chewiness of the CJ significantly differed depending on the type of sweeteners (p<0.05). CJ-RCE showed the best taste and overall acceptability in a sensory test. After storage at $50^{\circ}C$ for 2 weeks, thiobarbituric acid reactive substance (TBARS) content (58.3 malondialdehyde (MDA) mg/kg) of CJ-RCE was much lower than those of control beef (75.6 MDA mg/kg) and pork jerky (98.0 MDA mg/kg), showing the good oxidative stability of CJ-RCE. Overall, marination in RCE sauce was suitable for the preparation of CJ with good quality in terms of its water activity, fat and protein contents, sensory property and oxidative stability.

• Korean Journal of Poultry Science
• /
• v.40 no.1
• /
• pp.1-9
• /
• 2013

This study was investigated the effects of dietary supplementation of Yacon by-product powder on performance, pH, total phenol contents, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, TBARS, WHC, shear force, meat color, and sensory evaluation of chicken thigh meat. Broiler chicks were fed diets for five weeks containing 0% Yacon by-products powder (Control), 0.5% Yacon by-products powder (T1), 1.0% Yacon by-products powder (T2), and 2.0% Yacon by-products powder (T3). There was no significant difference in performance among treatments, but mortality was decreased in diets by the supplementation of Yacon by-product powder than that of control. The total cholesterol, LDL-cholesterol and triglyceride of control were higher than treatment groups and HDL-cholesterol and glucose of control was lower than treatment. The pH and TBARS were significantly decreased by the supplementation of Yacon by-product powder compared to the control (P<0.05). The total phenol contents and DPPH radical scavenging activity were significantly increased by the supplementation of Yacon by-product powder compared to those of the control group (P<0.05), and especially, T3 was significantly (P<0.05) more effective in improving freshness compared to other treatment groups. The WHC (water holding capacity) and shear force were not significantly different. CIE $L^*$ and $a^*$ value of treatment groups showed significantly higher value compare to the control, however, no difference in the CIE $b^*$ values was observed among treatment groups. In conclusion, a supplementation of Yacon by-product powder was effective in decreasing pH and TBARS (thiobarbituric acid reactive substance), and increasing total phenol contents and DPPH radical scavenging activity.

• Food Science of Animal Resources
• /
• v.33 no.6
• /
• pp.796-805
• /
• 2013

This study was conducted to investigate the relationship between quality factors and freshness or palatability of Hanwoo beef according to storage condition. The drip loss, cooking loss, volatile basic nitrogen (VBN), thiobarbituric acid reactive substance (TBARS), total viable counts (TVC) and sensorial characteristics of Hanwoo beef (raw and cooked) were investigated during storage for 36 d at 0 and $10^{\circ}C$. The drip loss, cooking loss, VBN, and TBARS were increased during storage period. The correlation between these factors and freshness was shown to be highly significant at both $10^{\circ}C$ than $0^{\circ}C$. Especially, correlation of between the cooking loss and freshness of Hanwoo beef showed high significance (p<0.01) at higher storage temperature. The correlation coefficient between factors such as VBN, cooking loss, and TVC and palatability were decreased with increased storage temperature. As a statistical analysis result, a multiple regression equation of $Y_1=10.768-0.706X_1$ (Drip loss) with $R^2=0.87$ was obtained for freshness evaluation of Hanwoo beef. Also, multiple regression with drip loss ($X_1$) and TVC ($X_5$) increased the coefficient of determination for sensorial palatability ($Y_2$) to $R^2=0.95$ with a regression equation of $Y_2=9.702-0.438X_1(Drip\;loss)-0.232X_5(TVC)$.

• Food Science of Animal Resources
• /
• v.31 no.2
• /
• pp.296-303
• /
• 2011

This study was conducted to determine the effects of stevia (Stevia rebaudiana Bertoni) and charcoal supplementation on meat quality traits in finishing pigs. A total of 420 pigs (LYD) were randomly allocated into seven treatments with three replications. The dietary treatments were T1 (control, basal diet), T2 (basal diet+0.3% stevia), T3 (basal diet+0.6% stevia), T4 (basal diet+0.3% charcoal), T5 (basal diet+0.6% charcoal), T6 (basal diet+0.3% stevia+0.3% charcoal), and T7 (basal diet+0.6% stevia+0.6% charcoal). Pigs were slaughtered conventionally on each marketing day and chilled overnigth. At 24 h postmortem, the Longissimus muscle from left side between the 6th and 14th rib was removed for the meat quality traits. The T6 group showed a higher pH, water holding capacity (p<0.05), and lower drip loss (p<0.05) than those in the T1 group. The T6 group showed lower (p<0.05) $L^*$ (lightness) and $b^*$ (yellowness) values and higher $a^*$ (redness) color value than those in the T1 group, resulting in a redder surface meat color. In the subjective evaluation, marbling and color scores improved in the T6 group compared to those in the other treatments. In the panel test, the T6 group tended to have higher tenderness and juiciness scores than those in the T1 group. In the storage characteristics, all treatments showed similar 2-thiobarbituric acid and volatile basic nitrogen values as well as total microbial counts during 7 d of cold storage. As a result, dietary supplementation with 0.3% stevia and 0.3% charcoal showed the highest meat quality traits and storage characteristics in finishing pigs.

• Journal of the East Asian Society of Dietary Life
• /
• v.22 no.2
• /
• pp.298-304
• /
• 2012

This study was carried out to investigate the effects of various thawing methods on the physical and microbiological properties of frozen pork. The frozen pork was thawed using four methods: refrigerator, cold water, room temperature, and microwave oven. Changes in physicochemical properties of thawed pork were analyzed by measuring color, pH, thawing loss and thiobarbituric acid reactive substances (TBARS) values. Changes in the microbiological properties of thawed pork were analyzed by counting total aerobic bacteria and coliform group. L values of thawed pork were significantly increased by all thawing methods for normal thawing time except the uncooked portion of thawed pork via a microwave. However, the a value decreased in pork thawed by all thawing methods. pH values significantly increased in the pork thawed by microwave and by applying two times the normal thawing time. After thawing, thawing loss was highest in the pork thawed at room temperature for two times the normal thawing time. In addition, TBARS values also increased in the pork thawed in a refrigerator and at room temperature for two times the normal thawing time. The total aerobic bacteria count significantly increased in the case of microwave thawing for normal thawing time and it also increased in the pork thawed in a refrigerator and at room temperature for two times the normal thawing time. These results demonstrate that refrigeration and cold water thawing are the most suitable for frozen pork, and that excess thawing should be avoided.