• 한국축산식품학회지
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• 제42권6호
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• pp.953-967
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• 2022

The objective of this study was to determine effects of aging methods (wet-aged, dry-aged, and packaged dry-aged) during 60 d on quality traits and microbial characteristics of beef. Wet-aged beef was packed by vacuum packaging and stored in a 4℃ refrigerator. Dry-aged beef was used without packaging. Packaged dry-aged beef was packaged in commercial bags. Dry-aged and packaged dry-aged samples were stored in a meat ager at 2℃-4℃ with 85%-90% relative humidity. Meat color, crust thickness, aging loss, cooking loss, Warner-Bratzler shear force (WBSF), texture profile analysis, Torrymeter, meat pH, water activity, volatile basic nitrogen (VBN), thiobarbituric acid reactant substances (TBARS), and microbial analysis were measured or performed every 15 d until 60 d of aging time. Meat color changed significantly with increasing aging time. Differences in meat color among aging methods were observed. Aging losses of dry-aged and packaged dry-aged samples were higher than those of wet-aged samples. Wet-aged beef showed higher cooking loss, but lower WBSF than dry-aged and packaged dry-aged beef. VBN and TBARS showed an increasing tendency with increasing aging time. Differences of VBN and TBARS among aging methods were found. Regarding microbial analysis, counts of yeasts and molds were different among aging methods at the initial aging time. Packaged dry-aged and dry-aged beef showed similar values or tendency. Significant changes occurred during aging in all aging methods. Packaged dry aging and dry aging could result in similar quality traits and microbial characteristics of beef.

• 농업과학연구
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• 제49권4호
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• pp.983-993
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• 2022

The purpose of this study is to provide information on a forest healing environment using the analysis of nature volatile organic compounds (NVOCs) and thermal comfort in Chungnam National University Experimental Forest, with the aim of using the Experimental Forest as a healing environment for health promotion. We analyzed NVOCs and thermal comfort of Chungnam National University Experimental Forest measured on September 12^th, 2021. As a result of the NVOC analysis, a total of seven substances were detected, mainly including alpha pinene and beta pinene. The detection amount for each time period was highest at the time of sunset. The thermal comfort was analyzed by time-dependent changes and changes according to clothing and exercise amount. The results showed that the predicted mean vote of the experimental forest is within the range of 'slightly cool' and 'slightly warm' sensation, and thus a comfortable thermal environment could be controlled by the amount of clothing and activity. Based on the analysis, this study provides information on the healing environment of the experimental forest at Chungnam National University. It also indicates that the forest can be used as a health promotion and healing environment with thermal comfort by composing a physical activity program of appropriate intensity for each time period.

• 한국축산식품학회지
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• 제43권3호
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• pp.454-470
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• 2023

This study analyzed the microbiological (Lactobacillus spp., Staphylococcus spp., mold, yeast, aerobic bacteria) and physicochemical properties [pH, salinity, water activity, volatile basic nitrogen (VBN), and thiobarbituric acid reactive substances]. The starters were used by mixing Debaryomyces hansenii separated from Korean Doenjang (D) and fermented sausage (S). The starter was inoculated with dry-cured ham and aged for 6 weeks at 20℃ and 25℃, respectively. The aerobic bacteria, Lactobacillus spp., and Staphylococcus spp. of D, S, and DS treatment showed significantly higher values at 25℃ than at 20℃. Among them, S25 treatment showed a high tendency. At week 6, the mold of the S25 treatment was significantly higher than the S20 treatment, and the yeast was higher in 25℃ than 20℃ (p<0.05). The pH of all treatment groups increased with the aging period. Compared with that at 25℃, the pH was significantly higher at 20℃ (p<0.05). The water activity showed a significant decrease as the aging period increased, and the treatment of D25, S20, and DS20 showed a significantly higher value at week 6 (p<0.05). Compared with that at 20℃, the VBN content was higher at 25℃. At week 6, the VBN contents of the C20, S25, and DS25 groups were higher than those of the other treatment groups. Therefore, inoculation of D. hansenii separated from fermented sausage produced in Korean starter at 25℃ is expected to improve the safety of harmful microorganisms and physiochemical properties in dry-cured ham.

• 한국축산식품학회지
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• 제43권1호
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• pp.25-45
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• 2023

This study evaluated the antibacterial and antioxidant activities of ethanol extract of calamansi pulp (CPE) and its effect on quality and biogenic amine (BAs) formation in pork patties during storage. The CPE were prepared in various conditions (ethanol concentrations of 50%, 70%, and 90% with extraction periods of 3 and 6 days). The extract with potent antibacterial and antioxidant activities (90%, 6 days) was selected for addition to pork patties. Three groups were tested: Control (without extract addition), CPE addition at 0.2% w/w (0.2PCPE), and 0.4% w/w (0.4PCPE). The addition of CPE inhibited the formation of BAs, mainly cadaverine, histamine, and tyramine, in pork patties during storage. The pH and bacterial count of pork patties decreased significantly in a concentration-dependent manner following the addition of CPE. The instrumental color (CIE L^*, CIE a^*, and CIE b^*) tended to be higher in 0.4PCPE than in the control during storage. The thiobarbituric acid reactive substances and volatile basic nitrogen (VBN) values of pork patties were affected by CPE, showing a reduction toward lipid oxidation at any storage period, and maintaining the lowest VBN value in 0.4PCPE at the final storage day. Similarly, the reduction of total BAs in pork patties was observed ranged between 3.4%-38.1% under treatment with 0.2% CPE, whereas 18.4%-51.4% under 0.4% CPE addition, suggesting significant effect of CPE to improve meat quality. These novel findings demonstrate the efficacy of 0.4% CPE as a natural compound to preserve the quality and reduce BAs formation in pork patties during storage.

• 한국축산식품학회지
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• 제43권5호
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• pp.840-858
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• 2023

This study was designed to compare the quality changes in mackerel fillets stored under different conditions by using hyperspectral imaging (HSI) techniques. Fillets packaged in vacuum were stored for six days under five different conditions: refrigerated at 4℃ (R group); iced at 5±3℃ (I group); kept at an ambient of 17±2℃ (A group); frozen at -18℃ for 24 h and thawed in a refrigerator at 4℃ for 5 h on the sampling day (FTR group); FTR thawed in tap water instead of thawing in a refrigerator (FTW group). The FTR group had the lowest total bacterial count, drip loss, 2-thiobarbituric acid reactive substances, volatile basic nitrogen, and texture profile analysis values among groups during the entire storage period (p<0.05). Scanning electron microscopy revealed that the FTR group had less damage, while the other groups had shrunken muscle tissues. HIS integrated with the partial least squares model yielded reliable and efficient results, with high R²_cv values, for several quality parameters of the mackerel fillets. Overall, the FTR group, involving freezing and thawing in a refrigerator, appears to be the most favorable option for maintaining the quality of mackerel fillets, which could be practically implemented in the industry. HSI is a suitable and effective technique for determining the quality of mackerel fillets stored under different conditions.

• Animal Bioscience
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• 제36권5호
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• pp.797-809
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• 2023

Objective: Many scientists have investigated solutions to reduce microbiological risks in dry-aged meat after the dry-aging technology was revived for high quality and value-added premium meat product in the market. This study aimed to investigate the effect of scoria powder in onggi (Korean earthenware) on the meat quality of pork loins during 21 days of dry aging and to elucidate its mechanism of action. Methods: The pork loins were randomly divided into three groups: aged in vacuum-packaging, onggi containing red clay only (OR), and onggi containing 30% red clay and 70% scoria powder (OS). Microbial analyses (total plate count and Lactobacillus spp.) and physicochemical analyses (pH, shear force, volatile basic nitrogen [VBN], water activity, 2-thiobarbituric acid reactive substances, water content, water holding capacity, cooking loss, and color analysis) of aged meat were conducted. Far-infrared ray emission, quantification of immobilized L. sakei and microstructure of onggi were investigated to understand the mechanism. Results: On day 21, the meat aged in OS exhibited lower pH, shear force, VBN, and water activity than those aged in OR, along with an increase in the number of Lactobacillus spp. OS had a smaller pore diameter than OR, implying lower gas permeability, which could promote the growth of L. sakei. Conclusion: OS improved the microbiological safety and storage stability of pork loin during dry aging by increasing number of Lactobacillus spp. possibly due to low permeability of OS.

• 유기물자원화
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• 제31권2호
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• pp.53-61
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• 2023

하수슬러지의 대부분은 생물학적 처리에 의한 미생물에 의해 분해 가능한 유기물질을 다량 함유하고 있는 유기성 폐기물이다. 기존의 하수슬러지 처리방법으로는 건조, 소각, 반탄화 그리고 탄화 등의 기술을 이용하여 감량화 및 연료화를 진행하고 있다. 그러나, 건조를 기반으로 하여 539kcal/kg의 잠열이 소비됨으로 에너지 소비가 높은 단점이 지적되고 있다. 따라서 본 연구에서는 열화학적 처리인 수열탄화(HTC)를 통해 고형연료를 생산하고자 한다. 고형연료의 가치를 평가하기 위하여 탄화도 및 연료비의 특성을 분석하였다. 그 결과 수열탄화 반응온도가 증가할수록 탄화도의 상승으로 저위발열량도 약 500kcal/kg 상승하였다. H/C, O/C, Ratio는 1.78, 0.46에서 1.57, 0.32로 감소하는 경향을 보였다. 건조슬러지의 가연분(고정탄소+휘발분) 대비 회분(Ash)의 비율이 0.25 이상으로 나타날 경우는 수열탄화를 진행하여도 탄화도 및 발열량의 증가되지 않는다는 것을 도출하였다.

• 한국축산식품학회지
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• 제43권6호
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• pp.1170-1182
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• 2023

The aim of this study was to determine the effect of chitosan (CH)-based nanocomposite coating applications [chitosan+TiO₂ (CHT) and chitosan+TiO₂+rosmarinic acid (CHTRA)] on changes in quality attributes of rainbow trout fillets during cold storage (4℃). Fish fillets were randomly divided into four groups and subjected to treatments (CH, CHT, CHTRA, and control). After treatments, the groups were packaged under a modified atmosphere (40% CO₂+30% O₂+30% N₂) and stored at 4℃ for 18 days. During cold storage, the samples were subjected to physico-chemical and microbiological analyses. During storage, CH, CHT, and CHTRA treatments showed lower aerobic mesophilic and psychrotrophic bacteria counts than the control. However, the differences between coating treatments were not significant. The highest mean pH value was determined in the control group. As the storage time increased, the thiobarbituric acid reactive substances value increased. At the end of the storage period, no significant differences were observed between the treatments, including in the control group. The total volatile basic nitrogen (TVB-N) level in the control group was above 25 mg/100 g on day 15 of storage. However, the TVB-N level in the treatment groups was below 20 mg/100 g on day 18. It was also determined that coating application×storage period interaction had a significant effect on all color parameters (p<0.01). At the end of storage, the highest CIE L* was observed in CHTRA treatment. However, the value of this treatment did not differ from that of the CH treatment.

• Animal Bioscience
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• 제37권1호
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• pp.123-130
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• 2024

Objective: Beef of Jeju black cattle (JBC) is considered as a healthy meat type due to its significantly higher unsaturated fatty acids (UFA). Lipid (e.g., UFA) is highly susceptible to oxidizing agents, which results in the quality deterioration and economic value loss of meat products. Therefore, development and application of novel preservative techniques is necessary to improve the shelf-life stability of high-UFA beef. The objective of this study was to assess the applicability of chitosan-based coatings in preservation of JBC beef. Methods: Different coating solutions: 2% chitosan alone, and 2% chitosan containing 0.1% or 0.3% gallic acid were prepared to investigate their applicability in preservation of fresh beef during storage. Jeju black cattle beef (2-cm thick steaks) were non-coated (control) or coated with the above coating solutions, placed on trays, over-wrapped with plastic film and stored at 4℃. The microbiological indices, color, total volatile basic nitrogen (TVBN) and lipid oxidation of the beef were investigated after 1, 10, and 21 days of storage. Results: Coating with 2% chitosan alone reduced the spoilage bacteria count, TVBN and thiobarbituric acid reactive substances levels in the beef compared with control during storage (p<0.05). Noticeably, coating with 2% chitosan containing 0.1% or 0.3% gallic acid was more effective on retardation of spoilage bacteria growth, lipid oxidation and discoloration in the beef compared to the chitosan coating alone over the storage period (21 days) (p<0.05). Conclusion: Taken together, the combined chitosan and gallic acid coating could be used as a bio-preservative technique in the meat industry.

• 한국축산식품학회지
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• 제44권1호
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• pp.189-203
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• 2024

This study investigated the antioxidant activity of radish seed oil (RSO) and its effects on the quality and storage characteristics of pork patties. To assess the antioxidant capacity of RSO, this study analyzed fatty acid composition, peroxide value (PV), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Pork patties were manufactured with the addition of RSO-0.4%, 0.8%, 1.6%, and 2.4%-and measured in terms of proximate composition, pH, water holding capacity (WHC), cooking loss (CL), color, texture profile analysis, and a sensory evaluation. Total microbial count (TMC), volatile basic nitrogen (VBN), thiobarbituric acid reactive substances (TBARS), and PV were measured at 1, 3, and 7 days of refrigerated storage. The DPPH radical scavenging activity of RSO was found to be 75.46%. In the cases of WHC and CL, there was no significant differences observed between RSO0.4%, RSO0.8%, and positive control (PC; p>0.05). Meanwhile, RSO2.4% showed significantly lower hardness, springiness, gumminess, and chewiness than PC (p<0.05), and these values tended to decrease with the addition of increasing RSO. In terms of storage characteristics, with an increase in the amount of RSO added, TMC, VBN, TBARS, and PV all decreased; among the treatment groups, RSO2.4% showed the lowest values. In conclusion, RSO exhibits antioxidant activity, but when added in large amounts, it negatively affects the quality characteristics of patties while positively impacting their storage properties, thus necessitating a balanced consideration of both outcomes. Therefore, adding 1.6% RSO is considered to be the most appropriate level for formulations to be used in practice.