• Journal of Life Science
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• v.32 no.10
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• pp.784-791
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• 2022

This study observed changes in the body composition of Protaetia brevitarsis sinulensis larvae when reared with feed that included noni and nipa palm. Compared to the control group, the death rate and product yield of the treatment group were improved after the larval fasting process. The brightness of the larval powder of the treatment group increased, but the redness decreased. The crude fat content of the treated group was slightly increased according to the assays of the general components, but the mineral content was significantly increased. The total structural amino acids of the treatment group decreased, but the total free amino acids increased. The structural amino acids generally tended to decrease in the treatment group. However, the free amino acids showed no specific differences. Among the free amino acids, tryptophan, phosphoserine, and methylhistidine were highly increased in the treatment group, whereas threonine, methionine, and asparagine showed the opposite results. Among the polyunsaturated fatty acids, eicosapentaenoic acid (C20:5n3) of omega-3 was increased in the treatment group, but the omega-6 series was decreased. Since minerals, total free amino acids, and omega-3 fatty acids in the treatment group were increased compared to the control group, we suggest that noni and nipa palm can potentially be applied to the production of functionally improved substances as additional sources of feed for Protaetia brevitarsis sinulensis larvae.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.212-223
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• 2022

For the remediation and restoration of contaminated sediment at the West Sea-Byeong dumping site, dredged materials was dumped in 2013, 2014, 2016, and 2017. The physicochemical properties and benthic fauna in surface sediments of the capping area (5 stations) and natural recovery area (2 stations) were analyzed annually from 2014 to 2020 to evaluate the capping effect of the dredged materials. The natural recovery area had a finer sediment with a mean particle size of 5.91-7.64 Φ, while the sediment in the capping area consisted of coarse-grained particles with a mean particle size of 1.47-3.01 Φ owing to the capping effect of dredged materials. Considering that the contents of organic matters (COD, TOC, and TN) and heavy metals in the capping area are approximately 50 % lower (p<0.05) than that in the natural recovery area, it is judged that there is a capping effect of dredged materials. As a result of analyzing macrobenthic assemblages, the number of species and ecological indices of the capping area were significantly lower than that of the natural recovery area (p<0.05). The number of species and ecological indices at the capping area were increased for the first four years after the capping in 2013 and 2014 and then tended to decrease thereafter. It is presumed that opportunistic species, which have rapid growth and short lifetime, appeared dominantly during the initial phase of capping, and the additory capping in 2016 and 2017 caused re-disturbance in the habitat environment. In the natural recovery and capping areas, Azti's Marine Biotic Index (AMBI) was evaluated as a fine healthy status because it maintained the level of 2^nd grades (Good), whereas Benthic Pollution Index (BPI) remained at the 1^st and 2^nd grade. Therefore, capping of dredged materials for remediation of contaminated sediment in the dumping site has the effect of reducing the pollution level. However, in terms of the benthic ecosystem, it is recommended that the recovery trend should be monitored long-term. Additionally, it is necessary to introduce an adaptive management strategy when expanding the project to remediate the contaminated sediment at the dumping area in the future.

• Journal of Wetlands Research
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• v.24 no.2
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• pp.83-92
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• 2022

The amount of the plastic waste has been increasing according to global demand for plastic. Microplastics are the most hazardous among all plastic pollutants due to their toxicity and unknown physicochemical properties. This study investigates the optimal methodology that can be applied to sewage samples for detecting microplastics before discussing reducing microplastics in MWTPs. In this study, the effect of different pretreatment methods while detecting microplastic analysis of MWTP influent samples was investigated; the samples were collected from the J sewage treatment plant. There are many pretreatment methods but two of them are widely used: Fenton digestion and hydrogen peroxide oxidation. Although there are many pretreatment methods that can be applied to investigate microplastics, the most widely used methods for sewage treatment plant samples are Fenton digestion and H₂O₂ oxidation. For each pretreatment method, there were factors that could cause an error in the measurement. To overcome this, in the case of the Fenton digestion pretreatment, it is recommended to proceed with the analysis by filtration instead of the density separation method. In the case of the H₂O₂ oxidation method, the process of washing with distilled water after the reaction is recommended. As a result of the analysis, the concentration of microplastics was measured to be 2.75ea/L for the sample using the H₂O₂ oxidation method and 3.2ea/L for the sample using the Fenton oxidation method, and most of them were present in the form of fibers. In addition, it is difficult to guarantee the reliability of measurement results from quantitative analysis performed via microscope with eyes. A calibration curve was created for prove the reliability. A total of three calibration curves were drawn, and as a result of analysis of the calibration curves, all R² values were more than 0.9. This ensures high reliability for quantitative analysis. The qualitative analysis could determine the series of microplastics flowing into the MWTP, but could not confirm the chemical composition of each microplastic. This study can be used to confirm the chemical composition of microplastics introduced into MWTP in the future research.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.99-110
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• 2022

We investigated physicochemical properties and isotopic compositions of organic matter (δ¹³C_TOC and δ ¹⁵N_TN) in the old fish farming (OFF) site after the cessation of aquaculture farming. Based on this approach, our objective is to determine the organic matter origin and their relative contributions preserved at sediments of fish farming. Temporal and spatial distribution of particulate and sinking organic matter(OFF sites: 2.0 to 3.3 mg L^-1 for particulate matter concentration, 18.8 to 246.6 g m^-2 day^-1 for sinking organic matter rate, control sites: 2.0 to 3.5 mg L^-1 for particulate matter concentration, 25.5 to 129.4 g m^-2 day^-1 for sinking organic matter rate) between both sites showed significant difference along seasonal precipitations. In contrast to variations of δ¹³C_TOC and δ¹⁵N_TN values at water columns, these isotopic compositions (OFF sites: -21.5‰ to -20.4‰ for δ¹³ C_TOC, 6.0‰ to 7.6‰ for δ¹⁵N_TN, control sites: -21.6‰ to -21.0‰ for δ¹³C_TOC, 6.6‰ to 8.0‰ for δ¹⁵N_TN) investigated at sediments have distinctive isotopic patterns(p<0.05) for seawater-derived nitrogen sources, indicating the increased input of aquaculture-derived sources (e.g., fish fecal). With respect to past fish farming activities, representative sources(e.g., fish fecal and algae) between both sites showed significant difference (p<0.05), confirming predominant contribution (55.9±4.6%) of fish fecal within OFF sites. Thus, our results may determine specific controlling factor for sustainable use of fish farming sites by estimating the discriminative contributions of organic matter between both sites.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.23-53
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• 2023

In this review paper, previous studies on layered double hydroxides (LDHs) published in the Korean Citation Index (KCI) were examined to investigate a research trend for LDHs in Korea. Since the first publication in 2002, 160 papers on LDHs have been published until January 2023. Among the 31 academic fields, top 5 fields appeared in the order of chemical engineering, chemistry, materials engineering, environmental engineering, and physics. The chemical engineering shows the highest record of published paper (71 papers) while around 10 papers have been published in the other four fields. All papers were reclassified into 15 research fields based on the industrial and academic purposes of using LDHs. The top 5 in these fields are in order of environmental purification materials, polymer catalyst materials, battery materials, pharmaceutical/medicinal materials, and basic physicochemical properties. These findings suggest that researches on the applications of LDH materials in the academic fields of chemical engineering and chemistry for the improvement of their functions such as environmental purification materials, polymer catalysts, and batteries have been being most actively conducted. The application of LDHs for cosmetic and agricultural purposes and for developing environmental sensors is still at the beginning of research. Considering a market-potential and high-efficiency-eco-friendly trend, however, it will deserve our attention as emerging application fields in the future. All reclassified papers were summarized in our tables and a supplementary file, including information on applied materials, key results, characteristics and synthesis methods of LDHs used. We expect that our findings of overall trends in LDH research in Korea can help design future researches with LDHs and suggest policies for resources and energies as well as environments efficiently.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.2
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• pp.147-157
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• 2023

Centella asiatica extract is widely used as a raw material for cosmetics due to its various effects, but it is difficult to expect penetration into the skin due to its high molecular weight and low solubility. In order to solve these problems, lipid-based liposomes of various types were developed to increase skin absorption. Therefore, in this study, we tried to increase the skin absorption rate by preparing transfersomes using surfactants as edge activators in existing liposomes. Liposome and transfersomes containing Span 80 and Tween 20, 60, 80, and 85, respectively, were prepared using a high-pressure homogenizer, and we evaluated the particle size, polydispersity index, zeta potential, and skin absorption rate. As a result, there was almost no change in the physical properties of particle size, polydispersity index and zeta potential from 25 ℃ to 60 d, and the particle size of transfersomes containing Tween 20, 60, and 80 increased after 60 d at 45 ℃. Madecassoside, main substances of the Centella asiatica extract was used as an standard and madecassoside was measured and calculated when measuring the skin absorption rate using Franz diffusion cells. As a result, formulations containing Tween 20 were the most, whereas formulations containing Span 80 were the least. According to the skin absorption coefficient (Kp) value, all formulations showed 'very fast', and the absorption rate was similar or greater than that of liposomes, except for formulations containing Span 80. Through this, it was confirmed that the larger the HLB value of the nonionic surfactant, the smaller the particle size of the transfersome, and the increased skin absorption rate due to the increased flexibility of the vesicle membrane. Through this study, transfersome using surfactant as an edge activator can be expected to solve local skin problems not only as a cosmetic raw material or product, but also by increasing skin absorption.

• Food Science and Preservation
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• v.30 no.1
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• pp.88-97
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• 2023

As livestock consumption in Korea has been gradually increasing, the quality of the final products has been improved to meet this increased demand. In particular, maintaining the water holding capacity (WHC) and minimizing the drip loss during the thawing of frozen meat are of utmost importance. This study investigated the physicochemical properties of frozen pork subjected to thawing under different conditions: at room temperature (20℃, under air), at a low temperature (4℃ refrigerator, under air), under water (20℃, under water in a vacuum bag), under microwave (microwave-thawing, 260 W), and under low-pressure tumbling (20℃, 0.015 bar, tumbling). The shortest thawing time for frozen pork was recorded upon low-pressure tumbling thus indicating a fast heat transfer. The lowest drip loss (0.2%) and highest WHC (94.5%) were also recorded under this condition. A significantly higher drip loss was observed upon microwave- (1.0%) and water-thawing (1.2%), which resulted in the lowest WHC in microwave thawing (87.2%). The highest total count of aerobic bacteria and coliform group were observed upon room temp thawing while the low pressure tumbling and thawing resulted in the lowest aerobic bacteria (1.90 log CFU/g) and coliform (0.78 log CFU/g) count. Consequently, thawing by low pressure tumbling afforded the best food quality.

• Food Science and Preservation
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• v.31 no.2
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• pp.267-275
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• 2024

Artemisia fukudo Makino belongs to the Asteraceae family, is a halophyte that can grow in salinity soils and is known for its various physiological activities. However, few studies were comparing it according to the growth environment. Therefore, in this study, we analyzed the antioxidant activity, functional ingredients, and safety of Artemisia fukudo Makino according to the growth environment. Total polyphenol content was the highest in native mature leaves, but 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity was higher in cultivated leaves than in native leaves. The total mineral content, excluding sodium, was higher in cultivated than in native leaves. The content of potassium and calcium was higher in cultivated leaves than in native leaves. In addition, heavy metal analysis showed that cultivated leaves were generally lower than those of native leaves. Residual pesticides were not detected in all samples. In conclusion, since there is no significant difference in cultivated leaves compared to native leaves, it was judged that cultivated leaves could be used as a variety to be grown and mass-produced.

• Food Science and Preservation
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• v.16 no.5
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• pp.686-698
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• 2009

We sought basic data for product development and storage improvement of abalone. We explored drying methodologies, such as shade drying, cold air drying, and vacuum freeze drying. We also examined various physicochemical features of both meat and viscera. Raw abalone meat had $78.88{\pm}1.01%$ moisture, $9.24{\pm}0.27%$ crude protein, and $10.05{\pm}0.81%$ carbohydrate (all w/w). The moisture level of dried abalone meat was highest after cold air drying, at $18.38{\pm}0.91%$, and lowest after vacuum freeze drying, at $1.05{\pm}0.05%$. The total amino acid content of raw abalone meat was $17,124.05{\pm}493.18\;mg%$, and fell after shade-drying to $12,969.92{\pm}583.65\;mg%$, and to $13,328.78{\pm}653.11\;mg%$ after cold air drying. The total free amino acid content of raw abalone meat was $4,261.99{\pm}106.55\;mg%$, and rose after shade-drying to $6,336.50{\pm}285.15\;mg%$, to $5,072.04{\pm}248.53\;mg%$ after cold air drying, and to $4,638.85{\pm}218.03\;mg%$ after vacuum freeze drying. The fatty acid proportions in raw abalone meat were $47.00{\pm}0.99%$ saturated, $22.18{\pm}1.05%$ monounsaturated, and $30.82{\pm}1.45%$ polyunsaturated. In the viscera, however, the proportions were $36.72{\pm}0.74%$ saturated, $25.44{\pm}1.12%$ monounsaturated, and $37.84{\pm}1.67%$ polyunsaturated. The contents of chondroitin sulfate in raw abalone were $11.95{\pm}0.35%$ in meat and $7.71{\pm}0.19%$ in viscera (both w/w). After shade-drying, the chondroitin sulfate content was $16.57{\pm}0.90%$ in meat and $9.24{\pm}0.50%$ in viscera. The figures after cold air drying were $16.17{\pm}0.79%$ and $12.44{\pm}0.61%$, and those after vacuum freeze drying $25.17{\pm}1.16%$ and $15.22{\pm}0.70%$ (thus including the highest meat content). The level of collagen in raw abalone was $69.80{\pm}3.07\;mg/g$ in meat and $40.62{\pm}1.79\;mg/g$ in viscera. Meat and viscera dried in the shade had $144.05{\pm}7.78\;mg/g$ and $44.16{\pm}2.39\;mg/g$ collagen, respectively, whereas the figures after cold air drying were $133.29{\pm}6.53\;mg/g$ and $69.20{\pm}3.39\;mg/g$, and after vacuum freeze drying $137.51{\pm}6.33\;mg/g$ and $60.61{\pm}2.79\;mg/g$. Volatile basic nitrogen values of raw abalone showed a higher content in viscera, at $19.01{\pm}0.84\;mg%$, compared to meat ($10.10{\pm}0.44\;mg%$). The value for shade-dried abalone meat was $136.77{\pm}7.37\;mg%$ and that of viscera $197.97{\pm}10.69\;mg%$. After cold air drying the meat and visceral values were $27.32{\pm}1.34\;mg%$ and $71.37{\pm}3.50\;mg%$, respectively.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.133-141
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• 2016

The physicochemical properties, antioxidant capacities, and sensory optimization of taro (Colocasia esculenta) under different aging conditions were investigated to develop black taro. Black taro was processed in three steps (steaming: $95{\pm}3^{\circ}C$ for 1 h; aging: 85, 90, $95^{\circ}C$ for 20, 40, and 60 h; drying: $60^{\circ}C$ for 24 h) and ground into a powder for all experiments. Black taro showed an increased crude fiber content and browning index compared to raw taro. Calcium oxalate contents, reducing sugar contents, moisture contents, and lightness values were decreased during the processing of taro. Improvements in total polyphenol content and antioxidant activity (DPPH, ABTS, FRAP) were observed in the black taro samples aged at higher temperature. Response surface methodology was used for sensory optimization, and the optimum aging conditions with the highest acceptance values were found to be $88.73^{\circ}C$ for 39.50 h for taste, and $88.82^{\circ}C$ for 42.60 h for overall acceptance.