• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.5
• /
• pp.666-672
• /
• 2004

Granular media filtration is used almost universally as the last particle removal process in conventional water treatment plants. Therefore, superb particle removal efficiency is needed during this process to ensure a high quality of drinking water. However, every particle can not be removed during granular media filtration. Besides the pattern of particle attachment is different depending on physicochemical aspects of particles and suspension. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5) and pH control was used to destabilize particles. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. More favorable particles, i.e., particles with smaller surface charge, were well attached to the collectors especially during the early stage of filtration. This selective attachment of the lower charged particles caused the zeta potential distribution (ZPD) of the effluent to move to a more negative range. On the other hand, the ZPD of the effluent did not keep moving from less negative to more negative during the later stages of filtration, and this result was thought to be caused by two reasons: ripening effects and the detachment of flocs.

• Journal of Korean Society on Water Environment
• /
• v.33 no.3
• /
• pp.273-281
• /
• 2017

The objective of this study is to evaluate the performance of stream purification equipment system combined MBP (Micro Bubble Process) and AGBP (Aerobic Granular Biofilm Process). Based on results, the optimal HRT (Hydraulic Retention Time) of MBP and AGBP set as 0.72 and 2.4 h, respectively. In the results of continuous operation on combined MBP and AGBP, it is possible to achieve a BOD, TSS and T-P removal efficiency of 85, 90 and 94%, respectively. It also confirmed that the water quality of the stream can be purified with increasing circulation flow through water simulation evaluation applied the QUAL-NIER model. Consequently this purification system can resolve the stream purification and dry stream problem.

• Food Science of Animal Resources
• /
• v.39 no.1
• /
• pp.139-150
• /
• 2019

This study aimed to determine the suitable point of sale and consumption of different quality grade (QG) Hanwoo short loin during aging period, based on physicochemical, sensory, and microbiological quality. Short loins obtained from the carcasses of 13 Hanwoo steers and 2 bulls with 5 different QGs (1++, 1+, 1, 2, and 3) were analyzed over 28 d. QG and aging time had significant effect on water holding capacity, color, shear force, total volatile basic nitrogen (TVBN) content, and sensory traits. Higher QG groups generally exhibited a lower shear force, nucleotide content, and water holding capacity, and higher $L^*$, $a^*$, and $b^*$ values. Acceptable tenderness (shear force <5.4 kg) in QG 1++, 1+, 1, and 2 was achieved on days 7, 14, 16, and 18, respectively, and QG 3 showed a shear force of 6.8 kg, even after 28 d. Regardless of QG, TVBN content below threshold levels (20-30 mg%) was observed throughout the 28 d aging period, while total plate counts above 7 Log CFU/g were seen at 21 d. In conclusion, it is recommended that Hanwoo beef with QG 1++, 1+, and intermediate QG (1 and 2) should be sold or consumed between 7 and 21, 14 and 21, 16 and 21 d, respectively. Beef with QG 3 should be sold or consumed within 21 d, based on microbial growth, even though it has not achieved desirable tenderness. For this reason, an additional tenderizing process is recommended before this beef is ready for consumption.

• The Korean Journal of Food And Nutrition
• /
• v.35 no.6
• /
• pp.445-452
• /
• 2022

The quality and antioxidant characteristics of apios (Apios americana Medikus) according to different harvest periods and steaming treatment were investigated. The quality and antioxidant characteristics of apios were significantly different depending on harvest periods. Total starch contents was higher in 1st harvesting period as 62.32 g/100 g than other harvesting period. The water binding capacity and water solubility index was higher in 1^st harvesting period as 228.65 and 11.29% than other harvesting period. The sucrose and total free sugar contents were 3.64~8.67 and 4.49~9.54 g/100 g, respectively. Total polyphenol and flavonoid contents of apios was the highest 2^nd and 4^th harvesting period at 4.21 mg GAE/g and 611.11 ㎍ CE/g, respectively. DPPH radical scavenging activity was higher in 1st harvesting period as 84.96 mg TE/100 g than other harvesting period, and decreased as the harvest periods were delayed. ABTS radical scavenging activity and ferric-reducing antioxidant power were 43.81~47.89 mg TE/g and 231.20~264.07 mM/100 g, and increased to 50.58~51.44 mg TE/g and 342.55~384.29 mM/100 g after heat treatment. As a result, it is thought that studies on change of quality and physicochemical characteristics according to cultivation characteristics should be preceded for cultivation stability of apios.

• Korean Journal of Agricultural Science
• /
• v.39 no.4
• /
• pp.569-575
• /
• 2012

This study was performed to investigate the effect of a sequencial washing of organic acid and distilled water on meat quality and the population of Escherichia coli of pork loin during cold storage. E. coli ATCC25922 was inoculated on the surface of sliced pork loin and 50 mL of 1% or 2% of organic acid and the same amount of distilled water was sprayed on the surface of pork loin. Then, physicochemical and microbial properties of pork loin were analyzed during cold storage. During storage period, lightness, yellowness and lipid oxidation (thiobarbituric acid reactive substances value) was higher than those of not treated control. However, the population of E. coli was decreased significantly in formic acid and distilled water sprayed pork loin samples. From these results, it can be considered that application of combination of washing of formic acid and water in the washing step of pig slaughter may be helpful to control the proliferation of E. coli.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.325-325
• /
• 2020

Low impact development (LID) is a widely used technology that aims to reduce the peak flow volume and amount of pollutants in stormwater runoff while introducing physicochemical, biological or a combination of both mechanisms in order to improve water quality. This research aimed to determine the effect of hydrologic factors in removing the pollutants on stormwater runoff by an LID facility. Monitored storm events from 2010-2018 were analysed to evaluate the hydraulic and hydrological performance of a small constructed wetland (SCW). Standard methods for the examination water and wastewater were employed to assess the water quality of the collected samples (APHA et al, 1992). Primary hydrologic data were obtained from the Korea Meteorological Administration. The recorded average rainfall intensity and antecedent dry days (ADD) of SCW were 5.26 mm/hr and 7 days respectively. During the highest rainfall event (27 mm/hr), the removal efficiency of SCW for all the pollutants was ranging from 67% to 91%. While on the lowest rainfall event (0.7 mm/hr), the removal efficiency was ranging from -36% to 62%. Rainfall intensity has a significant effect to the removal efficiencies of each facility due to its dilution factor. In addition to that, there was no significant correlation of ADD to the mean concentrations of pollutants. Generally, stormwater runoff contains significant amount of pollutants that can cause harmful effects to the environment if not treated. Also, the component of this LID facility such as pre-treatment zone, media filters and vegetation contributed to the effectivity of the LID facilities in reducing the amounts of pollutants present in stormwater runof.

• The Korean Journal of Food And Nutrition
• /
• v.19 no.4
• /
• pp.532-538
• /
• 2006

Physicochemical and sensory characteristics of the jelly prepared with various levels of resistant starch were investigated in this study. Water content of RS10 sample group had significantly the highest value of 12.55% and that of the RS20 sample group had significantly the lowest value of all (p<0.05). RS20 sample group had significantly the highest value in sweetness. The value of pH were decreased with increased levels of the resistant starch in jelly preparation. The Hunter L values were not significantly different among the sample groups, but the RS20 sample group had the highest value of all. The hardness was increased as the addition levels of the resistant starch was increased. Results of sensory characteristics of RS20 sample group showed significantly the higher values in strawberry aroma, sweetness and after taste and significantly the lower value in stickiness than those in the other sample groups at p<0.05. Strawberry flavor, springiness and glossiness of RS5 sample group had significantly the largest values of all (p<0.05). The sensory properties of clarity and glossiness were negatively correlated with the mechanical properties of the color value and hardness at p<0.05. Sensory sweetness and after taste showed negative correlation with the values of pH in jelly preparation(p<0.05).

• Food Science and Biotechnology
• /
• v.14 no.5
• /
• pp.676-680
• /
• 2005

This study investigated the effect of thawing rate on the physicochemical properties of frozen ostrich meat. Five different thawing rates (0.33, 0.54, 0.61, 0.68, and 0.78 cm/h) were delivered by controlling the air velocity as heat convection at $15^{\circ}C$. The pH value decreased with increasing thawing rate (p<0.05). In color measurement, $L^*$-values of all treatments were lower and $b^*$-values higher than those of control, but $a^*$-values were not significantly different among the treatments except at the thawing rate of 0.33 cm/h. Increasing thawing rate tended to improve the water holding capacity (WHC) of the samples. Thawing loss decreased with increasing thawing rate and significantly higher cooking loss was observed at the thawing rate of 0.33 cm/h. Thiobarbituric acid reactive substance (TBARS) levels of all treatments were significantly higher than that of control (p<0.05). Increasing thawing rate tended to decrease the total volatile basic nitrogen (TVBN) value. These results indicated that a rapid thawing process at $15^{\circ}C$ improved the quality of frozen ostrich meat.

• Korean Journal of Food Science and Technology
• /
• v.33 no.3
• /
• pp.353-360
• /
• 2001

Physicochemical characteristics of kochujang prepared with addition of garlic and onion, were investigated for 22 weeks of fermentation to obtain information on improving the quality of traditional kochujang. Moisture contents of kochujang increased during fermentation, but total nitrogen contents decreased slightly. The pH and titratable acidity of kochujang changed a little by addition of garlic or onion. Total sugar contents of kochujang decreased rapidly after 4 weeks, but reducing sugar contents increased until 2 weeks of fermentation. As the ratio of garlic increased, reducing sugar contents decreased. Ethanol contents increased during fermentation as mixing ratio of onion increased. Amino nitrogen contents of kochujang increased as mixing ratio of garlic or onion increased, but ammonia nitrogen contents decreased. Water activities of kochujang decreased slightly during fermentation, but consistency increased until 18 weeks. The color values of garlic or onion added kochujang were low in the L-values, but a- and b-values increased. Results of sensory evaluation showed garlic added$(2{\sim}4%)$ kochujang were more acceptable than onion added kochujang due to more favorable taste and flavor.

• Culinary science and hospitality research
• /
• v.15 no.1
• /
• pp.59-66
• /
• 2009

To investigate the physicochemical characteristics of garlic(Allium sativum L.), general composition, mineral, vitamin C, free sugar and total acidity were determined in nine sample groups from Daejeong Jeju(DJ; Alttre, Gasiorum, Seoyukgaeri), four from Korea domestics(KD; Danyang, Uiseong, Taean and Namhae), and one from China. The average composition of the group from DJ included 63.0% of water, 35.6% of organic matter, and 1.40% of inorganic matter, which were similar to that of the group from KD. The contents of magnesium, phosphorus and sodium in the group from DJ were higher than those of the group from KD, whereas the contents of iron and calcium and total acidity showed a similar level. The mean vitamin C concentration in the group from DJ, especially from Alttre, was much higher than that in the groups from KD and China. It was also observed that the free sugar content of the group from DJ(Alttre) was the highest of all other garlic groups except that from China. In conclusion, the nutrient profiles of garlic groups from Daejeong Jeju are so comparable to those from Korean domestics, and so Daejeong Jeju should be recommended as the garlic cultivation area with acceptable quality.