• Horticultural Science & Technology
• /
• v.32 no.5
• /
• pp.645-654
• /
• 2014

This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP, $1.0{\mu}L{\cdot}L^{-1}$), a known ethylene action inhibitor, on fruit quality and incidence of physiological disorders during a simulated marketing period at $25^{\circ}C$ for 20 days in early-season Asian pear (Pyrus pyrifolia Nakai) 'Hanareum' that had been treated with 0, 0.5, 1.2 or 2.4% $GA_{4+7}$. Weight loss of stored fruits increased with $GA_{4+7}$ concentration, and the 1-MCP treatment slightly reduced the weight loss rates during the marketing period. Flesh firmness decreased abruptly in all 1-MCP-untreated fruits as the storage period extended to 10 d, whereas the firmness of 1-MCP-treated fruits remained high (> 30 N) during 15 days shelf-life. The effect of 1-MCP was significantly reduced when fruits were subjected to increased GA concentration. Higher soluble solids content and acidity during extended shelf-life were also apparent in 1-MCP-treated 'Hanareum' pears. The L-values (lightness) and hue angles of 1-MCP treated samples were higher than those of controls during 20 days shelf-life, but the a-value (redness) was lower in 1-MCP treated fruits. 1-MCP treatment did not decrease the level of ethylene evolution regardless of $GA_{4+7}$ concentration during shelf-life in early-season Asian pear 'Hanareum'. By contrast, 1-MCP treatment decreased the respiration rate significantly during shelf-life. The efficacy of 1-MCP was greatest in the GA-untreated fruit and was reduced as the $GA_{4+7}$ concentration increased. 1-MCP treatment influenced the severity of physiological disorders including core browning and mealiness: 1-MCP treatment completely blocked the incidence of core browning of during 15 days shelf-life, and reduced the severity of mealiness during 20 days shelf-life regardless of $GA_{4+7}$ concentration. Based on our results, we conclude that the use of $1{\mu}L{\cdot}L^{-1}$ 1-MCP can be of great benefit for maintaining quality and preventing physiological disorders in early-season pear cultivar 'Hanareum' pear, whereas its efficacy decreases with the concentration of $GA_{4+7}$ whereas its efficacy gradually decreases when the concentration of $GA_{4+7}$ paste increased.

• Horticultural Science & Technology
• /
• v.32 no.5
• /
• pp.577-583
• /
• 2014

Benzyladenine (BA, 99% purity), MaxCel$^{(R)}$ (1.9% BA), Fruitone (3.5% NAA), MaxCel$^{(R)}$ + Fruitone, a nd s imazine were applied postbloom as fruitlet thinning agents to mature 'Hongro' and 'Fuji' apple (Malus domestica Borkh.) trees. BA and MaxCel$^{(R)}$ were applied at $100mg{\cdot}L^{-1}$ a.i. while Fruitone at $0.1mg{\cdot}L^{-1}$ a.i. and simazine at $400mg{\cdot}L^{-1}$ a.i. All PGRs were applied at 8 days after full bloom (DAFB, 6 mm fruit diameter) in both cultivars, while simazine was treated twice at 7 and 14 DAFB. In 'Hongro', the number of total fruit set per flower cluster in terminal buds was 1.67, 1.84, and 1.81 in MaxCel$^{(R)}$ + F ruitone, MaxCel$^{(R)}$, and simazine applications, respectively, when compared with 2.35 of water control. These reductions in fruit set were mainly attributed to the increased ratio of defruited clusters by the thinning agents. In 'Fuji' apple, the number of total fruit set per flower cluster in terminal buds was 1.29, 1.60, and 1.76 in MaxCel$^{(R)}$ + Fruitone, Fruitone, and MaxCel$^{(R)}$, respectively, when compared with 2.56 of water control in 'Fuji' apple. The addition of Fruitone to the MaxCel$^{(R)}$ promoted the thinning efficacy in both cultivars, compared to MaxCel$^{(R)}$ only. The thinning efficacies were similarly observed with lateral flowers in both cultivars. A significant increase of fruit weight by the postbloom thinning treatments was observed only in the BA application in 'Hongro', while the effect was observed in BA and MaxCel$^{(R)}$ in 'Fuji'. While the soluble solids content increased in the BA, MaxCel$^{(R)}$ and MaxCel$^{(R)}$+Fruitone treatments in both cultivars, other fruit quality attributes were not affected by the application of post-bloom thinning agents.

• Korean Journal of Ecology and Environment
• /
• v.35 no.2 s.98
• /
• pp.92-102
• /
• 2002

This study was conducted to compare filtering abilities of three species of freshwater mussels (Cobicula fluminea, Corbicula leana and Unio douglasiae) and to evaluate their filter feeding effects on water quality change in experimental enclosure systems. Mussel feeding in both laboratory and enclosure resulted in decrease of particulate material, such as chlorophyll, total P, SS. In the treatment with 600 individuals of mussels, chllorophyll concentration and net primary productivity decreased from $87.3{\pm}4.5\;{\mu}g/L$ and $106.3{\pm}8.8\;{\mu}gC\;L^{-1}\;hr^{-1}$ to nearly the same level as the mussel-free enclosure ($25.0{\pm}0.5\;{\mu}g/L$ and $15.6{\pm}13.3\;{\mu}gC\;L^{-1}\;hr^{-1}$, respectively)(P< 0.05, n = 6, ANOVA). In concert with the decrease of chlorophyll concentration, not only was the transparency enhanced from 0.48 m to 1.2m but also the suspended solids and total phosphorus decreased from $22.0{\pm}1.0\;mg/L$ to $7.5{\pm}0.5\;mg/L$ and $133{\pm}0.8\;{\mu}g/L$ to $70{\pm}0.0\;{\mu}g/L$, respectively (P<0.001, $r^2$>0.71, n = 11). Although slight decrease of SRP concentration and the increase of inorganic nitrogen ($NH_3-N$ and $NO_2-N$) were observed in the mussel addition enclosure, there was no statistical difference between two enclosures. Based on the filtering rate on phytoplankton and nutrient release rate in forms of feces and pseudofeces, Corbicula leana appeared to be the most efficient filter-feeder among three mussel species. These results inidicate that Cobicula play an important role in controlling particulate sestons and thus it could be applied as a biocontroler for the water quality management in lakes and reservoirs with algal blooms.

• Korean Journal of Ecology and Environment
• /
• v.39 no.2 s.116
• /
• pp.167-177
• /
• 2006

Both fish community and water quality in Lake Doam were investigated from September 2004 to August 2005. The turbidity of Lake Doam located in the upper region of the Songchun River in the South River system, Korea was high whole year due to the effects of distributed non point source pollutions in the watersheds. During the experimental periods, mean concentration of chlorophyll-a in epilimnetic layer (0 ${\sim}$ 5 m) was 18.5 ${\mu}g\;L^{-1}$ and transparency ranged from 0.3 m to 2.4 m. Average TP and TN concentrations were 111 ${\mu}g\;L^{-1}$ and 4.1 $mg\;L^{-1}$, respectively. Lake was classified as eutrophic state based on the nutrient concentrations suggested by U.S.EPA (1976). Total number of fish collected in Lake Doam was 9,600 individuals in 26 species of 6 family. Both dominant and subdominant species in the lake were P. herzi (34.9%) and Z. platypus (22.5%), respectively. Occurrence of water column species was high at upper region of the lake, whereas benthic type of species highly ,appeared in downstream area. The different fish assemblage between upper and lower area would be considered as the difference of bottom substrate and concentrations of suspended solids. In addition high appearance of Comat type of fish that is hybrid between gold fish (C, auratus) and C. auratus was found in the lake. It was unclear the reasons that high proportion of mutant species appeared in the lake. More researches are required in this area in future.

• Korean Journal of Ecology and Environment
• /
• v.44 no.2
• /
• pp.239-251
• /
• 2011

To compare the different water environments in the Jigsaw stream (st. 1, 2) and Jujin stream (st. 3, 4) crossing over the Byeonsan-Bando and Seonunsan parklands, the physico-chemical factors and the species compositions of epilithic diatoms were analyzed from March 2009 to February 2010. The mean values of conductivity (681.1 ${\mu}S\;cm^{-1}$), suspended solids (27.83 mg $L^{-1}$), biological oxygen demand (3.15 mg $L^{-1}$), total nitrogen (3.24 mg $L^{-1}$), total phosphorus (0.24 mg $L^{-1}$) and chlorophyll-${\alpha}$ (12.99 mg $m^{-3}$ ) in Jujin stream were significantly higher than each element in Jigsaw stream. Eighty taxa were classified into 73 species and seven varieties belonging to 24 genera, eight families, three suborders and two orders in Jigsaw stream. Eighty eight taxa were classified into 81 species and seven varieties belonging to 22 genera, seven families, three suborders and two orders in Jujin stream. Biological water quality assessments revealed that Jigsaw stream was ${\beta}$~${\alpha}$-oligosaprobic and Jujin stream was ${\beta}$-mesosaprobic. Dominant and diversity indices were indicated from 0.25~0.81 and from 1.73~4.14 in Jigsaw stream, respectively, and from 0.29~0.64 and from 2.72~4.02 in Jujin stream, respectively. Jujin stream was more eutrophic than those of Jigsaw stream. The different water environments between the two streams could be due to the different ecosystems of the neighboring basins of each stream crossing over in the mountain. Further studies should investigate the water environments of two streams by continuous and regular monitoring to analyze the different ecosystem mechanisms.

• Korean Journal of Ecology and Environment
• /
• v.43 no.2
• /
• pp.319-337
• /
• 2010

Major objective of this study was to determine interannual and seasonal water quality along with characteristics of longitudinal gradients along the reservoir axis of the riverine zone (Rz)-to-lacustrine zone (Lz). Water quality dataset of five years during 2003~2007 used here were obtained from Ministry of Environment, Korea and ten physical, chemical and biological parameters were analyzed in the study. Similarity analysis, based on moropho-hydrological variables of reservoir surface area, watershed area, total inflow, and outflow, showed that the reservoirs were categorized as three groups of large-dam reservoirs (Chungju Reservoir, Daecheong Reservoir and Soyang Reservoir), mid-size reservoirs (Andong Reservoir, Yongdam Reservoir, Juam Reservoir and Hapcheon Reservoir), and small-size reservoirs (Hoengseong Reservoir and Buan Reservoir). According to the data comparison of high-flow year (2003) vs. lowflow year (2005), dissolved oxygen (DO), pH, biological oxygen demand (BOD), suspended solids (SS), total nitrogen (TN), total phosphorus (TP), chlorophyll-a (CHL) and electrical conductivity (EC) declined along the longitudinal axis of Rz to Lz and water transparency, based on Secchi depth (SD), increased along the axis. These results indicate that transparency was a function of Values of pH, DO, SS, SD, and EC at each site were greater in the low-flow year (2005) than the high-flow year (2003), whereas values of BOD, COD, TN, TP and CHL were greater in the high-flow year (2003). When values of TN, TP, CHL and SD in nine reservoirs were compared in the three zones of Rz, Tz, and Lz, values of TN, TP and CHL declined along longitudinal gradients and SD showed the opposite due to the sedimentation processes from the water column. Values of TN were not statistically correlated with TP values. The empirical linear models of TP-CHL and CHL-SD showed significant (p<0.05, $R^2$>0.04). In the mid-size reservoirs, the variation of CHL was explained ($R^2$=0.2401, p<0.0001, n=239) by the variation of TP. The affinities in the correlation analysis of mid-size reservoirs were greater in the CHL-SD model than any other empirical models, and the CHL-SD model had an inverse relations. In the meantime, water quality variations was evidently greater in Daecheong Reservoir than two reservoirs of Andong Reservoir and Hoengseong Reservoir as a result of large differences of water quality by long distance among Rz, Tz and Lz.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.7
• /
• pp.821-828
• /
• 2016

The water quality and phytoplankton presence in the ballast water (BW) of 37 vessels originating from the international ports of China were investigated to facilitate negotiations for exemptions to the Ballast Water Management Convention (BWM Convention). The shortest duration given BW spent in a vessel was $3.91{\pm}4.61days$ in area "A", which included the Bohai Sea. Total suspended solids, dissolved organic carbon, and particulate organic carbon ranged from 1.80 to $266mg\;L^{-1}$, from 1.09 to $5.79mg\;L^{-1}$, and from 0.17 to $3.65mg\;L^{-1}$, respectively. A low average concentration of nutrients was measured in BW from area "C", but the concentration of nutrients in BW from area "B" (around the Changjiang estuary) was high, which may be related to the relevant supply of freshwater. A high chlorophyll-a concentration (> $1{\mu}g\;L^{-1}$) was measured in six vessels, three of which carried BW in the area "A". High abundance of phytoplankton (> $10,000cells\;L^{-1}$) was measured in four vessels, two of which carried BW in the area "C". Vessel No. 37, originating from Hong Kong Bay in area "C", showed a high density of dinoflagellates. The results suggest that BWM Convention exemption negotiations with China should be performed cautiously.

• Food Science and Preservation
• /
• v.24 no.7
• /
• pp.898-907
• /
• 2017

This study was aimed to test harvest time effect with polyethylene (PE) film liner, 1-methylcyclopropene (1-MCP) and aminoethoxyvinylglycine (AVG) treatments on fruit quality attributes in 'Sangjudungsi' persimmon fruit during cold storage. The fruits were harvested 10 days earlier in 2016 than the mature harvest time in 2015. The ethylene production was significantly lower in early harvested fruits than in mature harvested ones. Flesh firmness was maintained higher in 1-MCP treated fruit than in other treatments during cold storage. The rate of fruit weight loss was significantly inhibited by PE film liner treatment during storage, regardless of harvest time. 1-MCP treatment showed less change in fruit peel color variables ($L^*$ and $b^*$) from the calyx-end and equatorial regions during cold storage, compared with those from the control and PE film treatments. The incidence rate of fruit decay and softening was higher in PE film treated fruits than in the other treatments. However, there was no decay detected in AVG treated fruit. The early harvested fruits were maintained higher flesh firmness, compared with mature harvested fruits. Nevertheless, the mature harvested fruits showed much higher soluble solids content, the redness (Hunter a value) of the fruit peel and respiration rate, compared with early harvested fruits. Furthermore, the rate of weight loss in the fruit was remarkably inhibited in the PE film treatment.

• Food Science and Preservation
• /
• v.24 no.2
• /
• pp.215-220
• /
• 2017

Cut Kimchi cabbages ($3{\times}3cm$) were dipped in the egg shell solution (0.5% egg shell calcium/0.5% citric acid solution) and stored in the low-density polyethylene (LDPE) film bag at $4^{\circ}C$ for 2 weeks. Using this cut Kimchi cabbage, kimchi was prepared and their physicochemical qualities were investigated. Moreover, their sensory qualities were compared with Kimchi prepared with normal Kimchi cabbages. Egg shell calcium pretreatment (ET) showed the lower weight loss of cabbages than non-treatment (NT), and soluble solid compounds were decreased in all samples. Titratable acidity showed no statistical difference. After making a kimchi using cut Kimchi cabbages stored for 2 weeks no statistical differences in soluble solids and titratable acidities of kimchi stored for 7 days were shown. As a result of sensory test, preference of color was decreased and salted condition of control was the most significantly decreased. Pickled seafood odor of kimchi showed statistical difference, compared with the control. Crispness decreased in all samples. On the other hand, salty flavor and pickled seafood flavor were increased, fresh cabbage flavor, bitter flavor and carbonic flavor were decreased. Overall sensory quality of cut Kimchi cabbage (ETK) didn't show significant difference compare with kimchi prepared with normal cabbage (CON). It is possible to make kimchi with approvable sensory quality using cut Kimchi cabbage treated with egg shell calcium.

• Korean Journal of Agricultural Science
• /
• v.7 no.2
• /
• pp.190-201
• /
• 1980

This experiment was designed to optimize the process of manufacturing the soybean cheeses and to elucidate the chemical changes during ripening when the chemical changes during ripening when the milk components and enzyme preparations were added to the raw materials. Conditions for extracting soybean protein such as temperature, duration and amount of water added were determined; various coagulaters were compared by checking the curd texture and yield; starters from S. thermophilus, S. lactis MLB and S. cremoris EB-9 were tested as single- or multi-stain combinations; and the effects of skim milk and/or rennins-both microbial and calf origin-addition upon the process of manufacturing and ripening were studied. The results obtained were as follows. 1. optimal conditions for soybean extraction were found to be: temperature $100^{\circ}C$, duration 10 minutes, and amount of water added 9-fold, as considered the extraction rate of solids and proteins, and curd yield. 2. Sodium gluconate was the most effective among the coagulators tested, and 5% of single-strain starter from S. thermophilus was appered to be adequate inoculum for curd formation. 3. The effects of skim milk and/or rennins addition on the process of manufacturing and ripening of soybean cheeses were: 1) The addition of rennins resulted in fast formation of curd, especially with skim milk it was so. And Hansen rennet extracts brought better results in curd formation than Meito rennet extracts did. 2) No significant effect was observed on the changes in moisture content during ripening, however the levels of moisture contents in the products were higher in case of using Meito rennet extracts. 3) Effect on pH changes during ripening was also not significant in general, while levels of pH were decrease markedly during manufacturing and the initial stage of ripening. 4) The levels of bacterial counts were much higher in case of skim milk addition throughtout the ripening period. In general the numbers were reached to approximately $10^8cells/g$ during manufacturing, then decreased gradually to below $10^2cells/g$ in 8 weeks of ripening. 5) The addition of skim milk and/or rennin resulted in higher ripening index, and skim milk plus Meito rennet extracts was appeared to be best combination for the ripening index.