• 한국식품영양학회:학술대회논문집
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• 한국식품영양학회 2001년도 동계 학술심포지움
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• pp.39-74
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• 2001

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s∼1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great, progress and success was obtained in development of high-quality japonica cultivars and qualify evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice caltivars and special rices adaptable for food processing such as large kernel, chalky endosperm aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and torture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak. hot paste and consistency viscosities of viscogram with year difference. The high-quality rice variety “Ilpumbyeo” showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic mcroscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high Probability of determination. The ${\alpha}$ -amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, shelved the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogiadation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice bread. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large gram rices showed better suitability for fermentation and brewing. Our breeding efforts on rice quality improvement for the future should focus on enhancement of palatability of cooked rice and marketing qualify as well as the diversification in morphological and physicochemical characteristics of rice grain for various value-added rice food processings.

• 한국물환경학회지
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• 제38권5호
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• pp.220-230
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• 2022

Seasonal variability of water quality in the upland headwater streams in ten forested catchments (37.0~209.0 ha) was examined from April to November 2021. Here, seven physicochemical parameters were analyzed including pH, electrical conductivity (EC), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (T-N), total phosphorous (T-P), and BOD/TOC. The parameters were compared with those of lowerland rivers as middle and lower reaches within a watershed. The pH showed was low (6.4~6.9) during all the seasons, however, BOD and BOD/TOC in the fall season were 2-fold higher than in the spring and summer seasons. Based on environmental standards, the water quality level revealed that the upland headwater streams maintained the purity and cleanliness of water except for pH in the summer season. BOD/TOC of all the seasons and BOD of the fall season in the upland headwater streams were higher than that in the lowerland rivers, whereas the rest of the physicochemical parameters in the upland headwater streams were lower than that in the lowerland rivers. Additionally, the water quality level maintained the purity and cleanliness of water as "Good" in two reaches. The unique aspects of our study design enabled us to draw inferences about water quality characteristics with temporal and spatial analysis in upland headwater streams. This design will be useful for the long-term strategy of effective water quality management for integrated upland headwater streams and lowerland rivers within a watershed.

• The Korean Journal of Ecology
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• 제20권1호
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• pp.61-68
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• 1997

Due to its lack of wave action and tide ecosystem in Inchon dock lacks in marine characteristics. Structural condition in the dock is artificially similar to that of lake. The purposes of this study was to clarify the water quality, to provide the basic physicochemical data and tl resolve the causation of ？미 blooming. Samples were obtained monthly from four stations in Inchon dock during January to December, 1991. Water temperature ranged from $2.7^{\circ}C$ to $27.6^{\circ}C$ under the strong influence of air temperature. Salinity varied between 24.7%-30.4% thus being influenced by freshwater discharged from a spring. Dissolved oxygen was concentrated from 0.1-13.92 mg/l and suspended solids were 6.9-231.0 mg/l. The physicochemical factors were similar to those investigated 10 years ago. However, increased concentration of nitrogenous nutrients initiated ？미 blooming and its process was accelerated to reach eutrophication. Algal blooming was proceeded in March and August.

• 한국식품영양학회지
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• 제21권4호
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• pp.499-509
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• 2008

The purpose of this study was to investigate the changes in physicochemical and sensory properties of raw fruits during washing and chlorine treatments. Strawberry and banana were pre-prepared at different concentration of chlorinated water(0 ppm, 50 ppm and 100 ppm), immersion time(3 min and 5 min), and number of post-rinsing(1 time, 2 times and 3 times). The physicochemical properties such as pH, sugar contents, residual chlorine contents, color values and hardness of the fruits were analyzed, and the sensory quality were evaluated throughout the sterilization treatment process. After washing strawberry with 100 ppm chlorinated water and 3 times of post-rinsing, pH and residual chlorine contents were showed a little difference, while sugar contents, hardness, and color values(L, a and b) were reduced. In case of banana, pH, sugar contents and residual chlorine contents were not affected, and hardness and L color value were reduced. However, a and b color values of banana were gradually increased as the development of brown discoloration. Sensory properties of the samples were affected by the chlorine sterilization treatment. In overall acceptance, strawberry and banana treated with 100 ppm chlorinated water showed the lowest scores among treatments. Therefore it could be suggested that the application of 50 ppm chlorinated water for $3{\sim}5$ minutes with over 3 times of post-rinsing was the effective pre-preparation method without affecting the quality of the fruits.

• Journal of Dairy Science and Biotechnology
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• 제19권1호
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• pp.13-21
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• 2001

Milk can be regarded as a complete food, containing protein, fat, lactose, vitamins and minerals. Milk is heated for a variety of reasons. The main reasons are: to remove pathogenic organisms; to increase shelf-life. But, when milk is heated, many changes take place: denaturation of whey proteins and interaction with casein, Maillard browning, losses of vitamin and minerals. The addition of a additive and milk powder to flavor and taste may cause undesirable change of quality during heating milk. The reconstituted milk is the milk product resulting from the addition of water to the dried or condensed form in the amount necessary to re-establish the specified water solids ratio. Therefore, according to the increasement of consumption of processed milk, the necessity for study about the quality of processed milk mixed with reconstituted milk arose.

• 한국식품저장유통학회지
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• 제4권2호
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• pp.155-162
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• 1997

This work was designed to determine the effect of steaming-Pretreatment on Physicochemical and functional properties of roasted Polygonatum odoratum roots. Steaming treatments led to some reduction in the contents of water solubles, such as total solid, reducing sugar and free-amino nitrogen of the unroasted samples. Moreover, roasting processing caused decrease in reducing sugar and free-amino acid, with increase in total soluble solid and browning color of the samples, which showed the dependence of steaming treatment as well as roasting temperature. Electron-donating ability and nitrite-scavenging ratio of the samples were also highly developed along with roasting processing at 17$0^{\circ}C$ within 35min. Considering the physicochemical and some functional parameters of water extracts of roasted samples, roasting at above 14$0^{\circ}C$ for over 55min or at 17$0^{\circ}C$ for around 35min was recommendable for the higher quality of Polygonatum odoritum tea, which conditions were similarly adapted for both steamed and unsteamed samples.

• 한국식품영양과학회지
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• 제29권1호
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• pp.15-19
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• 2000

Physicochemical properties of frozen immatured soybean (Miwon) under various thawing conditions were investigated. The moisture content, density and other chemical compositions were not affected by the thawing conditions. Thelightness of soybean and soybean hull decreased when thawing with 1$0^{\circ}C$ water while it increased when other thawing conditions used. Hardness and vitamin C content decreased with all thawing conditions ; especially decrease in vitamin C content was severe with microwave thawing. Lipoxygenase activity was significantly decreased when thawing with microwave and 1$0^{\circ}C$ water. It was recommended that thawing with 1$0^{\circ}C$ water was the most apropriate method in terms of overall quality.

• 한국환경과학회지
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• 제20권5호
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• pp.575-580
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• 2011

This study characterized water quality of groundwater and purified water used for drinking water in 30 schools in Gyeongsangbukdo Province. The results of the study showed that 43% of groundwater and 45% of purified water were not suitable for drinking. Among them, microbial contaminations were the most serious problem. In raw groundwater, the exceeding rates of total colony counts was the highest in August (53.6%). Purified water samples showed higher rate of exceeding drinking water standard for total colony counts while showing lower rate of exceeding drinking water standard for total coliforms and fecal coliforms in March and August. Overall, proper managements for microbial contaminations are required for both groundwater and purified water. Furthermore, special attention should toward students not to drink water when groundwater or purified water exceeds the drinking water quality standard.

• 한국관개배수논문집
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• 제18권1호
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• pp.25-32
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• 2011

In order to effectively manage the reservoir, reservoir water quality management should be based on physicochemical and configurational characteristics. In this research, correlation between factors affecting the reservoir water quality was examined. Chl-a and COD shows the highest positive correlation. Chl-a and T-P also has a high positive correlation, however Chl-a and T-N show lower correlation relatively. Even though T-N is an important factor for phytoplankton growth which increase Chl-a concentration, corelation of Ch1-a and T-N shows that enough nitrogen in the reservoir isn't no longer limiting factor. The age of reservoir can cause of increasing COD and SS. Embankment height and elevation of reservoirs shows strong negative correlation to water quality. That means reservoir which is higher embankment height and locate in higher elevations is less contaminated. Regression expression was derived with Chl-a and water quality parameters, and height of reservoir. Finally Chl-a was simulated using regression expression and it was a good approach to predict the Chl-a concentration.

• 한국산림과학회지
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• 제89권2호
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• pp.241-248
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• 2000

북한산국립공원(北漢山國立公園) 북동사면(北東斜面) 일대(一帶) 계류수(溪流水)의 이화학적(理化學的) 수질특성(水質特性)을 파악함으로써 국립공원내(國立公園內) 계류수질(溪流水質) 보전(保全)을 위한 과학적 기초 자료를 제공하기 위하여 1998년 7월부터 1999년 11월까지 매월 4개 지점의 계류수질을 분석한 결과, 이 지역 계류수의 평균pH는 6.65, 평균용존산소량은 $10.7mg/{\ell}$로 하천수질환경기준에 의한 상수원수 1급수의 범위 내였다. 또한, 이 지역 계류수(溪流水)는 연수(軟水)이었으며, 평균용존산소포화도(平均溶存酸素飽和度)는 96.7%로 포화상태이었다. 북한산 국립공원을 이용하는 탐방객수(探訪客數)의 증가(增加)는 계류수의 용존이온량을 증가시켜 계류수의 전기전도도(電氣傳導度)를 상승시키고 계류수질오염(溪流水質汚染)에 영향(影響)을 미치는 것으로 분석(分析)되었으며, 직선회귀분석결과(直線回歸分析結果) 1% 수준에서 유의(有意)하였다. 북한산 북동사면 일대 계류수에서 전기전도도(電氣傳導度)와 용존음이온량($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$)은 상류(上流)보다는 하류(下流)에셔 증가(增加)하였다.