• Food Science and Preservation
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• v.21 no.1
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• pp.62-68
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• 2014

This study was performed in order to investigate the functional components of 5 kinds of marine algae. We have collected 5 samples of marine algae, such as the sea mustard (Undaria pinnatifida), sea tangle (Laminaria iaponice), sea weed fusiforme (Hizikia fusiforme), green laver (Entetomotpha), laver (Phophyratenera), which have been harvested in Jeollanam-do. In order to examine the functional effects, 5 kinds of marine algae were extracted with hot water ($80^{\circ}C$, 4 hr), ethanol and methanol (R.T., 4 hr), and subcritical water extract (SWE, 3 MPa, $90^{\circ}C$, $150^{\circ}C$, $210^{\circ}C$). A higher yield of extract was obtained through SWE method (3 MPa, $210^{\circ}C$) in all of the samples obtained. The highest total sugar content was 427.4 mg/g in green laver extracted with SWE (3 MPa, $210^{\circ}C$). The content of the SWE total phenolic compounds was higher than that of the water and solvent (methanol, ethanol) extracts. The anti-oxidative activities of the extracts from 5 kinds of marine algae were examined through the DPPH radical scavenging activity test. The SWE (3 MPa, $150^{\circ}C$ and $210^{\circ}C$) of the marine algae was the highest among all of the extracts. As per the results, the SWE of the marine algae contained more functional components and it had a higher antioxidant activity than those of the other extracts. The $IC_{50}$ value of tyrosinase in seaweed fusiforme and laver were higher than those of the other samples. These results strongly support the possible use of marine algae as functional materials.

• Food Science and Preservation
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• v.21 no.4
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• pp.587-592
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• 2014

Brassica spp. vegetables have been known to have biological activities such as anti-cancer and anti-inflammatory activities. In this study, we investigated the in vitro physicochemical characteristics and antioxidant activities of commonly used Brassica spp. sprout vegetables such as kohlabi (Brassica oleracea var. gongyloides), red radish (Raphanussativus L. var. sativus), broccoli (B. oleracea var. italica), cabbage (B. rapavar. glabra Regel), rape (B. napus), radish (R. sativus), and tatsoi (B. campestris var. narinosa) sprouts. Our results showed that the vegetables with the highest total phenolics contents were the radish sprout ($24.40{\pm}1.24mg\;TAE/g$) and kohlabi sprout extracts ($23.97{\pm}0.46mg\;TAE/g$). Furthermore, the vegetable with the highest total flavonoid content was the radish sprout extract ($15.30{\pm}1.35mg\;CE/g$). However, the kohlabi sprout extract showed the highest DPPH radical scavenging value ($IC_{50}=1.95mg/mL$) and ORAC value (79.03 mM TE/g). In addition,the six kinds of Brassica spp. sprout vegetable extracts, except tatsoi, significantly inhibited the reactive oxygen species (ROS) production and showed that intracellular oxidative stress is closely related tothe accumulation of differentiated adipocytes and fat during the adipogenesis of 3T3-L1 preadipocytes. These results suggest that Brassica spp. sprout vegetables, especially kohlabi and radish sprout extracts, can be used to develop natural antioxidants.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.103-134
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• 1977

The physiological and biochemical role of potassium for upland crops according to recent research reports and the nutritional status of potassium in Korea were reviewed. Since physical and chemical characteristics of potassium ion are different from those of sodium, potassium can not completely be replaced by sodium and replacement must be limited to minimum possible functional area. Specific roles of potassium seem to keep fine structure of biological membranes such as thylacoid membrane of chloroplast in the most efficient form and to be allosteric effector and conformation controller of various enzymes principally in carbohydrate and protein metabolism. Potassium is essential to improve the efficiency of phoro- and oxidative- phosphorylation and involve deeply in all energy required metabolisms especially synthesis of organic matter and their translocation. Potassium has many important, physiological functions such as maintenance of osmotic pressure and optimum hydration of cell colloids, consequently uptake and translocation of water resulting in higher water use efficiency and of better subcellular environment for various physiological and biochemical activities. Potassium affects uptake and translocation of mineral nutrients and quality of products. potassium itself in products may become a quality criteria due to potassium essentiality for human beings. Potassium uptake is greatly decreased by low temperature and controlled by unknown feed back mechanism of potassium in plants. Thus the luxury absorption should be reconsidered. Total potassium content of upland soil in Korea is about 3% but the exchangeable one is about 0.3 me/100g soil. All upland crops require much potassium probably due to freezing and cold weather and also due to wet damage and drought caused by uneven rainfall pattern. In barley, potassium should be high at just before freezing and just after thawing and move into grain from heading for higher yield. Use efficiency of potassium was 27% for barley and 58% in old uplands, 46% in newly opened hilly lands for soybean. Soybean plant showed potassium deficiency symptom in various fields especially in newly opened hilly lands. Potassium criteria for normal growth appear 2% $K_2O$ and 1.0 K/(Ca+Mg) (content ratio) at flower bud initiation stage for soybean. Potassium requirement in plant was high in carrot, egg plant, chinese cabbage, red pepper, raddish and tomato. Potassium content in leaves was significantly correlated with yield in chinese cabbage. Sweet potato. greatly absorbed potassium subsequently affected potassium nutrition of the following crop. In the case of potassium deficiency, root showed the greatest difference in potassium content from that of normal indicating that deficiency damages root first. Potatoes and corn showed much higher potassium content in comparison with calcium and magnesium. Forage crops from ranges showed relatively high potassium content which was significantly and positively correlated with nitrogen, phosphorus and calcium content. Percentage of orchards (apple, pear, peach, grape, and orange) insufficient in potassium ranged from 16 to 25. The leaves and soils from the good apple and pear orchards showed higher potassium content than those from the poor ones. Critical ratio of $K_2O/(CaO+MgO)$ in mulberry leaves to escape from winter death of branch tip was 0.95. In the multiple croping system, exchangeable potassium in soils after one crop was affected by the previous crops and potassium uptake seemed to be related with soil organic matter providing soil moisture and aeration. Thus, the long term and quantitative investigation of various forms of potassium including total one are needed in relation to soil, weather and croping system. Potassium uptake and efficiency may be increased by topdressing, deep placement, slow-releasing or granular fertilizer application with the consideration of rainfall pattern. In all researches for nutritional explanation including potassium of crop yield reasonable and practicable nutritional indices will most easily be obtained through multifactor analysis.