• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.465-474
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• 1999

RNase activity of Saccharomyces cerevisiae ATCC 7754 was investigated to obtain strains with high ribonucleic acid (RNA) content. The yeast strain contained two RNase activities; an acidic RNase with a optima of pH $3{\sim}4$ and an alkaline RNase with a optima pH 9. The acidic RNase activity was inhibited by $0.08\;M\;HgCl_{2}$ most drastically. The alkaline RNase activity was inhibited by 2.0 M NaCl or KCl, while enhanced by addition of $0.05\;M\;CaCl_{2},\;0.02\;M\;ZnSO_{4},\;or\;0.008\;M\;HgCl_{2}$. Various mutants of Saccharomyces cerevisiae ATCC 7754 were isolated by ethylmethane sulfonate (EMS) treatment or $\gamma$-ray/ultra violet irradiation. Among the mutants that were sensitive to high concentration of KCl which inhibits alkaline RNase, B24 was selected for high RNA content per culture volume. Growth characteristics of the mutant were comparable to those of the mother strain with optimum growth at pH $4.5{\sim}5.5$. The mutant accumulated higher content of RNA than the mother strain when glucose was used as the carbon source. However, both growth rate and total RNA content of the mutant were higher in molasses medium than in glucose medium. RNA content of the mutant increased rapidly during the early stage of growth, and then decreased gradually until the culture reached stationary phase by a fed-batch culture in a 5 L jar fermenter. Maximal cell harvest and the final RNA content using the mutant B24 were 69.6 g/L culture broth and 19.8 g/100 g of the dry cell while those using the mother strain were 68 g/L culture broth and 16.1 g/100 g of dry cell, respectively.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.378-384
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• 1999

Protopectinase (PPases) are heterologous group of enzymes that degrade pectin from the insoluble protopection which is constituent of the middle lamella and primary cell wall of higher plants by restricted depolymerization. From the previous report[6], enzymatically separated plant cells, which are produced from plant tissues by PPases treatment, showed well-conserved cellular components with their rigid cell wall and this characteristic is applicable to preparation of novel food material. The purpose of this study is to investigate the effect of medium composition of PPase production from Bacillus subtilis EK11 which was selected as a PPase producer. Various carbon sources and concentrations on PPase production were studied and corn starch at 0.7% was the most effective for production of PPase. Among the nitrogen sources, yeast extract was the most effective for PPase production and the effect of (NH4)2SO4 was notable as inotganic nitrogen source. Inorganic compounds such as KH2PO4, K2HPO4, Na3-citrate.2H2O and MgSO4 were optimized for PPase production. PPase activity was inhibited by the adition of Ba2+ or Zn2+. The optimal medium for PPase production was devised: 0.7% corn starch, 0.3% yeast extract, 1.4% KH2PO4, 0.6% K2HPO4, 0.1% Na3-citrate.2H2O and 0.02% MgSO4. PPase production by using the optimum medium was carried out with shaking cultivation at 37$^{\circ}C$. The maximum PPase activity of 256unit/ml could be obtained after the cultivation for 48hrs. The activity was increased about 2.2timesthan the activity, 112 unit/ml, in basal medium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1631-1634
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• 2011

This study was conducted to estimate the general components, minerals, and dietary fiber contents of Synurus deltoides. S. deltoides contained 81.1% moisture content, and the proportions of crude fat, crude protein, crude ash, and crude fiber were 0.3%, 4.2%, 2.6%, and 3.5%, respectively. Potassium (3,249.1 mg) was the most abundant component among the minerals in S. deltoides. In addition, S. deltoides contained many other minerals, e.g. calcium (854.8 mg), phosphorus (60.3 mg), magnesium (344.7 mg), sodium (57.3 mg), zinc (1.7 mg), iron (30.9 mg), copper (0.8 mg), and manganese (5.8 mg). Almost all of the mineral contents of S. deltoides were higher than those of Aster scaber and Ligularia fischeri, except for zinc, copper, and manganese. Total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) contents of S. deltoides were 42.6 g, 37.9 g, and 4.7 g, respectively, and these were also higher than those of A. scaber and L. fischeri used in this study. These results suggest that S. deltoides may be a valuable nutrient source.

• Microbiology and Biotechnology Letters
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• v.15 no.2
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• pp.135-139
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• 1987

Aspergillus sp. MK-24 was cultured at 3$0^{\circ}C$ in the medium consisting of 2% glucose, 0.2% NaNO$_3$, 0.02% $K_2$HPO$_4$, 0.02% MgSO$_4$ 7$H_2O$, 0.02% KCl, and at initial pH of 5.0. The production of the inhibitor on venom proteinase reached to the maximum in 7 days. Sodium nitrate or potassium nitrate as a nitrogen source was favorable. The production of inhibitor was not affected by the addition of most of the inorganic salt used but depressed by lead, zinc, cobalt, mercuric or silver salts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1757-1763
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• 2011

The physico-chemical properties of broccoli sprouts cultivated in a plant factory system with different lighting conditions were investigated. We reported that there were significant differences among the chemical and nutritional properties of the broccoli sprouts grown under different light sources. Two kinds of sugars (glucose and fructose) were detected in the plants. The amount of glucose was 2.94~3.12% and that of fructose was 1.54~2.04%. Total chlorophyll was $1,157{\pm}0.004$ mg% and chlorophyll-a $777{\pm}0.01$ mg%. All over the test materials, 2 kinds of organic acids (citric acid and malic acid) were detected. The level of citric acid was 908~1,136 mg% and its highest level was under the (Blue LED) light source. The level of malic acid was 514~834 mg% and its highest level was under the (Red LED) light source. Seven different minerals were also analyzed. The amount of K was 518 mg% and its amount was significantly higher than that of Mg or Na. There were also negligible amounts of Zn, Fe and Cu. The amounts of vitamin A, C and E under the Red LED were, $860.62{\pm}0.02\;{\mu}gRE$, $134.570{\pm}0.14$ mg% and $1.44{\pm}0.1$ IU. The amounts under the Blue LED were, $432.48{\pm}0.05\;{\mu}gRE$, $137.05{\pm}0.1$ mg% and $1.11{\pm}0.12$ IU. The amounts under both Red and Blue LEDs were, $667.33{\pm}0.11\;{\mu}gRE$, $118.50{\pm}0.09$ mg% and $1.47{\pm}0.1$ IU. And finally, the amounts under a White LED were, $640.25{\pm}0.08\;{\mu}gRE$, $119.87{\pm}0.07$ mg% and $1.31{\pm}0.15$ IU. In this study, significant changes were shown in the chemical and nutritional properties of the broccoli sprouts. These findings indicate that LED light sources stimulated germination of the plants.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.227-234
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• 2013

The purpose of this study was to determine the possibility of using Oenanthe javanica as a natural health food source. To accomplish this, its general and biological activities were measured. Its carbohydrate, crude protein, crude lipid, and ash contents were 44.7, 9.8, 8.9, and 27.8%, respectively. The K content was largest for minerals followed by Ca, P, and Mg, which means that Oenanthe javanica is an alkali material. The concentrations of total phenol and flavonoids of OJE were $88.9{\pm}0.46$ mg GAE/g, and $28.6{\pm}0.64$ mg QE/g, respectively. Gallic acid, catechin, chlorogenic acid, and caffeic acid in OJE as measured by using HPLC were $0.9{\pm}0.23$, $1.2{\pm}0.19$, $227.1{\pm}0.62$, and $4.0{\pm}0.35$ mg/g. The DPPH and ABTS radical scavenging activities of OJE were 72.2%, and 66.1%, respectively, at $1,000{\mu}g/mL$. The FRAP and reducing power of OJE were 0.79, and 0.41 absorbance units value respectively, at $1,000{\mu}g/mL$. OJE possessed significant antioxidant properties, which suggests its great potential as a functional ingredient for food applications.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.195-205
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• 1985

As a part of investigation to use the Anatrctic krill, Euphausia superba, more effectively as a food source, processing conditions, utilizations and storage stability of krill paste (intermediate product of krill) were examined and also chemical compositions of krill paste were analyzed. Frozen raw krill was chopped, agitated with $25\%$ of water to the minced krill and then centrifuged to separate the liquid fraction from the residue. This liquid fraction was heated at $98^{\circ}C$ for 20 min. to coagulate the proteins of krill, and it was filtered to separate the protein fraction. Krill paste was prepared with grinding the protein fraction, adding $0.2\%$ of polyphosphate and $0.3\%$ of sodium erythorbate to the krill paste for enhancing of functional properties and quality stability. The krill paste was packed in a carton box, and then stored at $-30^{\circ}C$. Chemical compositions of krill paste were as follows : moisture $78\%$, crude protein $12.9\%$, crude lipid $5.9\%$, and the contents of hazardous elements of krill paste as Hg 0.001 ppm, Cd 1.15 ppm, Zn 9.1 ppm, Pb 0.63 ppm and Cu 11.38ppm were safe for food. The amino acid compositions of krill paste showed relatively high amount of taurine, glutamic acid, aspartic acid, leucine, lysine and arginine, which occupied $55\%$ of total amino acid and also taurine, lysine, glycine, arginine and proline were occupied $65\%$ of total free amino acid. Fatty acid compositions of krill paste consist of $32.4\%$ of saturated fatty acid, $29.6\%$ of monoenoic acid and $38.0\%$ of polyenoic acid, and major fatty acids of product were eicosapentaenoic acid ($17.8\%$), oleic acid ($16.9\%$), palmitic acid ($15.3\%$), myristic acid ($8.7\%$) and docosahexaenoic acid ($8.4\%$). In case of procssing of fish sausage as one of experiment for krill paste use, Alaska pollack fish meat paste could be substituted with the krill paste up to $30\%$ without any significant defect in taste and texture of fish sausage, and the color of fish sausage could be maintained by the color of krill paste. Judging from the results of chemical and microbial experiments during frozen storage, the quality of krill paste could be preserved in good condition for 100 days at $-39^{\circ}C$.