• Korean Journal of Food Science and Technology
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• v.17 no.4
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• pp.276-282
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• 1985

To characterize bitter peptides in fermented protein foods, peptides were extracted with 2:1 (v/v) chloroform-methand from various samples and separated into fractions I, II, and III by Sephadex G-25 gel chromatography. Amino acid compositions of Mozzarella cheese, soybean paste, and each fraction from the two samples were analyzed to calculate the average hydrophobicity. All the solvent extracts of the food samples had strong bitter taste, although the original samples did not taste bitter. The yield of solvent extraction ranged from 0.08 to 62.50% of total nigrogen of food samples. The average hydrophobicity calculated from the amino acid composition of Mozzarella cheese was 1376 cal/mole, solvent extract 1,623 cal/mole, gel chromatography traction I, 1,797 cal/mole, fraction II, 2,454 cal/mole, and fraction III, 1,559 cal/mole. In the case of soybean paste, the average hydrophobicity of original sample, solvent extract, gel chromatography fraction I, II, and III wre 1,229, 1,654, 1,900,998 cal/mole, respectively. The important amino acids in bitter peptides were leucine, 2016, phenylalanine, proline, and voline.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.646-651
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• 1995

The correlation between the bitter taste and the surface tension was found for bitter tasting, aqueous solutions. By the Szyszkowski's equation, the surface tension (STR) and taste curves (JND) were derived more clearly using the Techplot program. The specific capillary activity (log b values) for bitter tasting solutions are negatively correlated to the recognition threshold. It was shown that a more bitter substances has greater capillary activity. The correlation between the recognition threshold $(log\;C_{1})$ and the substance specific constant (a and b values) of sensory (JND) and surface tension values indicates good agreement. This means that the model of surface area adsorption in the solution/air system can apply also for the sensory model microvillus membrane in the mouth.

• Journal of the Korean Society of Food Culture
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• v.35 no.6
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• pp.597-604
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• 2020

This study examined the bioactive compound content and the antioxidant activities of bitter melon (Momordica charantia Linn.) leaves. The content of vitamin C, beta-carotene, and total carotenoids was 69.77, 45.68, and 65.08 mg/100 g, respectively. To investigate the antioxidant capacity, bitter melon leaves were extracted using various concentrations of ethanol (60, 80, or 100%). Highest content of total polyphenols (18.07 mg gallic acid equivalent/g) and flavonoids (4.53 mg cathechin equivalent/g) was found in the 100% ethanolic extract of the leaves (E100). Also, the E100 extract showed the highest levels of 2,2'azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and α-α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging activities. Reducing power was also the highest (39.21 mg Trolox equivalent/g) in E100 extract. The E100 extract effectively inhibited lipid peroxidation by 91.45% compared to the control group. Also, the E100 extract showed a cytoprotective effect against oxidative stress in HepG2 cells and decreased the generation of intracellular reactive oxygen species. These results suggest that bitter melon leaves could be regarded as a potential source of natural antioxidants.

• Natural Product Sciences
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• v.19 no.4
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• pp.286-289
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• 2013

Phytochemical constituents were isolated from bitter melon (the fruits of Momordica charantia) through open column chromatography. Their structures were identified as ${\beta}$-sitosterol (1), (23E)-$5{\beta}$,19-epoxycucurbita-6,23-diene-$3{\beta}$,25-diol (2), daucosterol (3), uracil (4), and allantoin (5) by interpretation of spectroscopic analysis including MS and $^1H$- & $^{13}C$-NMR. Among them, allantoin (5) was isolated from this plant for the first time.

• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.15-19
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• 2012

A new cyclic peptide (six-membered amino acid), gamakamide-E (L-Leu-L-Met (SO)-L-Me-Phe-L-Leu-D-Lys-L-Phe), was isolated as a strongly bitter tasting compound from cultured oysters, Crassostrea gigas. The molecular formula of $C_{43}H_{61}N_7O_8S$ was deduced from high resolution fast atom bombardment mass spectrometry (HR FAB-MS) ($[M+H]^+$ m/z 836.4356 ${\Delta}$= -2.4 mmu). Its unique structure including a hydantoin structure was firstly elucidated by nuclear magnetic resonance (NMR) analysis. Stereochemistries of constituent amino acids were determined by chiral high performanced liquid chromatography analysis of natural and synthesized peptides.

• KIEE International Transactions on Power Engineering
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• v.3A no.2
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• pp.100-108
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• 2003

This paper presents the design and performance results of a pair of 6-kA high-temperature superconducting (HTS)-copper current leads, in which, over a short length at the warm end (e.g.,77K) of each HTS section, comprised of paralleled Bi-2223/Ag-Au tapes, is operated in the current-sharing mode. Because of their reliance on vapor cooling, the leads are applicable only to liquid helium cooled superconducting magnets such as those used in high-energy Physics accelerators and fusion machines. The experimental measurements have demonstrated that key performance data of the new 6-kA HTS-Copper leads agree reasonably well with those expected from design.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.637-643
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• 2010

For enhancement of apple productivity, the calcium fertilizers to increase the calcium content of fruit, and reduce the incidence of bitter pit in apples are applied. Crushed oyster shell contains a plenty of calcium carbonate, and a very small amount of boron, ferrous, and manganese. A field study was conducted to determine the optimum level of crushed oyster shell for soil nutrient management, and its effect on the induction of bitter pit in cultivar 'Gamhong' apple. The application of crushed oyster shell increased organic matter, available phosphate, and exchangeable cation concentration in soil. We found a significant positive correlation between soil pH, and application level of crushed oyster shell in both top, and subsoils. The incidence of bitter pit in apple fruit at the harvest stage was significantly higher in non treatment and calciummagnesium carbonate treatment than on over applications 4 Mg $ha^{-1}$ for crushed oyster shell. However, the optimum level of crushed oyster shell was 2 Mg $ha^{-1}$, especially considering the soil Ca content, soil pH, fruits weight, and yield. Our results show that the crushed oyster shell can be effective in restoring the soil nutrient balance, and inducing the bitter pit in apple fruit.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.261-265
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• 1993

For the purpose of supplying the information to improve the acceptability of soy paste as the condi-ment, the changes of peptide were determined. The results were as follows; Average peptide length were decreased. It was 102 at 0 day, 15 at 10 day and 4.1 at 180 day. Peptide fraction were the same as in 60 day and 180 day. Low molecular weight peptide were not changed greatly during fermention. Peptide identified in 180 day fermentation were Ala-Ser, Gly-Glu, Glu-Ser, Asp-Glu, Asp- Tyr, Asp-Ala-Ser, Ala-Ser-Glu, Glu-Ser-Ala, and Ala-Lys-Met. In the characteristics of bitter peptide in 180 day fermentation, soy paste itself didn't show bitter taste', solvent extration fraction I'showed bitter taste. After gel chromatography, fraction I, fraction II and fraction III were obtained and fraction II were bitter peptide of low molecular weight. After gel chromatography', solvent extration fraction 2'(water extration) were divided into fraction IV, V, VI,VII and VIII. Fraction IV, V and VI showed bitter taste. Amino acids composition of the fractions showing bitter taste were like that; fr. 1: Glu- (Asp, Pro, Val, lie or Leu)-Met fr. II Pro-(Glu, Val, Phe)-lle or Leu fr. IV: Glu-(Asp, Ala, Tyr, Leu of lie)-Phe fr. V: Ala-(Met, Glu, Pro)-lle or Leu fr. VI: Asp-(Phe, Ser, fly)-Val.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.401-411
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• 2015

Bitter melon (Momordica charantia L.) has various biological functions, including anti-diabetic, anti-cancer, anti-inflammatory, anti-viral, and antioxidant activities. However, the development of foods using bitter melon (BM) is unexplored due to its bitter taste. In this study, BM pickle was prepared, and changes in quality characteristics and antioxidant activity during ageing were determined. After 4 weeks of ageing, pH levels, salinities, soluble solids, and reducing sugars of BM pickle decreased, whereas acidities increased. In addition, total viable, lactic acid bacteria, and yeast viable cell numbers greatly increased until 1 week, after which they slightly decreased. Levels of soluble phenolics increased during ageing, antioxidant activity increased accordingly. Crude protein, K, and P contents of pickles were lower than in raw material of BM, whereas crude fat and Na contents increased. Corn silk extracts were added to BM pickle during ageing in order to improve the bitter taste and flavor. The best sensory quality was obtained by adding 0.25% corn silk extracts.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.71-75
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• 2016

The experiment was carried out to examine the effects of planting date on the growth and marketable yield of bitter gourd grown in rain-shield plastic houses. Bitter gourd cv 'Dragon' seedlings were separately transplanted during the months of June, July and August, 2015. The training method of all plants was made with four lateral vines and pinching the main vine. Lateral length of plants exhibited no significant difference between each planting date. However, bitter gourd planted in June had significantly higher main stem diameter than those treatments planted on August. The application of planting date was found effective in increasing marketable yield and number of fruits. June, as a planting date, had the highest marketable yield (6,439kg/10a), whereas bitter gourd planted in August had the lowest yield (870kg/10a) which were also consistent in terms of the number of fruits. Fruit length and diameter had no significant differences as affected by treatments. Therefore, planting date of bitter gourd in June was effective in increasing yield of fruit in rain-shield plastic house conditions.