• Proceedings of the Korean Society of Life Science Conference
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• 2001.06a
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• pp.3-41
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• 2001

단백질의 부분 가수분해는 산성 음료에서의 용해도 증가, 환자들의 소화력과 알러지 내성의 개선, 다른 기능적 특성의 개발 등을 위하여 식품산업에 널리 이용되고 있다. 그러나 우유 단백질이나 대두 단백질과 같은 몇 가지 단백질들은 가수분해에 의하여 강한 쓴맛을 형성한다, 단백질 가수분해물의 쓴맛에 관한 연구는 1950년대 초에 시작되었으며, 여러 가지 원료로부터 쓴맛물질이 분리되었다. 이들 단백질 가수분해물의 쓴맛 물질은 올리고펩타이드로 알려져 있으며, 펩타이드 분자를 구성하는 소수성 아미노산의 존재와 밀접한 관계가 있는 것으로 보고되고 있다. 본 연구에서는 최근에 발달된 분석기술과 생명공학적 기법으로 E. coli에서 생산한 콩 단백질 단일 subunit를 이용하여 효소적 가수분해물의 분자구조를 확인하고자 하였다. 탈지대두박으로부터 115 glycinin와 E.coli떼서 발현된 proglycinin을 각각 90%, 97%의 정제도로 분리하여 이들 단백질을 trypsin으로 각각 가수분해하였다. 115 glycinin은 효소/기질 비 3%에서 4시간 가수분해에 의해 $14.0{\times}10^{-5}$ M quinine-HCI equivalent의 강한 쓴맛을 나타내었으며, 12%의 가수분해도(DH)를 나타내었다. 대두 단백질의 쓴맛 성분을 확인 위하여 이미 아미노산 서열이 밝혀진 11S glycinin과 proglycinin 가수분해물에서 GP-HPLC, $C_{18}$ RP-HPLC 등을 통하여 쓴맛 peptide들을 분리하였다. 각각의 분획은 다시 21개의 peptide로 분리되어 그 서열이 결정되었으며 이중 RP와 GI는 이미 알려진 쓴맛 dipeptide였고, LAGNQEQE, SAEFG, NALPE, KLHENIAR, GMIYPG 등이 주된 쓴맛 Peptide로 확인되었다. 이들은 11S glycinin의 5개의 subunit 중에서 그 위치가 확인되었다. Proglycinin 가수분해물에서도 11S glycinin과 같은 방법으로 7개의 쓴맛 peptide가 분리되었다. 이들은 $A_{1a}B_{1b}$의 아미노산 서열 중에서 37-42, 103-110, 164-167, 323-327, 367-373의 위치에 분포하고 있었으며, NALKPD, IYPGCPST, SlDT, HNIGQT, NAMFVPH의 서열을 나타내었다. 분리된 쓴맛 peptide 중에서 가장 쓴 두 분회의 peptide를 합성하여 관능 검사한 결과, NALPE는 매우 쓴맛을 내는 peptide로 확인되었다.

• Food Science and Preservation
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• v.30 no.4
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• pp.663-668
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• 2023

Ginseng root is a medicinal plant widely used in Korea for its immunity enhancing and anti-fatigue properties. However, its bitter taste has a negative impact on the expansion of the ginseng market. In this study, we determined the bitter tasting compounds of ginseng using an electronic tongue. The results of measuring bitterness showed that phenolic compounds and polyacetylenes of ginseng had low bitterness. On the other hand, the bitterness was strong in ginsenosides and alkaloids of ginseng. Among them, the bitterness of ginseng was higher in ginsenosides than in alkaloids. Theses results suggest that ginsenosides have a significant affect on the bitter taste of ginseng.

• The Korean Journal of Mycology
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• v.20 no.4
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• pp.285-288
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• 1992

The species of genus Tylopilus were collected from the areas around Kwangrung, Kapyung, and Mt. Backyang in Korea from 1988 to 1991. Description and illustrations of noteworthy three taxa of Genus Tylopilus were made during this period. T. ballouii, T. ferrugineus and T. castancieceps are newly described in Korea.

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.716-722
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• 2014

Aminopeptidase-active fractions from crude extract of the hepatopancreas of a common squid (Todarodes pacificus) were obtained using acetone (AC; 30-40%) and ammonium sulfate precipitation (AS; 60-70% saturation), anion exchange (AE-II; 0.2 M NaCl) and gel filtration chromatography (GF-I; 30-50 kDa), respectively. The debittering capacity of GF-I fraction based on the aminopeptidase activity (89.2 U/mg), recovery (56.6%) and sensory evaluation (1.0) was better than that of other fractions. Release of amino acids increased as incubation time was increased, and the bitterness of the enzyme reaction mixtures decreased. Incubation with the GF-I fraction for 24 h resulted in the hydrolysis of several peptides, as revealed by reverse-phase HPLC profiles. Peaks 3, 5 and 6 showed the decreased area (%), whereas peaks 1, 2 and 4 showed the increased area. The GF-I fractions were found to be suitable for reducing bitterness in protein hydrolysates by catalyzing the hydrolysis of bitter peptides.

• Korean journal of food and cookery science
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• v.10 no.1
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• pp.45-50
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• 1994

Conventional Doenjang, three kinds of Improved Doenjang(A; koji: soybean: salt=53: 100: 33, B; koji: soybean: salt=100: 100: 40, C; koji: soybean: salt= 200: 100: 40) prepared with different ratio of koji and salt were made to study the changes in the general contents, characteristics bitter peptides, correlations between bitterness and overall eating quality. 1. Total nitrogen contents increased a little, and amino nitrogen contents in all samples increase markedly. Especially, Amino nitrogen contents of conventrional Doenjang increased more than others. Reducing sugars of doenjang prepared with Asp. oryzae were higher than conventional Doenjang and increased throughout the aging period and Doenjang prepared with Asp. oryzae were more acidic. 2. To characterize bitter peptides in fermented Doenjang, peptides were extracted with 2: 1(v/v) chloroform-methanol and separated by Gel chromato-graphy with Sephadex and TLC. After Gel chromatography and TLC, each fraction examined presence of bitterness and evaluated intensity of bitterness. Amino acid composition of the fractions showing bitter tastes were as follows. Conv. peak 1-1 Trp-(Asp, Arg, Thr, Ser, Glu, Pro)-Phe Imp. A peak 1 Trp-(Glu, Val, Arg, lie)-Phe Imp. B peak 1 Trp-(lie, Pro, Asp, Lys, Val, Glu)-Trp. Imp. C peak 1-2 Trp-(Try, Thr, Glu, Pro, Gly)-Phe 3. Sensory evaluation revealed that correlation coefficient between bitterness and overall eating guality was not high.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.82-83
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• 2002

1999년 전남 여수지역의 가막만에서 양식한 굴을 원료로 가공한 통조림과 냉동품은 강한 쓴맛을 나타내었으며, Lee(1995)는 이들 굴로부터 쓴맛 성분을 분리 정제하여 5개의 peptide를 분리하여 보고하였다. 이들 성분은 쓴맛 이외에는 별다른 활성이 없었고, 그 후에도 이러한 사례는 보고되지 않아 대수롭지 않게 생각하였으나, 이중양적으로 많았던 1개의 성분에 대하여 발견된 지역인 가막만의 명칭에 유래하여 Gamakamide-E로 명명하고 NMR 및 합성에 의하여 구조를 해명하였기에 보고한다. (중략)

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.205-208
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• 2001

The bitterness of brewers yeast slurry decreased by washing with mild caustic soda solution followed by washing with 0.85% (w/v) NaCl solution The higher concentration of caustic soda was, the lower the bitterness unit(BU) of washed yeast slurry was. The lethal rate of yeast cells increased. When the concentration of caustic soda solution increased from 0.05%(w/v) to 0.25%(w/v), the BU of brewers yeast slurry was decreased from 45 to 3, but yeast cells viability decreased from 93% to 0%. The optimum washing conditions of brewers yeast slurry were as follows: the concentration of caustic soda solution was $0.07{\sim}0.1%$(w/v) and the contact time of brewers yeast slurry with caustic soda was $10{\sim}20$ minutes. The similar washing effect was obtained when the brewers yeast slurry was washed with 20%(v/v) ethanol solution.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.466-473
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• 2016

This study was performed to investigate the reduction in bitter taste and quality characteristics by pretreatments (brining; 1, 5% and blanching; 1, 3 min) in pickled bitter melon, respectively. We prepared picked bitter melon samples at 1%-1 min, 1%-3 min, 5%-1 min, 5%-3 min. Total polyphenol and total flavonoid contents were found to be the highest in 5%-1 min at $14.23{\pm}0.40mg\;CE/g$ (dry) and $4.46{\pm}0.10mg\;RE/g$ (dry), respectively. L-ascorbic acid level was the highest in control samples. Arginine and glutamic acid were increased by brining and blanching. ABTS and DPPH radical scavenging activity were found to be the highest at $43.60{\pm}0.40$ and $44.88{\pm}0.20%$ at 5%-1 min, respectively. ${\alpha}-glucosidase$ inhibitory activity was the highest at 5%-1 min. The a value was statistically different, whereas L and b values were similar among different pretreatments. Hardness in pretreated samples was decreased as compared to that in the control. Among sensory evaluations, 'color' did not indicate any statistical difference, while 'texture', 'bitterness preference' and 'overall preference' increased with pretreatments, and 'bitter intensity' decreased.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.751-761
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• 2016

In order to reduce the bitter taste of red ginseng extract(RGE), inclusion complexes(RGE-CD) of the extract with ${\alpha}$-, ${\beta}$-, ${\gamma}$-cyclodextine after acetic acid treatment at the steam process were prepared and studied for their taste by an electronic tongue. By complexation, the bitter taster- reducing efficacies of ${\alpha}$-CD and ${\beta}$-CD were much lower than that of ${\gamma}$-CD. This study suggested that by processing red ginseng with acetic acid it is possible to enhance the yield of both ginsenoside $Rg_3$ and nonpolar ginsenosides. Taste such as bitterness, sourness, saltiness, umami and sweetness of the red ginseng extract with different amounts of ${\alpha}$-CD, ${\beta}$-CD and ${\gamma}$-CD were checked using an electronic tongue. As a result, REG-${\gamma}$-CD10, prepared using 10%(w/w), showed significantly lower bitter taste than those of the other samples.

• Food Science and Preservation
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• v.14 no.6
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• pp.722-726
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• 2007

Extracting and analytical conditions of curcumin, and removal of bitterness substance from Curcuma longa L. were investigated. Absorption maxima was shown to be 424 nm at methanol solvent. Optimal conditions for analysis of curcumin was Zorbax eclipse $C_{18}$ column ; mobile phase, 75% MeOH ; flow rate, 0.8 mL/min ; wave length, UV 424 nm. Curcumin component was analyzed to be the highest content in methanol extract. In all samples, extraction yield by heating was shown to be effective as compared to room temperature. Curcumin contents of methanol and ethanol extracts in extraction of room temperature were 14.4 and 14.2 times higher than that of water extract, respectively. Two hot solvent extracts has a high curcumin content being 150 mg% as compared to room temperature. Extracting time was an effective condition when it was extracted for 60 minutes for elevating the curcumin content of water and methanol extracts. Bitter substance (BS) was markedly decreased in water extract by heat treatment of above $80^{\circ}C$. BS was weak in $121^{\circ}C$ treatment than in room temperature and it was however strong in $100^{\circ}C$ treatment. RT and $70^{\circ}C$ heat treatment were not different in BS intensity.