• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.66-71
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• 1981

In order to study the decomposition process of glycogen and protein of oyster during fermentation with salt, and the relationship between their breakdown products, the amounts of free reducing sugars and lactic acid were determined, and amino acid compositions were analysed. In addition, the amount of the available lysine which may help us to estimate the reaction of the free reducing sugars with the free amino acids was also determined. Glycogen and protein were gradually decomposed to free reducing sugars and lactic acid, and free amino acids, respectively, and the available lysine was slightly decreased during the fermentation process. Glutamic acid, aspartic acid, lysine and proline were relatively rich in the amino acid com-position of raw oyster protein while amino acids such as tryptophan, methionine, histidine and tyrosine were poor. It was noted that the decreased amino acids in the protein from the fermented oyster were valine, histine, isoleucine and lysine. As a respect to the free amino acids, proline, taurine, glycine, glutamic acid and alanine were abundant in the raw oyster and reached up to $69\%$ of the total fret amino acids. In the fermented oyster, proline, glutamic acid, glycine, alanine, aspartic acid and lysine were prevalently contained and marke about $65\%$ of the total free amino acids. The contents of free amino acids such as lysine, arginine, aspartic acid, glutamic acid, cysteine, isoleucine and tyrosine increased during fermentation while those of taurine, proline and leucine decreased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.696-701
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• 2002

Optimal conditions for preparing of chitooligosaccharides from chitosan with cellulase was researched by response surface methodo-logy, Penicillium funiculosum derived cellulase was most effective for chitooligosaccharides production as the point of hydrolyzing activity and commercial utility. The result which measures the change of degrading ratio at time course, 10 hr reaction showed a exponential increase and after that time degrading ratio was not changed. The optimal conditions determined by response surface methodology with central composite design of total 26 species were $0.5\%$ of chitosan, 143 U enzyme, 49$^{\circ}C$ of reaction temperature, 13.2 hr of reaction time and pH 3.8. Major chitooligosaccharides produced from chitiosan on optimal conditions were dimer and trimer.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.596-602
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• 1993

The Characteristics of Shinsunchalbyeo(Japonica) and Hangangchalbyeo($J{\times}Idica$) starches including physicochemical properties, differential scanning calorimetry(DSC) and enzymatic digestion of lintnerized starches were investigated. Degree of hydrolysis of Hangangchalbyeo starch with 2.2N HCI for 48hr was higher than that of shinsunchalbyeo starch. Absorbance at ${\lambda}_{max}$ 680nm, and ${\lambda}_{max}$ of iodine stained starch decreased upon acid treatment. But water binding capacity, swelling power and solubility considerably increased as hydrolysis progressed. Relative crystallinity of two starches increased with acid treatment, and that of Shinsunchalbyeo starch was higher than that of Hangangchalbyeo starch. DSC data continuously decreased for lintnerization periods, and those of Shinsunchalbyeo starch. DSC data continuously decreased for lintnerization periods, and those of Shinsunchalbyeo starch have higher than those of Hangangchalbyeo starch. The onset temperature of starch by DSC continuously decreased by treatment, but conclusion temperature increased until 24hr and then decreased. The enthalpy for gelatinization decreased for both starches. Degree of hydrolysis of lintnerized Shinsunchalbyeo starch with glucoamylase was slightly higher than that of Hangangchalbyeo starch.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.63-67
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• 1995

Broiler processing waste(offal) was homogenized and treated with the combination of acids. The offal was autolyzed(ensiled) at $25^{\circ}C$ for 72 hrs and analyzed for pH and fatty acid profile. The proximate composition and microbial content change of the autolyzed offal by mixing with wheat bran and ovendrying were evaluated. The initial pH value of the homogenized offal, 6.52 came down to 2.75 within 5 min after acidification and increased silightly to $3.06{\sim}2.92$ during autolysis. The proximate composition and fatty acid profile of the autolyzed offal were not substantially different from the unautoylzed offal. However, the log CFU(colony forming units)/g of total plate counts and fungal counts decreased from 7.45 and 7.11 to 3.39 and 2.03 after autolysis, respectively.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1048-1053
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• 1997

Modified mordenites by HF treatement, which have different $SiO_2/Al_2O_3$ ratio, and those mixed with $\gamma$-alumina are prepared and used for catalytic cracking of triphenylmethane(TPM) in micro-activity tester(MAT). Dealumination of mordenites decreased the acid content but developed secondary mesopores. The conversion and the selectivity of benzene over modified mordenites with the mesopores were increased. However, for the further dealuminated mordenites, they decreased due to the destruction of pore structure and low acid amount. Accordingly, the maximum cracking activity and the maximum selectivity of benzene were obtained about 17 $SiO_2/Al_2O_3$ ratio of modified mordenites. The modified mordenites mixed with alumina enhanced the cracking activity of TPM compared with the pure mordenites. It can be explained that TPM is cracked at active sites with in large pores of alumina firstly and further cracked into small molecules in zeolite pores as step mechanism of catalytic cracking.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.103-117
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• 2017

In longitudinal data analysis, the serial correlation of repeated outcomes must be taken into account using covariance matrix. Modeling of the covariance matrix is important to estimate the effect of covariates properly. However, It is challenging because there are many parameters in the matrix and the estimated covariance matrix should be positive definite. To overcome the restrictions, several Cholesky decomposition approaches for the covariance matrix were proposed: modified autoregressive (AR), moving average (MA), ARMA Cholesky decompositions. In this paper we review them and compare the performance of the approaches using simulation studies.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.432-435
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• 2006

전 세계적으로 방대하게 배출되는 도축 부산물인 우모는 높은 영양적 가치를 가짐에도 불구하고 현재 사용하는 물리화학적 처리법의 여러 단점으로 효율적으로 이용되지 못하고 있는 실정이다. 그 결과 2차 오염을 발생시키지 않는 경제적 방법인 생물학적 처리에 대한 연구의 필요성이 커지고 있다. 본 연구에서는 그러한 방법 중 대표적인 방법으로 미생물이 생산하는 keratinase를 이용한 생분해에 대해 연구를 하기 위해 경남 일대 퇴비화 볏짚에서 keratinolytic protease 생성능이 우수한 균주인 RS7을 분리하였고 생화학적 동정법과 16S rDNA를 이용한 동정결과 B. pumilus로 동정되었다. 본 실험에서 분리된 B. pumilus는 기존에 활발히 연구되어 있지 않는 균주로써 native feather 분해도가 기존에 알려진 Bacillus 속들이 3일 정도에서 분해 완료되는 것과는 달리 36시간 ${\sim}$48시간 내에 깃대까지 완전히 분해하였다. 또한 분리 균주의 경제적인 분해능을 토대로 분해산물이 식물 생장에 주는 영향과 아미노산 함유량을 검토한 결과 기존의 화학적 분해에 의한 분해산물보다 아미노산 함유량이 4배가량 많았으며 식물 생장에 있어서도 생장율과 개화시점으로 미루어볼 때 비료로써의 역할을 수행할 수 있었다.

• The Korean Journal of Applied Statistics
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• v.33 no.3
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• pp.281-296
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• 2020

Repeated outcomes from the same subjects are referred to as longitudinal data. Analysis of the data requires different methods unlike cross-sectional data analysis. It is important to model the covariance matrix because the correlation between the repeated outcomes must be considered when estimating the effects of covariates on the mean response. However, the modeling of the covariance matrix is tricky because there are many parameters to be estimated, and the estimated covariance matrix should be positive definite. In this paper, we consider analysis of multivariate longitudinal data via two modeling methodologies for the covariance matrix for multivariate longitudinal data. Both methods describe serial correlations of multivariate longitudinal outcomes using a modified Cholesky decomposition. However, the two methods consider different decompositions to explain the correlation between simultaneous responses. The first method uses enhanced linear covariance models so that the covariance matrix satisfies a positive definiteness condition; in addition, and principal component analysis and maximization-minimization algorithm (MM algorithm) were used to estimate model parameters. The second method considers variance-correlation decomposition and hypersphere decomposition to model covariance matrix. Simulations are used to compare the performance of the two methodologies.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.119-120
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• 2000

젓갈은 어패류의 육, 내장, 생식소 등에 식염을 가하여 부패를 억제하면서 자가 소화 및 미생물의 작용에 의하여 원료를 적당히 분해시켜 숙성시킨 제품으로 발효과정 중에서 생성된 유리 아미노산이나 저분자 펩타이드와 각종 방향성 성분에 의해 특유의 감칠맛과 풍미를 지니고 있다. 그러나 젓갈로 사용되고 있는 어류 중에서 특히 적색육 어류는 선도 저하와 더불어 증가된 Proteus morganii와 같은 세균에 의해서 생성된 decarboxylase의 탈탄산 반응에 의해 아미노산이 분해되어 유독 amine물질을 생성한다. (중략)