• 한국식품조리과학회지
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• 제21권1호
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• pp.18-23
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• 2005

The effects of soybean oil and cyclodextrin were studied on the quality characteristics and storage of frozen soy yogurt prepared from proteolytic soy protein isolate. The viscosity and overrun of frozen soy yogurt were improved by the addition of soybean oil and cyclodextrin. Upon the addition of cyclodextrin, there was a decrease in the peroxide value of yogurt with subsequent increase by the addition of soybean oil during frozen storage. During the process of storage, there was an increase in the acetone and diacetyl contents, but methanol, ethanol and butanol contents decreased. However, the value of hexanal content was not consistent in the obtained results. Sensory characteristics of frozen soy yogurt such as mouth feel, and overall quality were improved by the addition of cyclodextrin and remained the same frozen storage at $-20^{\circ}C$ for 30 days.

• Journal of Microbiology and Biotechnology
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• 제13권2호
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• pp.191-195
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• 2003

The in vitro glycosylation of pentapeptide (Arg-Lys-Asp-Val-Tyr; RKDVY) and RNase A was carried out using PNGase F (peptide-N-glycosidase F), and the results were analyzed using MALDI-TOF-MS. Aminated N,N-diretyl chitobiose was used as the sugar in the glycosylation reaction, and the amination yield of N,N'-diacetyl chitobiose was about $60\%$. To reduce the water activity and shift the reaction equilibrium to a reverse reaction, 1,4-dioxane or ethylene glycol was used as the organic solvent in the enzymatic glycosylation. A certain extent of nonenzymatic glycosylaton, known as the Maillard reaction, was also observed, which occurs on an arginine or lysine residue when the length of tie sugar residue is one or two. However, the extent of glycosylation was much higher in the enzymatic reaction, indicating that PNGase F can be effectively used to produce glycopeptides and glycoproteins in vitro.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권1호
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• pp.38-42
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• 2002

A chitinase gene (pCHi58) encoding a 58 kDa chitinase was isolated from the Serratia marcescens KCTC 2172 cosmid library. The chitinase gene consisted of a 1686 bp open reading frame that encoded 562 amino acids. Escherichia coil harboring the pChi58 gene secreted a 58 kDa chitinase into the culture supernatant. The 58 kDa chitinase was purified using a chitin affinity column and mono-S column. A nucleotide and N-terminal amino acid sequence analysis showed that the 58 kDa chitinase had a leader peptide consisting of 23 amino acids which was cleaved prior to the 24th alanine. The 58 KDa chitinase exhibited a $98\%$ similarity to that of S. marcescens OMB 1466 in its nuclotide sequence. The chitinolytic patterns of the 58 kDa chitinase released N,N'-diacetyl chitobiose (NAG2) as the major hydrolysis end-product with a trace amount of N-acetylglucosamine. When a 4-methylumbellyferyl-N-acetylglucosamin monomer, dimmer, and tetramer were used as substrates, the 58 kDa chitinase did not digest the 4-Mu-NAG monomer $(analogue\;of\;NAG_2)$, thereby indicating that the 58 kDa chitinase was likely an endochitinase. The optimum reaction temperature and pH of the enzyme were $50^{\circ}C$ and 5.0, respectively.

• 한국식품조리과학회지
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• 제21권2호
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• pp.217-224
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• 2005

The storage characteristics of frozen soy yogurt prepared with hydrolyzed soy protein isolates were evaluated. In order to facilitate lactic fermentation bacteria grow and produce lactic acid as fast rate as possible, soy protein isolate(SPI) was hydrolyzed using two kinds of proteases; bromelain and a-chymotrypsin. The cultural systems employed thereafter for lactic fermentations were Bifidobacterium bifidum or B. bifidum and Lactobacillus bulgaricus. The viable cell counts, normal- and bile acid tolerances from the mixed cultures of B. bifidum and L. bulgaricus decreased sharply during the initial first 3 days of frozen storage and then showed a gradual decrease thereafter. Melt-down percent of the all frozen products have been favorably affected as was shown by less melting at raised testing temperature during 28 days of frozen storage except for the initial 3 days during which a minor change has been observed. Among the various volatile flavor components, the contents of acetaldehyde, acetone, diacetyl and methanol generally increased during the frozen storage. In sensory test, the frozen soy yogurt prepared with a-chymotrypsin and mixed culture of B. bifidum and L. bulgaricus was the most desirable, the highest scores in sourness, bitterness and mouthfeel.

• 약학회지
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• 제44권5호
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• pp.384-390
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• 2000

Metabolism study of the dye, benzidine, was performed by gas chromatography-mass selective detector (GC/MSD) in the urine of rats orally administered 100 mg/kg benzidine. Urine samples were collected in metabolic cages for 0-24, 24-48, and 48-72 hrs. Ten ml of the urine was extracted with XAD-2 resin and the XAD-2 column was eluted with methanol. After evaporation, benzidine and its metabolites were extracted with diethyl ether (for non-conjugated fraction). For conjugated metabolites, $\beta$-glucu-ronidase was added to the aqueous layer that was incubated for 1 hr at 5$0^{\circ}C$ and the aqueous layer was extracted as in non-conjugated fraction. Aliquot of trimethylsilylated derivatives was applied to the GC/MSD. The mutagenicity of benzidine and its acetylated metabolites was tested by histidine/reversion assay. Five metabolites observed and confirmed either by electron impact and chemical ionization modes of the GC/MSD, or authentic compounds were monoacetyl-, diacetyl-, hydroxyacetyl-, hydroxydiacetyl-, and hydroxy-benzidine. Monoacetyl-benzidine was more potent than benzidine in histidine/reversion assay. This data indicates that monoacetylation of benzidine may be one of the metabolites produced in metabolic activation process.

• 실내환경 및 냄새 학회지
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• 제17권4호
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• pp.389-395
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• 2018

The odor substances generated in a feed manufactory operating for the commercialization of animal-vegetable materials were analyzed and the odor reduction efficiency by a chemical scrubber was evaluated. The major causative substances in the feed manufactory comprised about 45.4% of ketone compounds and about 13.3% of aldehyde compounds. On the other hand, the removal efficiencies of diacetyl and acetoin as ketone compounds were 77.3% and 78.1%, respectively, by a chemical scrubber. Additionally, the removal efficiencies of acetaldehyde, butyraldehyde, valeraldehyde, 2-furancarboxaldehyde, and nonanal were 86.0%, 78.9%, 67.4%, 52.8%, and 71.9%, respectively. These rates were higher than the odor generation substance contribution rate as a result of treating the exhaust gas generated from the feed manufactory by the chemical scrubber using 5% of C3. It was also found that xylene, methylcyclopentane, benzene, ethylbenzene, 1,3,5-trimethylbenzene, and decane were almost not removed.

• 한국축산식품학회지
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• 제43권3호
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• pp.540-551
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• 2023

Milk protein concentrate (MPC) is widely used to enhance the stability and texture of fermented dairy products. However, most research has focused on yogurt products, and the effects of MPC on sour cream characteristics remain unknown. Therefore, we investigated the effects of different MPC levels (0%, 1%, 2%, and 3% w/w) on the rheological, physicochemical, microbiological, and aroma characteristics of sour creams in this study. We found that MPC supplementation stimulated the growth of lactic acid bacteria (LAB) in sour creams, resulting in higher acidity than that in the control sample due to the lactic acid produced by LAB. Three aroma compounds, acetaldehyde, diacetyl, and acetoin, were detected in all sour cream samples. All sour creams showed shear-thinning behavior (n=0.41-0.50), and the addition of MPC led to an increase in the rheological parameters (η_a,50, K, G', and G"). In particular, sour cream with 3% MPC showed the best elastic property owing to the interaction between denatured whey protein and caseins. In addition, these protein interactions resulted in the formation of a gel network, which enhanced the water-holding capacity and improved the whey separation. These findings revealed that MPC can be used as a supplementary protein to improve the rheological and physicochemical characteristics of sour cream.

• 치위생과학회지
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• 제8권3호
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• pp.109-115
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• 2008

치과용 가시광선 중합형 복합수지의 광중합효율을 높이기 위해 2종의 새로운 액체형 amine 개시제인 MA, MPT와 현재 가장 많이 사용되고 있는 개시제인 AEM을 CQ, PD, DA에 각각 첨가하고 UDMA의 광중합효율을 알아본 결과 다음과 같은 결론을 얻었다. 1. 조사시간이 증가됨에 따라 amine 개시제의 종류에 관계없이 광중합효율이 점차 증가되었으며, 약 60초까지 조사였을 때에는 광중합효율이 급격히 증가되었으나 그 이상 조사하여도 광중합효율이 크게 증가되지 않았다. 2. AEM, MA와 MPT를 사용하였을 경우 모두 CQ > PD > DA의 순으로 광중합효율이 우수하게 나타났으나 AEM을 사용하였을 때 PD와 CQ는 큰 차이를 보이지 않았다. 3. CQ의 광중합효율은 새로운 광개시제인 MA와 MPT를 사용하였을 때가 범용으로 사용되고 있는 amine 개시제인 AEM을 사용하였을 경우보다 중합효율이 증가하는 결과를 보였다. 4. PD의 광중합효율은 MA와 함께 사용하였을 경우가 가장 높게 나타났으나 AEM의 경우와 큰 차이를 보이지는 않았다. 5. 이상의 결과로부터 MA와 CQ 및 PD를 함께 사용한 새로운 광중합시스템이 광중합효율을 높이는데 효율적인 것을 알 수 있었다.

• Biomolecules & Therapeutics
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• 제24권4호
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• pp.438-445
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• 2016

Cyperi Rhizoma (CR), the rhizome of Cyperus rotundus L., exhibits neuroprotective effects in in vitro and in vivo models of neuronal diseases. Nevertheless, no study has aimed at finding the neuroactive constituent(s) of CR. In this study, we identified active compounds in a CR extract (CRE) using bioactivity-guided fractionation. We first compared the anti-oxidative and neuroprotective activities of four fractions and the CRE total extract. Only the ethyl acetate (EA) fraction revealed strong activity, and further isolation from the bioactive EA fraction yielded nine constituents: scirpusin A (1), scirpusin B (2), luteolin (3), 6'-acetyl-3,6-diferuloylsucrose (4), 4',6' diacetyl-3,6-diferuloylsucrose (5), p-coumaric acid (6), ferulic acid (7), pinellic acid (8), and fulgidic acid (9). The activities of constituents 1-9 were assessed in terms of anti-oxidative, neuroprotective, anti-inflammatory, and anti-amyloid-${\beta}$ activities. Constituents 1, 2, and 3 exhibited strong activities; constituents 1 and 2 were characterized for the first time in this study. These results provide evidence for the value of CRE as a source of multi-functional neuroprotectants, and constituents 1 and 2 may represent new candidates for further development in therapeutic use against neurodegenerative diseases.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.767-774
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• 2010

In this study, the problems of high caloric content, increased maturation time, and off-flavors in commercial beer manufacture arising from residual sugar, diacetyl, and acetaldehyde levels were addressed. A recombinant industrial brewing yeast strain (TQ1) was generated from T1 [Lipomyces starkeyi dextranase gene (LSD1) introduced, ${\alpha}$-acetohydroxyacid synthase gene (ILV2) disrupted] by introducing Saccharomyces cerevisiae glucoamylase (SGA1) and a strong promoter (PGK1), while disrupting the gene coding alcohol dehydrogenase (ADH2). The highest glucoamylase activity for TQ1 was 93.26 U/ml compared with host strain T1 (12.36 U/ml) and wild-type industrial yeast strain YSF5 (10.39 U/ml), respectively. European Brewery Convention (EBC) tube fermentation tests comparing the fermentation broths of TQ1 with T1 and YSF5 showed that the real extracts were reduced by 15.79% and 22.47%; the main residual maltotriose concentrations were reduced by 13.75% and 18.82%; the caloric contents were reduced by 27.18 and 35.39 calories per 12 oz. Owing to the disruption of the ADH2 gene in TQ1, the off-flavor acetaldehyde concentrations in the fermentation broth were 9.43% and 13.28%, respectively, lower than that of T1 and YSF5. No heterologous DNA sequences or drug resistance genes were introduced into TQ1. Hence, the gene manipulations in this work properly solved the addressed problems in commercial beer manufacture.