• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.277-285
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• 1997

Kluyveromyces marxianus var. marxianus isolated as an inulin-assimilating microorganism produces inulin fructotransferase (inulaseII) which catalyses the conversion of inulin into di-D-fructofuranose 1, 2' : 2, 3' dianhydrde (DFAIII). The DFA produced by the organism was isolated by using active carbon column, and identified as DFAIII by high performance liguid chromatography. The culture medium giving maximum inulaseII production was found to consist of 1% sucrose and 0.75% yeast nitrogen base (YNB). The inulasell production was induced by inulin or sucrose as a carbon source and increased by addition of YNB as a nitrogen source. Optimal initial pH of the culture medium, culture temperature and medium volume for the enzyme production were pH 4.7, 30$\circ$C and 140 ml, respectively. Under the optimal conditions described above, the enzyme activity in the culture supematant reached 4.2 units/ml after cultivation for 36 h. The DFAIII was accumulated at 13.25 mg/ml after 48 h of culture in the Jerusalem artichoke tuber medium.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.135-143
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• 2014

Exopeptidase active fractions from the hepatopancreas of the Argentina shortfin squid Illex argentinus, were obtained with acetone (AC 30-40%), ammonium sulfate (AS 60-70% saturation), anion exchange chromatography (AE-II, 0.2 M NaCl) and gel filtration chromatography (GF-I, 30-50 kDa) fractionation methods. A bitter peptide solution that has a bitterness equivalent to that of 2% glycylphenylalanine and prepared by tryptic hydrolysis of milk casein, was treated with the exopeptidase active fractions. The GF-I fraction was the best based on aminopeptidase activity (35.3 U/mg), percentage of recovery (30.7%) and a sensory evaluation (1.7). The amount of released amino acids increased as incubation time 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 the reverse-phase high performance liguid chromatography profile, with three peaks (3, 5 and 6) decreasing in area (%) and three peaks (1, 2 and 4) increasing in area (%). Therefore, the GF-I fraction appeared to be ideally suited to reduce bitterness in protein hydrolysates by catalyzing the hydrolysis of bitter peptides.

• Food Engineering Progress
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• v.14 no.2
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• pp.159-165
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• 2010

Red ginseng tail roots (9.8 g water/100 g sample) were puffed at 7, 8, 9, and 10 $kg_{f}/cm^{2}$ using a rotational puffing gun. Puffed red ginseng was extracted with 70% ethanol, and the concentrated extract was successively partitioned with diethyl ether, n-butanol and $H_{2}O$. Two unknown ginsenosides from puffed red ginseng were found at 63 and 65 min of retention time in HPLC chromatogram suggesting that chemical structure of some ginsenosides might be altered during the puffing process. Identification of two unknown compounds was carried out using TLC, HPLC and NMR. Two major compounds were isolated from TLC. According to TLC result, compound I was expected to be the mixture of ginsenosides Rk1 and Rg5, and compound II was expected to be a 20(S)-ginsenoside $Rg_{3}$. Three compounds were isolated from n-butanol fraction through repeated silica gel and octadecyl silica gel column chromatographies. From the result of $^{1}H$- and $^{13}C$-NMR data, the chemical structures of unknown compounds were determined as ginsenoside $Rg_{5}$ and 20(S)-ginsenoside $Rg_{3}$. Unfortunately, ginsenoside $Rk_{1}$ could not be separated from ginsenoside-$Rg_{5}$ in the compound I. It was carefully reexamined using HPLC and confirmed that the last unknown compound was ginsenoside-$Rk_{1}$.

• Journal of Food Hygiene and Safety
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• v.24 no.2
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• pp.169-173
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• 2009

A survey of total aflatoxin levels was conducted on 145 samples(carthamiflos, thujae semen, giycyrrhizae radix et rhizoma) collected in Yakyeang markets in Seoul. Aflatoxin levels were quantified by the immunoaffinity column clean-up method followed by performance liguid chromatography(HPLC)-fluorescence detector(FLD). Aflatoxins were found in 10(6.9%)samples including 5 Arecae semen, 4 Thujae semen, 1 Zizyphi semen with a range of $0.45{\sim}79.15\;{\mu}g/kg$. Generally These results show that the contamination level of aflatoxins in Herb Medicines consumed in Korea is high compared with the standard in Korea Herb Medicine Code($10\;{\mu}g/kg$ as aflatoxin B1). It is considered that aflatoxin concentration was increased in herb medicines during a storage and drying in herb medicines examined