• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.2
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• pp.127-131
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• 2006

A study was carried out to produce antimicrobial peptides from zein treated with pretenses of six kinds. Among the pretenses of six kinds, zein hydrolysate treated with pepsin showed the highest antimicrobial activity. The zein hydrolysate with pepsin was fractionated with membrane filter (30,000 10,000 and 3,000 molecular weight cut-off) and antimicrobial activity was measured for each fractions. Antimicrobial activity appeared greatly in the fraction below 3,000 (molecular weight cut-off) . The fraction was re-fractionated by HPLC and substances of two peaks collected as a sample to measure antimicrobial activity. All of both peaks showed the antimicrobial activity but 1st peak exhibited a consistently higher antimicrobial activity than 2nd peak. Minimum inhibitory concentrations (MIC) were between 2.5 and 3.0 mg/mL. The peptide was heat-stable since antimicrobial activity was maintained after treated with heat for 20 min at $121^{\circ}C$. N-terminal amino acid sequence of peptide fractionated by HPLC was leucine, glutamic acid, proline, phenylalanine, aspartic acid and argenine. These results indicated that peptide isolated from zein hydrosate with pepsin can use as a natural preservative ingredient in food industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.766-772
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• 2007

The enzymatic hydrolysate of skipjack tuna cooking drip with good functionality was prepared by incubation with Alcalase for 30 min. For the preparation of functional seasoning sauce with enzymatic hydrolysate (SSE), the additives, such as concentrated enzymatic hydrolysate (100 mL), yeast extract powder (0.7 g), lactose (0.4 mL), liquid smoke (0.3 g) and sea tangle powder (1.4 g), were added to the enzymatic hydrolysate and boiled before filtration. The proximate composition of SSE was 11.8% for crude protein, 5.77 for pH and 11.9% for salinity. The SSE was higher in the crude protein, while lower in the salinity than commercial seasoning sauce. ACE inhibitory activity ($IC_{50}$) and antioxidative activity (PF) of SSE were 6.2 mg/mL and 1.14, respectively, which were superior to those (9.9 mg/mL in IC50 and 0.91 in PF) of commercial seasoning sauce. The free amino acid content (1,905.2 mg/100 mL) and taste value (58.65) of SSE were higher than in those (712.7 mg/100 mL and 34.30, respectively) of commercial sauce. Total amino acid content of SSE (10,965 mg/100 mL) was higher than that (4,818 mg/100 mL) of commercial sauce. The major amino acids of SSE were glutamic acid (12.2%), proline (11.0%), histidine (10.7%) and glycine (9.9%). The results suggested that SSE could be commercially sold.

• KSBB Journal
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• v.24 no.3
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• pp.312-320
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• 2009

Stable cell preservation is an essential factor in the regenerative medicine for cell therapies and transplantation of biologic materials. In this study, we studied to provide more stable hypothermic preservation by protection of cell damage during the preservation at $4^{\circ}C$. The result of searching for key components that have excellent efficacy in hypothermic preservation of cells, we have identified the fact that the hypothermic preservation adding protein hydrolysates such as yeast hydrolysate is far superior to others. All protein hydrolysates that are derived from animal, plant and microbe sources have superior efficacy, especially the peptides which have molecular weights under 10 kDa have the best efficacy among the components of protein hydrolysate. The protein hydrolysates prevented the decrease of ATP level in the cells caused by hypothermic environment and they inhibited the generation of ROS. Adding antioxidants and control agents of osmotic pressure were showed to have more superior efficacy in hypothermic preservation. Finally, KUL261 solution (DMEM/F12 1 : 1 medium, yeastolate 1%, $\alpha$-tocopherol $100{\mu}M$, dextran 2.5%), the preservation solution developed in this study, showed the best efficacy in both cell viability and cell growth more than other conventional preservation solutions. In conclusion, the improved hypothermic preservation solution that contains the protein hydrolysates as a key component provide the best preservation efficacy. It provides better efficacy than other preservation solutions and will contribute to both the development of regenerative medicine and global commercialization in this therapeutic field.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.45-51
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• 2014

This is to study the effects of various pretreatment methods of agricultural residue, corn stover, and to compare the feature and pros and cons of each method including dilute sulfuric acid (DSA), soaking in aqueous ammonia (SAA), and ammonia recycle percolation (ARP). In order to convert corn stover to ethanol, various pretreatments followed by simultaneous saccharification and co-fermentation (SSCF) were tested and evaluated in terms of ethanol yield. With 3%, w/w of glucan loading using ARP-, DSA-, and SAA-treated solids, SSCFs using recombinant E. coli strain (ATCC$^{(R)}$ 55124) with commercial enzymes (15 FPU of Spezyme CP/g-glucan and 30 CBU/g-glucan enzyme loading) were tested. In the SSCF tests, 87, 90, and 78% of theoretical maximum ethanol yield were observed using ARP-, DSA-, and SAA-treated solids, respectively, which were 69, 58, and 74% on the basis of total carbohydrates (glucan + xylan) in the untreated corn stover. Ethanol yield of SAA-treated solid was higher than those of ARP- and DSA-treated solids. In addition, SSCF test using treated solids plus pretreated hydrolysate indicated that the DSA-treated hydrolysate showed the strongest inhibition effect on the KO11 strain, whereas the ARP-treated hydrolysate was found to have the second strongest inhibition effect. Bioconversion scheme using SAA pretreatment and SSCF can make the downstream process simple, which is suggested to produce ethanol economically because utilization of hemicellulose in the hydrolysate is not necessary.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.243-248
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• 2011

We studied the repeated-batch process for the bioethanol production from the hydrolysate of Ulva pertusa Kjellman using yeast Pichia stipitis, which is able to assimilate C6- and C5-monosaccharides. During 180-hour operations, the repeated-batch process was carried out stably, and the average bioethanol concentration reached 11.9 g/L from about 30 g/L of reducing sugar in the hydrolysate. Meanwhile, the bioethanol yields, based on the reducing sugar and the quantitative TLC analysis, were 0.40 and 0.37, respectively, which corresponded to 78.4% and 72.5% of theoretical value, respectively. Throughout the quantitative process analysis, it was also demonstrated that 39.67 g-bioethanol could be produced from 1 kg of dried Ulva pertusa Kjellman. In this study, we verified that the bioethanol production from the hydrolysate of Ulva pertusa Kjellman was feasible using a yeast Pichia stipitis, particularly during the repeated-batch operation.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1995.11a
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• pp.112-112
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• 1995

• Proceedings of the Korean Nutrition Society Conference
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• 2003.05a
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• pp.198.2-198.2
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• 2003

• Proceedings of the Korean Society of Life Science Conference
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• 2003.10a
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• pp.158-158
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• 2003

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.272.1-272.1
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• 2001

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.11-16
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• 2005

Enzymatic hydrolysis of dark muscle of skipjack was optimized by using response surface methodology. Three factors of independent values were pH (4.2 to 9.8), time (0.6 to 3.4 hrs) and temperature (34℃ to 76℃), and independent values were optical density and brix. The optimum conditions for enzymatic hydrolysis were pH 7.0 to 8.0, 55℃ and 3 hrs. The headspace volatile compounds of reaction flavors using the enzymatic hydrolysate, cysteine and xylose were identified by using the combination of a canister system, gas chromatography and mass selective detector. Among 67 compounds, we identified 8 sulfur-containing compounds and 7 furans which were thought to be highly related to meat-like flavors.