• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.547-552
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• 1988

Aminoacylase immobilized on chitosan was applied for optical resolution of DL-amino acids. Optimun pH's for hydrolysis of N-ac DL Met, N-ac DL Try and N-ac DL Phe by immobilized aminoacylase were 8.0, 7.0, and 7.5, respectively. The pH stability of immobilized aminoacylase was less than that of soluble enzyme, while there was no difference in thermostability between immibilized and soluble enzymes. The reaction rate of immobilized enzyme was maximum, when concentrations of N-ac DL Met, N-ac DL Try and N-ac DL Phe were 0.05, 0.03 and 0.05M, respectively. Continuous resolution of M/20 N-ac DL amino acids with immobilized aminoacylase packed in a column resulted in 100% hydrolysis upto space velocity $2.0\;at\;45^{\circ}C$, and the half-life of the column at space velocity 5.0 was about 25 days. The yield of L-Met, L-Try and L-Phe recovered from 2 liter of column effluent were 57%, 52% and 52%, respectively.

• Clean Technology
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• v.18 no.2
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• pp.216-220
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• 2012

The objective of the present study was to evaluate catalytic performance of a commercial catalyst (Co/$ZrO_2-Al_2O_3$) for the decomposition of perfluorinated chemicals in a pilot scale reactor containing 30 L of catalysts. At a reaction condition of GHSV $1,800h^{-1}$, $T_{95}$ of $SF_6$ was increased from 580 to $610^{\circ}C$ with increasing of $SF_6$ concentration from 1,000 to 10,000 ppm. $T_{95}$ of $SF_6$ in catalytic decomposition was much smaller than that of thermal decomposition ($1,600^{\circ}C$). The 99% conversion of $SF_6$ was maintained for 72 hours a reaction temperature of $650^{\circ}C$. In order to maintain the $SF_6$ conversion more than 99%, it is necessary to operate at a reaction condition of GHSV less than $2,000h^{-1}$. An operating temperature of $710^{\circ}C$ was required to achieve >95% destruction of the $CF_4$, which was much higher than that of catalytic decomposition of $SF_6$.

• Journal of Life Science
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• v.18 no.3
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• pp.403-408
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• 2008

In this study, we compared with 80% ethanol extracts from peel of Poncirus trifoliata (PTP) and peel of Citrus junos (CJP) against antioxidant and immune activities. Total phenolics and flavonoids contents in PTP extracts were $60.75{\pm}1.15$ and $33.75{\pm}0.15$ mg/l00 g, respectively, and those were lower than CJP extracts. Antioxidant activities of PTP were increased with the more concentration, and were similar to CJP. Antioxidant activities of PTP were increased with increasing of concentration, and were similar to those of CJP. The NO production in macrophage cell lines were increased in a dose-dependent manner, until 5 mg/ml of CJP and 1 mg/ml of PTP compared with control cells, but decreased at higher concentrations. The proliferation of mouse spleen cells were increased in a dose-dependent manner, until 1 mg/ml of CJP and PTP compared with control cells but decreased at higher concentrations. The NO production in macrophage cell lines treated with PTP and CJP were increased in a dose-dependent manner, compared with untreated control cells until the concentrations of $1{\sim}5$ mg/ml (CJP) and 1 mg/ml (PTP) but decreased at higher concentrations than that. The proliferation of mouse spleen cells treated with PTP and CJP were increased in a dose-dependent manner, compared with untreated control cells until the concentration of 1 mg/ml but decreased at higher concentrations than that.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.854-859
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• 1997

In order to compare physicochemical properties of aqueous extract in 3 beans (small red bean, mung bean, black soybean), proximate composition, free sugars, free amino acids, minerals, absorbance and surface refractance color were investigated. Regardless of raw materials composition, the 3 beans extracts had similar proximate compositions. Free sugar analysis showed that fructose, glucose, sucrose, maltose, raffinose and stachyose were varied among the extracts. Raffinose and stachyose were the major sugar and fructose was measured only in black soybean and glucose was merely found in small red bean. Seventeen free amino acids in beans extract were analysed in the extracts. Among the free amino acids, arginine, aspartic acid, glutamic acid and serine were the main amino acids. Black soybean extract had maximum absorbance at 460 nm and 540 nm. L value of black soybean extract was lower than those of small red bean and mung bean.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.520-524
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• 1995

ATP related compounds, ammonia, VBN, pH and sensory quality of shrimps were determined to evaluate quality changes during iced and frozen storage. ATP related compounds were determined by HPLC, ammonia by ammonia ion specific electrode, VBN by micro-diffusion method, pH by pH meter, sensory quality by multiple comparison test with 30 panelists. K value of ice stored shrimps gradually increased to 20% for 8 days, and then increased more rapidly, whereas that of frozen stored shrimps increased slowly for 7 months. Ammonia contents in ice stored shrimps increased slowly for 6 days and then rapidly after 8 days storage, whereas that in frozen stored shrimps increased slowly for 8 months. VBN contents in ice stored shrimps increased slowly for 10 days and then rapidly after 12 days. VBN contents in frozen stored shrimps slightly increased for 6 months. Sensory scores of taste and color of shrimps marked lowered values after 6 days storage in ice, and after 6 and 7 months frozen storage, respectively. Sensory flavor scores of stored shrimps had significant correlations with K value, ammonia, pH and VBN. These results indicated that ammonia contents in stored shrimps, rapidly determined by an ammonia electrode, could be used as a quality index of shrimps.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.678-684
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• 2005

Extraction conditions, spectrometric, and sensory properties of pigment extracts from green discolored garlic (GDG) were studied for development of green index to evaluate degree of green discoloration of garlic. GDG pigments were extracted using polar solvents, such as methanol, ethanol, and water. Methanol with 1% HCl resulted in highest extraction of green pigments. Extraction of pigments was affected by temperature, and extracted pigments were partially destroyed at high temperatures. Optimum conditions for extraction of green pigments were $20^{\circ}C$ for 30 min. Because green pigments are unstable at room temperature, and no method has been reported to evaluate degree of green discoloration of garlic, color chart was designed by mixing varying amounts of control and GDG. High correlation was observed between sensory scores and "a" value of color chart samples (y=-3.465x - 11.676) with $R^2$ of 0.993. Green index (GI) was developed based on linear regression equation between sensory scores and "a" values. Sensory panel recognized green discoloration of garlic at $GI{\geq}3.0$. GI developed in this study could be utilized to evaluate degree of green discoloration of garlic during cold storage and distribution of garlic.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.557-561
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• 2005

Effects of natural preservatives on quality and shelf-life of fresh pork were investigated by evaluating changes in physicochemical properties, sensory evaluation, and mcrobial properties during storage. Acidity and VBN values of pork with preservatives were lower than those of control. Total bacterial count of pork with preservatives was significantly lower than that of control during storage. Sensory results showed pork with preservatives had lower sensory color and off-flavor scores than control. Changes in pH, VBN, total bacterial count, coliform group, and sensory evaluation revealed pork with preservatives showed less quality changes than control during storage, regardless of storage temperature. Results indicated that addition of preservatives to pork increased shelf-life by 7 days at $4^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1583-1588
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• 1999

Garlic pieces without peeling were subjected to hot air heating at $60{\sim}90^{\circ}C$ for 30 min. and microwave oven heating for 10 sec to reduce the strength of garlic flavor. Volatile compounds of the treated garlic were decreased, as the heating temperature was raised. Garlic heated at 70, 80 and $90^{\circ}C$ had 20%, 31% and 49% less volatile compounds, respectively, compared to those of the control. Microwave oven heating revealed a similar trend to those heated at $60{\sim}80^{\circ}C$. As the heating temperature was raised, glucose, fructose and fructooligosaccharide contents in the heated garlic were decreased. Pyruvic acid contents in garlic, a degradation product of alliin, was decreased as the heating temperature was raised, but contents of the other organic acids were not affected. Arginine, the main amino acid in garlic was decreased by the hot air heating, but was not affected by the microwave heating. Glutamic acid and tyrosine contents were decreased in all the treated garlic samples.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.102-110
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• 2000

Peeled garlic was stored at $-18^{\circ}C\;and\;-40^{\circ}C$, respectively and changes in main quality factors during storage were determined for $15{\sim}16$ months. The puncture force measured by texturemeter was $2709{\pm}368$ G.S at the beginning of storage and did not change significantly after the 15 months storage. Drip losses of stored garlic were 0.4% and 0.7% at $-18^{\circ}C\;and\;-40^{\circ}C$, respectively. Major flavor compounds of garlic analyzed by GC and GC/MS, such as diallyl disulfide, 1,3-dithiane, diallyl sulfide, 2-butanal, were not changed in their quantity during the frozen storage. The contents of cysteine, valine and tyrosine increased slightly notwithstanding the storage temperature. Sucrose content slightly decreased, but glucose and fructose tended to increase in garlic stored at $-18^{\circ}C$. The content of pyruvic acid, degradation product of alliin, did not change during storage at both storage temperatures. These results indicated that peeled garlic could be stored at $-18^{\circ}C$ for longer than 15 months without quality problems.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.182-187
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• 2003

Quality attributes of reconstructed pork patties with ISP were evaluated. Reconstructed pork patties with 30% meat plus ISP and 50% meat plus had significantly less cooking loss and dimensional changes than control. Sensory evaluation revealed patties with 30 or 50% meat had higher hardness and juiciness than control, patties with ISP, and patties with direct addition of ISP. Objective elasticities of patties with 30 or 50 % meat were high, whereas patties without ISP had higher values of hardness, gumminess, and chewiness. Color of patties with 30 or 50% meat were different from that of control. These result show addition of ISP to meat emulsion for pork patties markedly improved cooking loss, dimensional changes, hardness, and juiciness. When pork patties and cutlets prepared according to meat (30%) formula were frozen, cooking loss was significantly higher in slow-frozen patties, but freezing rate did not affect dimensional changes of patties and cutlets. Slow-frozen patties had higher hardness, but other textural properties were affected by the freezing rate. Quality of pork cutlets was not significantly changed by the freezing rate.