• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.101-105
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• 2008

Enterobacter sakazakii is implicated in severe forms of neonatal infections such as meningitis and sepsis. This organism has been isolated from a wide range of foods, including cheese, vegetables, grains, herbs, and spices, but its primary environment is still unknown. Generally, dried infant milk formula has been epidemiologically identified as the source of E. sakazakii. Sunsik (a powdered mixture of roasted grains and other foodstuffs) is widely consumed in Korea as a side dish or energy supplement. Sunsik is consumed without heat treatment; thus, lacking an additional opportunity to inactivate foodborne pathogens. Therefore, its microbiological safety should be guaranteed. In this study, the prevalence of E. sakazakii was monitored in 23 different sunsik component flours, using FDA recommended methods; but E. sakazakii medium (Neogen) and Chromogenic E. sakazakii medium (Oxoid) were used as the selective media. In total, presumptive E. sakazakii strains were isolated from 8 different sunsik powders. Subsequently, an API 20E test was conducted, and 15 strains from 5 different sunsik flours (sea tangle, brown rice, non-glutinous rice, cheonggukjang, dried anchovy) were confirmed as E. sakazakii. Fifteen strains were again confirmed by PCR amplification, using three different primer sets (tDNA sequence, ITS sequence, 16S rRNA sequence), and compared to ATCC strains (12868, 29004, 29544, 51329). They were once again confirmed by their enzyme production profiles using an API ZYM kit. Finally, RAPD (random amplified polymorphic DNA)-genotyping was carried out as a monitoring tool to determine the contamination route of E. sakazakii during processing.

• Journal of Food Hygiene and Safety
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• v.25 no.4
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• pp.376-387
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• 2010

Recently, speedy, convenient and easy detection technologies have been developed rapidly and on the contrary, studies on development of traditional detectors applying biochemical characteristics has gradually been decreased. This review examined trend in current studies on detection of food-borne pathogenic microorganisms in the fields of selective media, immuno-assay, Polymerase Chain Reaction (PCR), microarray, terahertz spectroscopy & imagination and so on. Most traditional methods to detect the organisms from food matrix rely on selective media and such a method have disadvantages like long time requirement and distinguishing one species only from each selective medium although they are highly economical. Various new convenient methods such as Enzyme Linked Immuno-sorbent Assay (ELISA), paper-strip kit, fluoroimmunoassay etc. have been developed. The most ideal method for detecting food-borne pathogenic microorganisms in foods should be accurate, convenient, rapid and economical. Additionally, it is needed that capabilities of quantitative analysis and automation to be applied to industries.

• Journal of Food Hygiene and Safety
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• v.33 no.3
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• pp.193-199
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• 2018

In this study, PAT protein of genetically modified maize was prepared from the recombinant E. coli strain BL21 (DE3), and mice were immunized with the recombinant PAT protein. After cell fusion and cloning, two hybridoma cells (PATmAb-7 and PATmAb-12) were chosen since the monoclonal antibodies (Mabs) produced by them were confirmed to be specific to PAT protein in the indirect enzyme-linked immunsorbent assay (ELISA) and western blot tests. There were no cross-reactions of either Mabs to other GM proteins or to the extracts of non-GM maize. The ELISA based on the PATmAb-7 can sensitively detect 0.3 ng/g PAT protein in corn. These results indicate that the developed Mabs can be used as bio-receptors in the development of immunosensors and biosensors for the rapid and simple detection of GM corn adulterated in foods.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.891-896
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• 1995

In order to screen natural inhibitor of tyrosinase which catalyzes an enzymatic browning of some foods and in vivo synthesis of melanin, inhibitory effect of 129 edible plants and 15 chemical compounds on the in vivo melanin synthesis by mushroom tyrosinase was analyzed. Among leafy vegetables tested, radish bud, red chicory, Shepherd's purse and small green onion were found to have more than 50% tyrosinase inhibition effect in the descending order. Chinese radish and garlic in root vegetables, and nameko, shiitake and oyster mushroom in mushrooms, and teas showed also more than 50% inhibition effect. Among fruit vegetables tested, red pepper, Chinese quince and avocado were found to have more than 50% tyrosinase inhibition effect, while fruits generally showed low inhibitory effect. Medicinal plants which inhibit tyrosinase more than 50% were mume fructus>cinamomi ramulus>rubi fructus>mori cortex>biotae orientalis folium>puerariae radix, and herbs with more than 50% inhibitory effect were allspice>clove>mustard. In some chemical compounds tested, 4-hexylresorcinol, L-cysteine, glutathione, sodium bisulfite and kojic acid showed powerful inhibition effect on mushroom tyrosinase.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.417-422
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• 2003

The onions are considered to be a favorable functional source of beverage because they contain much sugar and various nutrients, and they are juicy vegetable. Recently, consumers have a new trend to take functional foods with health benefits. To meet this need, this study was the basic research to establish a manufacturing process of functional onion beverage by glucose oxidase. Glucose oxidase catalyzes reaction of glucose oxidation and makes generation of gluconic acid. Kinetics of the reaction was also investigated, and maximum glucose consumption rate $(V_{max})$ of $26.1{\times}10^{-2}\;g/L{\cdot}min$ and $K_m$ of 5.84 g/L were obtained. Optimum conditions were obtained when the glucose oxidase catalyzed reaction was carried out at temperature of $25^{\circ}C$, agitation rate of 450 rpm and aeration rate of 4 vvm in a 2.5 L jar fermentor. Finally, the enzyme reactor was 10-times scaled up and a similar glucose oxidation performance was achieved in the scaled-up reactor.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.696-701
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• 2003

Rice seeds of 4 cultivars including Whachung and Nampung, of the non-waxy rice cultivars, and Shinsunchalbyeo and Whachungchabyeo, of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physico-chemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy rices, while the chain length increased in the waxy rices. In the distribution profile of the glucose chain length from amylose molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 increased with the decreasing rate of the chain length with that above 130, regardless of the waxiness of rices. In addition, we observed that in contrast to a increase in chain length with DP ranged 14 to 33, the amount of short chains from A chain fraction decreased. Germination induced slight reduction in the polymerization rate of starch granules, and decrease in both initiation and termination temperatures for the gelatinization. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to he higher than that of malt. Especially, the activity of Shinsunchalbyeo was revealed to be highest, about two fold higher than that of malt. In contrast, ${\beta}-amylase$ of the waxy rice found to be considerably less active than malt, although the waxy showed prevalent activity as compared to the non-waxy rices.

• Microbiology and Biotechnology Letters
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• v.42 no.1
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• pp.11-17
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• 2014

Selenium is an essential trace element for mammals, but it is very toxic. Therefore, the control of selenium concentrations should be precisely and effectively monitored. Selenium is naturally obtained through foods and seleno-L-methionine (LSeMet) is a major form of selenium. It has been reported that L-SeMet is only converted into Se-adenosyl-L-SeMet. However, a recent study suggested that L-SeMet was directly metabolized into methylselenol ($CH_3SeH$) in mouse liver extract by the reaction of cystathionine ${\gamma}$-lyase (CGL). The canonical reaction of CGL was known to catalyze the cleavage of L-cystathionine to L-cysteine, ${\alpha}$-ketobutyrate and $NH_3$. In the present study, we found that L-SeMet could be directly converted to $CH_3SeH$ using purified homogenous human CGL instead of mouse liver cytosol. Authentic $CH_3SeH$ was prepared by reduction of dimethyldiselenide with sodium tetrahydroborate. The gaseous product of the enzymatic reaction with L-SeMet was analyzed by GC/MS spectrometry. The GC/MS data was identical to that of authentic dinitrophenyl selenoether. We also analyzed the kinetic parameters for the formation of $CH_3SeH$ from L-SeMet by human and mouse CGL. These results suggest that human CGL is a critical enzyme which is responsible for L-SeMet metabolism.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1134-1139
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• 2002

Campylobacter, Arcobacter, and Helicobacter, classified into the same rRNA superfamily VI by taxonomy, cause food-borne diseases, stomach ulcer, and gastric cancer. To detect each strain selectively from contaminated foods, PCR, multiplex-PCR, and restricion fragment length polymorphism (RFLP) were applied on Campylobacter, Arcobacter, and Helicobacter. The same PCR products could be detected using CHA primer targeted for 16S rRNA of Campylobacter, Arcobacter, and Helicobacter. To detect C. jejuni and C. coli from A. butzleri and H. pylori, pg50/pg3 primer targeted for fla A gene was used, and for A. butzleri, Arco2/Butz primer targeted for 23S rRNA was utilized. For H. pylori detection, icd1/icd2 primer targeted for isocitrate dehydrogenase gene was employed, and JEJ1/JEJ2 primer targeted for ceuE gene was effective for C. jejuni detection from the three strains. C. jejuni, C. coli could be separated from A. butzleri and H. pylori through PCR-RFLP using restriction enzyme Dde I. Such primers would be effective for detecting each strain selectively through PCR when C. jejuni, C. coli, A butzleri and H. pylori are contaminated together.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.535-543
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• 2021

Particulate matter (PM) causes oxidative stress and can rapidly diffuse from the lung to the blood and accumulate in the liver when inhaled. Natural antioxidants can be used to protect against oxidative stress caused by PM. Sargassum horneri, a brown seaweed, possesses antioxidative activity and is a good source of functional foods. Therefore, this study investigated the antioxidant potential of S. horneri extract (SHE) in the livers of PM-induced asthmatic mice. PM inhalation triggered lipid peroxidation and oxidative stress, and SHE treatment attenuated malondialdehyde in the liver of mice with PM-induced asthma. Furthermore, SHE mitigated the increase in catalase activity. Importantly, SHE reduced the activity of 8-oxoguanine glycosylase (OGG1), a DNA repair enzyme. These results suggest that SHE has antioxidant potential for moderating PM-induced oxidative stress and DNA damage in the liver of asthmatic mice.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.479-486
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• 2019

This study investigated the anti-inflammatory effects of mixed extracts of Achyranthes japonica Nakai (Aj) and Aralia continentalis Kitagawa (Ac) (ratios of 1 : 2, 1 : 3, 1 : 5, 2 : 1, 3 : 1 and 5 : 1) on RAW264.7 macrophages. Cell toxicity was determined using a cell counting kit (CCK) assay. We evaluated anti-inflammatory effects of the mixed extracts of Aj and Ac by measuring interleukin $(IL)-1{\beta}$, IL-6, and tumor necrosis factor $(TNF){\alpha}$ using an enzyme-linked immunosorbent assay (ELISA) kit assay. The mixed extracts of Aj and Ac inhibited lipopolysaccharide (LPS)-induced $IL-1{\beta}$ and $TNF{\alpha}$ in LPS-stimulated macrophages. Comparing different ratios of the mixed extracts, the 2 : 1 ratio of Aj and Ac has much more potency and inhibited the production of $TNF{\alpha}$ in LPS-induced RAW264.7 cells. The results of the present study showed that the mixed extracts of Aj and Ac have potential anti-inflammatory effects on RAW264.7 macrophages. Therefore, these extracts may be used as a good source of functional foods for the protection against inflammatory diseases.