Earticle

The purpose of this study was to develop a methodology to detect spinosad which are difficult to analyze by multi-component simultaneous analysis of pesticide residues. We monitored spinosad due to the paucity of related information. The spinosad was determined using HPLC with UV detector at 250 nm. Correlation coefficient (r2) for standard curve of spinosad A and D at standard concentration of 0.1-5.0 mg/kg were 0.999, respectively. Limit of quantitation (LOQ) of HPLC analysis was 0.005 mg/kg while limit of detection (LOD) was 0.001 mg/kg. Recovery experiments were conducted on five representative agricultural products to validate the analytical method. The recovery of proposed methods ranged from 74.9% to 104.0% and relative standard deviations were less than 10%. Spinosad residues were investigated in 16 commodities collected from 22 provinces. In this study, residues on all samples were not detected.

Two-hundred Bacillus cereus isolated from perilla leaf cultivation areas in Miryang, Korea were investigated for toxin genes and antibiotic susceptibility. Toxigenic patterns of isolates were identified to be 11 groups through toxin gene profiles. 21% of strains isolated from the perilla leaves had both enterotoxin and emetic toxin. Toxin genes entFM (100%), nheA (100%) and hblA, C, D (65.5%) were frequently found in the perilla leaves, whereas EM (21.0%) was less common. Most isolates were susceptible to 10 antibiotics, but they were highly resistant to penicillin (100%), ampicillin (100%), oxacillin (94.9%), amoxicillin-clavulanic acid (95.6%), cefazolin (78.2%), and rifampicin (58.0%). These results indicate that food-borne outbreak caused by B. cereus might lead to diarrhea and emetic syndromes.

The objective of this study was to analyze proximate composition and physicochemical properties according to different kinds of rice. In total, 20 varieties of rice were used (Domestic-19, Imported-1). The moisture contents ranged from 11.11±0.20 to 3.28±0.03%. The crude protein and crude lipid contents were ranged from 5.04±0.03 to 7.02±0.10% and 0.18±0.01 to 0.73±0.05%, respectively. The mineral contents were Calcium, 3.56±0.11-6.69±0.08 mg/100 g; Sodium, 3.39±0.01-17.43±0.04 mg/100 g; Phosphorus, 64.12±0.88-102.0±0.36 mg/100 g; Zinc, 0.95±0.01-1.75±0.0 mg/100 g; Iron, 0.19±0.0-0.69±0.02 mg/100 g; Magnesium, 9.89±0.47-23.310.21 mg/100 g; Potassium, 47.11±3.49-82.19±1.08 mg/100 g; and Manganese, 0.47±0.0-1.14±0.01 mg/100 g. Eighteen kinds of rice exhibited small kernels. Amylose contents ranged from 10.3±1.27 to 19.4±0.15%, while starch value ranged from 70.8±2.67 to 80.1±5.09%. Alkali digestion value was described as 5-6 grade and gel consistency was shown to be ‘soft’ regardless of the rice kinds.

This study was carried out to develop a method of removing unnecessary sugars and high-molecular weight soluble components from water extract by using various highly porous polymer resins: these resins are widely used as adsorbents for polyphenolic compounds. Each anthocyanin-rich fraction (ARF) that was eluted from column packed with 4 different resins (SEPABEADS SP207, 700, 850 and Diaion HP 20) was obtained from an aqueous extract of the ripe fruits of Rubus coreanus, which is well-known in Korea as “Bok-bun-ja”. Among the above mentioned resins, Diaion HP20 had the highest efficacy and provided maximum yield of the ARF. The ARF eluted from the column packed with HP 20 exhibited the strongest antioxidant activity in vitro. Bioactive phytochemicals extracted from Rubus coreanus were investigated using the on-line HPLC-ABTS•+ system, and the resulting 6 peaks were identified as radical-scavenging components. By using liquid chromatography-mass spectrometry, 5 peaks were obtained, and these were identified as cyanidin-3-sambubioside, cyanidin-3-glucoside, cyanidin-3-xylosylrutinoside, cyanidin-3-rutinoside and pelargonidin-3-rutinoside. These results indicate that the use of appropriate porous resin (Diaion HP 20) leads to an increase in the yield of bioactive components and enhancement of their biological properties.

A tray type-infrared (IR) pasteurization system was developed for decreasing microorganisms in red pepper powder (RPP). The RPP was passed through a tray by a vibrating mode under the 4 IR lamps (total 8000 W) and by circulating water under the tray. Fungi was pasteurized by applying power higher than 2000 W to the RPP. The decrease in viable cell numbers of bacteria, however, was not observed under the same conditions. Conveying speed of RPP was optimized to 106-164 g/min on the basis of microbial reduction and retaining of moisture content of RPP. The water content of 32 mesh-RPP decreased rapidly after pasteurization. However, fungi in both RPPs could be sterilized regardless of particle sizes. The repetition of IR pasteurization was not favourable due to severe decrease of water content in RPP. The IR pasteurization of RPP did not cause significant difference in the capsaicinoid contents, ASTA colour value, and L, a, and b values under all investigated conditions.

The purpose of this study was to evaluate microbiological contamination of fresh vegetables in Korea. Twenty types of vegetables were tested for total aerobic bacteria, coliforms, Escherichia coli, yeast and mold, and pathogenic bacteria such as Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Salmonella, E. coli O157:H7, Cronobacter sakazakii, Shigella, and Campylobacter. Levels of total aerobic bacteria and coliform on 20 vegetables were between 3.74 and 8.04 log CFU/g, and 0.16 and 5.02 log CFU/g, respectively. The highest contamination levels of total aerobic bacteria were observed on water dropwort, sprouts, mungbean sprout, and ballflower root. There was no significant difference (p>0.05) in microbial contamination levels of total aerobic count, coliform, E. coli, yeast and mold between organic and nonorganic vegetables. When isolation methods using selective agars were applied, L. monocytogenes, B. cereus, Salmonella and Campylobacter were isolated from some fresh vegetable samples. Results of API kit tests showed that L. monocytogenes was identified on Chinese cabbage, cucumber, soybean sprouts, and iceberg lettuce while Salmonella was identified on Korean leek. Furthermore, Campylobacter jejuni was also identified in more than 50 of the 100 samples. However, when positive samples from API kit were tested for real-time PCR or 16S rRNA sequencing method, only B. cereus from perilla leaf, carrot, water dropwort, and sprouts showed positive results. These results indicate that selective agar and API kit detection methods might result in false positive results for some pathogens. Therefore, studies need to improve isolation or confirmation methods for such pathogens.

The β-xylosidase (EC 3.2.1.37) production capabilities of lactic acid bacteria in the genus Leuconostoc, isolated from a variety of kimchi (fermented vegetables), were examined. The intracellular levels of β-xylosidase were similar to the extracellular levels, when most Leuconostoc lactic acid bacteria were grown in a medium containing xylose as the carbon source. Intracellular β-xylosidase with a maximum activity of 1.2±0.1 units/mL (mean±standard error) was obtained from Leuconostoc lactis KCTC 13344, which was isolated from fermented Chinese cabbage. The optimum reaction conditions for Leu. lactis KCTC 13344 β-xylosidase activity were pH 6.0 and 30oC, and the addition of most divalent cations, except zinc, to the reaction mixture resulted in a slight increase in enzyme activity. Compared with a media containing other carbon sources, the β-xylosidase activity was 5 times higher when Leu. lactis KCTC 13344 was grown in a medium containing xylose as carbon source. Zymographic analysis indicated that the synthesis of Leu. lactis KCTC 13344 β-xylosidase (approximate size, 64 kDa) is induced by xylose. A maximum intracellular β-xylosidase activity of 7.1±0.3 units/mL was obtained in a batch cultivation in an MRS medium containing 30 g/L xylose.

Cronobacter sakazakii and Salmonella enterica Typhimurium are hazardous pathogens, especially for ready-toeat foods. For control of pathogens, the virulent bacteriophages were isolated, identified, and applied to infant formula milk and vegetable juice. The phages were isolated from swine feces and identified by morphology and molecular characteristics. ES2 phage for C. sakazakii and ST2 phage for S enterica Typhimurium were identified as Myoviridae and Siphoviridae, respectively. Their burst sizes were 52±5 PFU/cell for ES2 phage and 21±3 PFU/cell for ST2 phage after latent period of 30-40 minutes. ST2 phage showed higher heat stability at 60oC than ES2 phage. ES2 phage held the growth of C. sakazakii untill 6 hr afterwhich the number decreased when applied to the infant formula milk and vegetable juice. ST2 phage also showed growth inhibition so that the number of S. enterica Typhimurium decreased. Therefore, virulent bacteriophages might be an agent for the growth inhibition of C. sakazakii and S. enterica Typhimurium in such the ready-to-eat foods.

Excess sugar intake by food consumption may contribute to the development of diabetes, dental caries, attention deficit hyperactivity disorder (ADHD), and cardiovascular disease. The objective of this study was to investigate the sugar intake from meals at nursery schools in Gyeonggi-Do, and to construct a database for reduction policies sugar intake. A total of 601 samples were analyzed for sugar intake in summer and winter, respectively. The average sugar intake from food service was 2.22 g/meal, which was 5% of the Recommended Daily Intake (RDI). Furthermore, the analysis results of sugar content were in the decreasing order of fruits (5.05 g/100 g), fried food (2.92 g/100 g), and braised food (2.31 g/ 100 g). The habit of excessive sugar intake in childhood can be threaten health in adulthood. Thus, it is necessary for nursery school children to consume schoolmeals that contain less sugar.

Effect of Sargassum confusum extract on the reduction of body weight gain and lipid contents in obese rats were evaluated to find natural materials with anti-obesity benefits. After inducing obesity by feeding 42.5% high-fat diet for 5 weeks, each 10 Sprague-Dawley rats were randomly assigned to high-fat diet control (HFD) group and high-fat diet group containing 3% Sargassum confusum extract (HFDSC). Weight gain of HFD group (2.96±0.31 g/day) was significantly (p<0.05) higher as compared to that of normal diet (ND) group (2.19±0.17 g/day). Weights of adipose tissues of HFD group were higher than those of ND group. Body weight gain of HFDSC group, however, was 2.36±0.24 g/day, which was significantly (p<0.05) lower by 21% than that of HFD group. In addition, weights of epididymal and perirenal adipose tissues were lower by 15% and 16%, respectively, as compared to those of HFD group. Biochemical analyses showed that concentration of triglyceride, total cholesterol, and fatty acids were significantly (p<0.05) lower in HFDSC group. These results suggest that Sargassum confusum extract has a high potential as an anti-obesity material by reducing weight gain and obesity-related factors in serum.

This study investigated the antioxidant effects and physiological activities of extract from various parts of pumpkin (Cucurbita moschata Duch.) such as leaf, flesh, skin and seed. Different dried parts of C. moschata were boiled in ethanol for three hours, evaporated, and lyophilized with a freeze-dryer. Total polyphenol contents were the highest in leaf (29.62±0.88 mg GAE/g DM). The same result was observed in the measurement of the flavonoid content. The leaf extract of C. moschata had stronger DPPH radical-scavenging activities and ABTS-radical scavenging activities than any other part. Leaf extract of C. moschata was found to have the highest ferric-reducing antioxidant power (FRAP) value. Meanwhile, at 0.1 mg/mL of all extracts higher degree of tyrosinase inhibitory effects than kojic acid was observed (leaf; 49.58%, flesh; 40.20%, skin; 41.30%, seed; 36.79% and kojic acid; 20.70%). The glycation inhibitory activity decreased in the order leaf>skin>flesh>seed. The α-glucosidase inhibitory activity of seed extract was the highest with a value of 63.58% at the concentration of 1 mg/mL.

In this study, antioxidant and anti-inflammatory effects of ethanol extracts from medicinal herb mixtures were investigated in vitro. Contents of total polyphenols in ethanol extracts from Houttuynia cordata Thunb. (HC), Carthamus tinctorius L. (CT), and MIX-2 (Houttuynia cordata Thunb., Acanthopanax gracilistylus Smith, Carthamus tinctorius L., Kalopanax pictus) were 58.98, 60.79 and 57.74 mg/g respectively. Radical scavenging activities of the ethanol extracts were examined using α,α-diphenyl-β-picrylhydrazyl radicals and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assay. Anti-inflammatory effects of ethanol extracts from medicinal herbs composites were examined using 5-lipoxygenase (5- LO), cyclooxygenase-2 (COX-2) and nitric oxide (NO) inhibition assays. The ethanol extracts from medicinal herb mixtures showed higher 5-LO and COX-2 inhibition activities than those from single medicinal herbs. The ethanol extracts from medicinal herb mixtures also showed strong anti-inflammatory activity through inhibition of NO production.

Makgeolli is Korean traditional alcoholic beverage that has historically been brewed. In this study, we analyzed the profile of organic acids in makgeolli and also evaluated its physiological characteristics. Makgeolli contained excess lactic acid, which is produced by lactic acid bacteria (LAB). Anti-obesity effects of makgeolli were investigated in 3T3- L1 preadipocytes. Compared to the negative control, makgeolli inhibited the differentiation of preadipocyte as quantified by Oil red O dye. In particular, 100 μg/mL makgeolli reduced 40 to 70% of differentiation. To evaluate the anti-angiogenic and anti-inflammatory effects of makgeolli, we performed chorioallantoic membrane assay and measured nitric oxide production from lipopolysaccharide-induced RAW264.7 cells. Most makgeolli interrupted the formation of neo-vasculature and significantly inhibited NO production in a dose-dependent manner. Taken together, these findings suggest that commercial makgeolli has inhibitory activities against adipogenesis, neo-vascularization, and inflammation, and also they are influenced by second metabolites from nuruk microflora containing fungi and LAB.

The metastatic effect of Eupatorium japonicum extract (EJE) on MDA-MB-231 human breast cancer cells was investigated. MDA-MB-231 cells were treated with various concentrations of EJE (0, 5, 10 and 20 μg/mL). EJE inhibited cell migration, invasion and adhesion of MDA-MB-231 cells in dose-dependent manners. Gelatin zymography exhibited that EJE significantly down regulated secretion of matrix metalloproteinase (MMP)-9 and MMP-2. EJE decreased the protein levels of tissue inhibitor of metalloproteinase (TIMP)-1 but increased TIMP-2 levels. Additionally, EJE reduced the protein and mRNA levels of urokinase-type plasminogen activator (uPA), vascular endothelial growth factor (VEGF) and intercellular adhesion molecule (ICAM). In several solvent fractions of EJE, the hexane fraction markedly decreased MDAMB- 231 cell migration. Thus, these finding suggest that EJE may be a potential antimetastatic agent, which can considerably inhibit the metastatic and invasive capacity of breast cancer cells.

Human basophilic KU812F cells express a high affinity for IgE receptor, FcεRI, which plays an important role in immunoglobulin E (IgE)-mediated allergic reactions. Using the human basophilic KU812F cells, we assessed the inhibitory effects of the ethanolic extract from Chrysanthemum zawadsaki(CZ) on FcεRI α chain expression. Flow cytometric analysis showed that cell surface FcεRI α chain expression was suppressed when the cells were cultured with CZ extract. RT-PCR analysis showed that the mRNAs for FcεRI α chain decreased by the treatment of CZ extract. Moreover, CZ extract was also observed to result in a reduction in the release of histamine from anti-FcεRI antibody (CRA-1)-stimulated cells. These results suggest that CZ extract may exert anti-allergic activity through down-regulation of FcεRI α chain expression and a subsequent decrease in histamine release.

Zearalenone (ZEA) is an estrogenic mycotoxin mainly produced by Fusarium graminerum, a species which colonizes a wide variety of cereals, including wheat, barley and processed products. A survey of ZEA contamination was conducted on 141 dried confectioneries, 59 breads and rice cakes, 135 noodles and 101 other products, for a total of 432 commercial samples. Samples were analyzed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) after immunoaffinity clean-up and was confirmed by liquid chromatography tandem mass spectrometry (LCMS/ MS). The limits of detection and quantification were 2.0 and 6.0 μg/kg, respectively. The recovery ranged from 80.2% to 98.4% in the cereal based product. ZEA was detected in 38 samples (8.8% incidence), including 3 snack, 2 biscuit and 33 other cereal products. The ZEA contamination levels were in the range of 5.38-53.76 μg/kg. Finally, LC-MS/MS analysis of the contaminated samples was conducted to confirm the detected ZEA, and all 38 samples showing ZEA by HPLC-FLD were confirmed by LC-MS/MS.

According to the Codex committee, the maximum allowable level for lead in fruits is 0.1 mg/kg. This survey was conducted as a surveillance program following the establishment of safety guideline for fruits in Korea. Concentrations of lead (Pb), cadmium (Cd), arsenic (As) and mercury (Hg) were measured in 927 samples using a ICP-MS and a mercury analyzer. The recoveries of microwave digestion method were 86.0-110.4% for Pb, 81.0-104.0% for Cd and 82.0- 104.7% for As by standard addition method. The recovery of direct mercury analyzer was 106.5% for Hg. The average levels of Pb in μg/kg were 10.0±12.8 for apple, 8.8±10.9 for pear, 4.1±4.4 for persimmons, 14.9±12.3 for mandarin, 7.1±6.5 for orange, 3.1±3.3 for banana, 8.8±8.9 for kiwi, and 9.3±9.7 for mango. The average levels of Cd in μg/kg were 0.4±0.3 for apple, 2.0±1.6 for pear, 0.3±0.3 for persimmon, 0.1±0.1 for mandarin, 0.1±0.1 for orange, 1.3±1.8 for banana, 0.5±0.5 for kiwi, and 0.7±0.6 for mango. The average levels of As in μg/kg were 2.0±2.1 for apple, 1.2±1.3 for pear, 1.5±1.1 for persimmon, 0.8±0.3 for mandarin, 1.0±0.5 for orange, 1.8±1.2 for banana, 1.6±1.5 for kiwi, and 1.5±1.2 for mango. The average levels of Hg in μg/kg were 0.5±0.4 for apple, 0.3±0.2 for pear, 0.2±0.1 for persimmon, 0.2±0.1 for mandarin, 0.2±0.1 for orange, 0.2±0.0 for banana, 0.2±0.2 for kiwi, and 0.6±0.2 for mango. Based on the Korean public nutrition report 2005, these levels (or amounts) are calculated only at 0.17% for Pb, 0.013% for Cd and 0.006% for Hg of those presented in provisional tolerable weekly Intake (PTWI) which has been established by FAO/WHO. Therefore, the levels presented here are presumed to be adequately safe.

Liquid-state fermentation of Monascus koji was performed using 10% honey as the nutrient source. The rheological characteristics of flour doughs with added red koji broth were evaluated and revealed the following results. The falling number which represents the paste characteristics decreased, as the amount of added red koji broth increased. Adding 10% broth resulted in a falling number of 363±7.8 s and with 20% it was 318±2.1 s. In the measurement of gelatinization using a rapid visco analyzer, increasing the red koji broth decreased peak viscosity, peak viscosity time, holding strength, final viscosity and set-back values, but initial pasting temperature and breakdown value increased. In the farinograph measurements, no significantly different absorption was found between the control and the treatments, and the results were 64.3-65.0%. The consistency and tolerance index of the doughs were higher in the treatments than the control. Increasing the broth addition ratio increased the measurement values, however development time and time to break down the doughs decreased. Stability also decreased and adding 20% broth resulted in a 9.3 min development time, and adding 40% broth resulted in a 3.0 min development time. In the alveographic analysis, the P max (overpressure) value of the control was 158.0 mm. P max value increased to 190.0 mm after adding 40% broth. However the values of L, G and W were higher in the control. As a result, little influence on dough rheology was observed by adding red koji broth 20%.

In this study, liquid culture of Tricholoma matsutake mycelia was performed via biomass production, and its inhibitory effects on melanin biosynthesis were evaluated. The Tricholoma matsutake mycelia extract inhibited 38.6% of tyrosinase activity at 100 ppm, which is higher than that of extracelluar medium at same dose. In addition, when 100 ppm of Tricholoma matsutake mycelia extract was treated to melan-a cells for 3 days, 19% of melanin production was reduced without cell toxicity. These results suggested that cultured Tricholoma matsutake mycelia might be useful as a skin depigmenting material.

The prevalence and distribution of hazardous microorganisms were investigated from the major perilla cultivation area at Milyang, Gyeongnam province, Korea. Aerobic plate count (APC) and coliform count of perilla leaves were 4.82 log CFU/g and 3.85 log CFU/g, respectively. E. coli, S. aureus and B. cereus were detected in 3.0% (4/114), 7.9% (9/114) and 46.5% (53/114) of examined perilla leaves. However, E. coli O157:H7, Salmonella spp, and L. monocytogenes were not detected. The distribution of hazardous microorganisms in perilla leaf cultivation environment were compared and the concentration of APC and coliform counts were more than 3.0 log CFU/(mL, g, 100 cm2, hand) from most of the samples. S. aureus were detected from irrigation water, packing table, packing vinyl, hand, and clothes. Also, B. cereus was frequently detected from the examined samples. Especially, packing table and collection container were contaminated with maximum 5.5 log CFU/100 cm2 of B. cereus. Good Agricultural Practice (GAP) system should be introduced to farms to enhance the safety of perilla leaves.