• Title/Summary/Keyword: the leafy vegetables

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Elution Buffers for Human Enteric Viruses in Vegetables with Applications to Norovirus Detection

  • Moon, Aerie;Ahn, Jaehyun;Choi, Weon Sang
    • Journal of Food Hygiene and Safety
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    • v.28 no.4
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    • pp.287-292
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    • 2013
  • The efficient elution of viruses from contaminated food is a critical step for its detection. In this study, conditions optimal for enteric viral recovery from three leafy vegetables (cabbage, lettuce, sesame leaf) and three root vegetables (carrot, onion, mooli) were analyzed to find common buffers (statistically not different) applicable to the leafy and root vegetables. Viral recovery varied depending on the food matrices or elution buffers. Buffer solutions containing 0.25M threonine / 0.3M NaCl (pH 9.5) or 0.25M glycine / 0.14M NaCl (pH 9.5) could efficiently recover poliovirus from five out of six vegetables. The threonine buffer was applied to one leafy vegetable (sesame) and one root vegetable (carrot) for genogroup II norovirus (NoV) detection. The detection sensitivity was significantly higher from the leafy vegetable compared to the root vegetable. The use of these common elution buffers should facilitate the detection of low levels of NoV and other enteric viruses in a wide range of vegetables.

Antioxidant Activity of Salad Vegetables Grown in Korea

  • Xin Zao;Song, Kyung-Bin;Kim, Mee-Ree
    • Preventive Nutrition and Food Science
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    • v.9 no.4
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    • pp.289-294
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    • 2004
  • The antioxidant activity of forty two kinds of salad vegetables grown in Korea was evaluated. Methanol extract of freeze-dried vegetable was assayed by radical scavenging activity using 1,2-diphenyl-2-picrylhydrazyl (DPPH) and Fe^{2+}$-catalyzed lipid peroxidation inhibition by TBA method. Total phenolics were determined colorimetrically using Folin-Ciocalteu reagent. The highest radical scavenging activity was expressed by perilla leaf, followed by dandelion leaf, red and green leafy lettuce, of which $IC_{50}$ was less than 0.10 mg/mL. Angelica leaf showed the highest inhibitory action for lipid peroxidation with $95\%$, and then dandelion leaf, water spinach, and perilla leaf inhibited over $80\%$. However, lettuce (Iceberg) and young Chinese cabbage exhibited the lowest antioxidant activity based on both assay methods. Highly positive correlations between antioxidative activities and total phenolics were observed (p < 0.001). The results suggested that salad vegetables, especially perilla leaf, leafy lettuce, dandelion or angelica, could be used for easily accessible sources of natural antioxidants.

Effects of Crude Protein Levels in Diets Containing MKP on Water Quality and the Growth of Japanese Eels Anguilla japonica and Leafy Vegetables in a Hybrid BFT-Aquaponic System (일인산칼륨(MKP)이 함유된 사료 내 단백질 수준이 Hybrid BFT 아쿠아포닉스(HBFT-AP)의 뱀장어(Anguilla japonica) 및 엽채류의 생산성과 수질변화에 미치는 영향)

  • Lee, Dong-Hoon;Kim, Jin-Young;Lim, Seong-Ryul;Kim, Kwang-Bae;Kim, Joo-Min;Hariati, Anik M.;Kim, Dong-Woo;Kim, Jeong-Dae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.53 no.4
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    • pp.606-619
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    • 2020
  • This study investigated the effects of crude protein levels in diets containing monobasic potassium phosphate (MKP) on water quality and the growth of Japanese eels Anguilla japonica and leafy vegetables in a Hybrid BFT-Aquaponics (HBFT-AP) system. The first experiment (EXP1) was designed to verify the effects of the feed itself on leafy vegetable productivity using two diets (CP48 and CP30) with MKP and one commercial eel diet (COM58). The second experiment (EXP2) examined the effects of the three diets on productivity of the fish and leafy vegetables in the HBFT-AP for 6 weeks. After the 6 week feeding trial, the weight gain, feed efficiency, specific growth rate and protein efficiency ratio of fish fed COM58 and CP48 were higher than those of fish fed CP30 (P<0.05) and the growth of the four leafy vegetables was the highest with fish fed CP48. Water quality was measured six times per week using a portable water quality meter and reagent measurements and showed variance with time for TAN (0.01-0.09 mg/L), NO2-N (0.010-0.064 mg/L), NO3-N (5.52-27.15 mg/L), PO4-P (2.03-5.32 mg/L) and pH (7.86-6.15).

Effect of Circulation Cycle of Nutrient Solution on the Dissolved Oxygen Concentration, and the Growth and Phytonutrient Contents of Leafy Vegetables Grown in DFT Systems (양액의 순환주기가 담액수경 엽채류의 용존산소 농도, 생육 및 식물영양소의 함량에 미치는 영향)

  • Seo, Tae-Cheol;Rhee, Han-Cheol;Rho, Mi-Young;Choi, Kyeong-Lee;Yun, Hyung-Kwon;Chun, Chang-Hoo
    • Journal of Bio-Environment Control
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    • v.18 no.2
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    • pp.112-118
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    • 2009
  • To determine the effects of circulation frequency of nutrient solution, three frequencies of 10min. on/10min. off; 10min. on/110min. off; and 10min. on/1,430min. off. treatments were applied to leafy vegetable production using deep flow technique (DFT) systems and their growth and phytonutrient content were investigated. In the 10min. on/I,430min. off treatment, dissolved oxygen concentration (DOC) 17 days after treatment decreased to 2.8mg. $L^{-1}$, known to be a low DOC that causes hypoxia, and thereafter decreased to 1.5mg. $L^{-1}$ 20 days after treatment. Fresh weight of 7 leafy vegetables in the 10min. on/1,430min. off treatment was lower by 0${\sim}$24% than those in the 10min. on/110min. off treatment, and those in the 10min. on/10min. off was higher by -2${\sim}$34% than those in the 10min. on/110min. off treatment as control. As the more frequent circulation was applied, the higher phosphorous content and the lower carbon to nitrogen ratio (C/N ratio) and total ascorbic acid contents were resulted. Results indicate that the circulation frequency of 110min, on/110min. off could be recommended for the production of the tested leafy vegetables in DFT systems.

Comparative study on growth of leafy vegetables grown in a hybrid BFT-aquaponics using Japanese eel, Anguilla japonica and hydroponics

  • Lee, Dong-Hoon;Kim, Jeong-Dae
    • Fisheries and Aquatic Sciences
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    • v.24 no.7
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    • pp.260-275
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    • 2021
  • Aquaponics is a cultivation system that combines aquaculture and agricultural hydroponics. This study investigated the productivity of leafy vegetables cultivated in the hybrid biofloc technology-aquaponics (HBFT-AP) using Japanese eel fed two kinds of diets (Mash, commercial powdered feed and extruded pellet [EP]) and hydroponics (HP).The mash was fed to the fish in a type of a dough mixed with water for 6 weeks (Exp1) and switched to the EP containing 2.7% monobasic potassium phosphate (MKP) for subsequent 6 weeks (Exp2). Leafy vegetables of 8 cultivar were employed in the experiment and water quality [dissolved oxygen (DO, mg/L), pH, water temperature (℃), electrical conductivity (EC; ㎲/cm), turbidity (NTU), TAN (NH3 + NH4+) (mg /L), NO2-N (mg/L), NO3-N (mg/L) and PO4-P (mg/L)] was measured 6 times a week. Leafy vegetable productivity (HBFT-AP vs HP) was compared in respective experiment, which was similar or somewhat higher in HBFT-AP. During the 12-week feeding trial, concentrations of nitrite (NO2-N) and phosphorus (PO4-P) were kept low in variability while total ammonia nitrogen (TAN) and NO3-N levels increased with time in HBFT-AP. At the end of two feeding trials, values of weight gain (WG, %), feed efficiency (FE, %), specific growth rate (SGR, %) and protein efficiency ratio (PER) were higher in Exp2 than in Exp1. As well, higher values in hematocrit (PCV, %), plasma K (mEq/L) and inorganic phosphorus (mg/dL) were found (p < 0.05) in Exp2 where fish were fed the EP (EP: 38.60%, 2.80 mEq/L and 7.04 g/dL; Mash: 33.20%, 1.95 mEq/L and 5.50 g/dL). Leafy vegetables in HBFT-AP using Japanese eel fed the EP with MKP 2.7% had a productivity similar (4 kinds of cultivar) or somewhat higher (4 kinds of cultivar) compared to those in HP. Also, Japanese eel fed the EP showed higher values of Pi (m/dL) and K (mEq/L) in plasma compared to those fed commercial powder diet.

The Extrapolations to Reduce the Need for Pesticide Residues Trials on Continuous Harvesting Leafy Vegetables (농약 잔류 시험을 위한 연속수확 엽채소류의 외삽)

  • Son, Kyeong-Ae;Im, Geon-Jae;Hong, Su-Myeong;Kim, Chan Sub;Gil, Geun-Hwan;Jin, Yong-Duk;Kim, Jinba;Ihm, Yang Bin;Ko, Hyeon Seok;Kim, Jang Eok
    • The Korean Journal of Pesticide Science
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    • v.17 no.4
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    • pp.293-301
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    • 2013
  • This study was carried out to investigate the pesticide residue pattern among different leafy vegetables applied with foliar spraying under greenhouse and to check extrapolating from some residue trial data to other minor crops. Leafy vegetables used in this study were: Mustard greens (Brassica juncea L.), Kale (Brassica oleracea L.), Dacheongchae (a kind of pak-choi (Brassica rapa subsp. chinensis L.)), Leaf broccoli (Brassica oleracea var alboglabra), Perilla leaf (Perilla frutescens (L.) Britton var. Frutescens), Leaf lettuce (Lactuca sativa L.), Swiss chard (Beta vulgaris L. subsp. vulgaris) and Red leaf chicory (Cichorium intybus L. var. foliosum Hegi). These are cultivated all year under indoor or outdoor and cut the leaf from plant continuously during harvest time. The amounts of pesticide deposit in/on the continuous harvesting leafy vegetables were affected by the ratios of leaf area to weight. Ratio of perilla leaf was the largest among crops as 58 $cm^2/g$. The residue levels of 7 pesticides in/on perilla leaf were the highest than those of other crops through the statistical analysis from zero day to fifth day after last application. The representative crop in 8 crops was perilla leaf selected based on the amounts of daily consumption and the high residues. This study suggest that the continuous harvesting leafy greens should be separated from the one time harvesting leafy vegetables for the pesticide recommendations because of different harvesting habits and pre-harvest intervals.

The residue property of fungicide boscalid and fluidioxonil at the same time harvest leafy-vegetables (일시수확 엽채류에서 살균제 Boscalid와 Fludioxonil의 잔류특성)

  • Bae, Byung-Jin;Lee, Hae-Kuen;Son, Kyeong-Ae;Im, Geon-Jae;Kim, Jin-Bae;Kim, Tae-Hwa;Chae, Seok;Park, Jong-Woo
    • The Korean Journal of Pesticide Science
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    • v.16 no.2
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    • pp.98-108
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    • 2012
  • In order to use in the classification of minor crop for the mutual application of safe use guideline, it was investigated the residue property of fungicide boscalid and fludioxonil at the same time harvest leafy-vegetables, such as spinach, ulgaribaechu, vitaminchae and cheongkyungchae. After pesticides were applied 2 times with 1 week interval in that day of harvest, 2 days, 5 days and 7 days before harvest, vegetables were harvested, and the residue of pesticides was investigated. Base on the residue in that day of harvest, the deposit of spray solution in vegetables was calculated. The deposit of spray solution of boscalid was 253.9 mL/kg in spinach, 83.0 mL/kg in ulgaribaechu, 97.8 mL/kg in vitaminchae, and 88.3 mL/kg in cheongkyungchae, respectively. In case of fludioxonil, it was calculated 157.6 mL/kg in spinach, 67.6 mL/kg in ulgaribaechu, 64.8 mL/kg in vitaminchae, and 66.6 mL/kg in cheongkyungchae, respectively. When the amount of the deposit of both pesticides was compared in leafy-vegetables, it was the highest in the spinach. On the other hand, it was estimated the predicted dissipation curve of pesticides in leafy-vegetables during cultivation. The half-life of boscalid was 5.9 days in spinach, 7.4 days in ulgaribaechu, 4.6 days in vitaminchae, and 4.3 days in cheongkyungchae, respectively. Also, it was estimated half-life in fludioxonil, it was 3.0 days in spinach, 4.0 days in ulgaribaechu, 3.2 days in vitaminchae, and 3.5 days in cheongkyungchae, respectively. The half-life was the longest in the ulgaribaechu. When both pesticides were compared with the residue property, the deposit of spray solution and half-life of dissipation of boscalid were more than those of fludioxonil.

Monitoring of Pesticide Residues in Leafy Vegetables Collected from Wholesale and Traditional Markets in Cheongju (청주지역 도매 및 재래시장 유통 엽채류 중 잔류농약 모니터링)

  • Noh, Hyun-Ho;Park, Young-Soon;Kang, Kyung-Won;Paik, Hyo-Kyung;Lee, Kwang-Hun;Lee, Jae-Yun;Yeop, Kyung-Won;Choi, Song-Rim;Kyung, Kee-Sung
    • The Korean Journal of Pesticide Science
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    • v.14 no.4
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    • pp.381-393
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    • 2010
  • In order to monitor the residual characteristics of the pesticides in leafy vegetables selling at wholesale markets and traditional markets in Cheongju, a total of 180 samples of 15 leafy vegetables, such as broccoli, celery, chard, chicory, Chinese vegetable, Chwinamul, crown daisy, Korean cabbage, leek, lettuce, perilla leaves, Shinsuncho, spinach, welsh onion and young radish, were purchased from the wholesale markets and traditional markets in June and August in 2010 and the pesticide residues in them were analyzed by multiresidue analysis method using GLC, HPLC and GC-MSD. Seven pesticides were detected from 12 samples out of total 180 samples collected, representing detection rate was 6.7%. In case of the samples collected from markets in June, four pesticides including tefluthrin were detected from six samples and in case of the samples collected from markets in August, three pesticides including pendimethalin were detected from three samples. The MRL-exceeding rate of pesticides detected from leafy vegetables was 0.6%. The pesticide exceeded its MRL was azoxystrobin detected from crown daisy and many pesticides were not registered to the crops, excepting that azoxystrobin detected from Chwinamul and tefluthrin from leek. Estimated daily intakes (EDIs) of the pesticides detected from leafy vegetables were less than 7% of their acceptable daily intakes (ADIs), representing that residue levels of the pesticides detected were evaluated as safe.

Potential Control of Foodborne Pathogenic Bacteria by Pediococcus pentosaceus and Lactobacillus graminis Isolated from Fresh Vegetables

  • Gonzalez-Perez, C.J.;Vargas-Arispuro, I.;Aispuro-Hernandez, E.;Aguilar-Gil, C.L.;Aguirre-Guzman, Y.E.;Castillo, A.;Hernandez-Mendoza, A.;Ayala-Zavala, J.F.;Martinez-Tellez, M.A.
    • Microbiology and Biotechnology Letters
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    • v.47 no.2
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    • pp.183-194
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    • 2019
  • The consumption of fresh vegetables has been related to recurrent outbreaks of foodborne diseases (FBD) worldwide. Therefore, the development of effective alternative technologies is necessary to improve the safety of these products. This study aimed to isolate and identify epiphytic lactic acid bacteria (LAB) from fresh fruits and leafy vegetables and characterize their antagonistic capacity due to their ability to produce bacteriocins or antibacterial compounds. For this, 92 LAB isolates from fruits and leafy vegetables were screened for antagonistic activity. Two strains with the highest and broadest antagonistic activities were selected for further characterization; one from cantaloupe melon (strain CM175) and one from cilantro leaves (strain C15). The cell-free supernatants (CFS) of CM175 and C15 were found to exhibit antagonistic activity against FBD-causing pathogens. The CM175 and C15 strains were identified as Pediococcus pentosaceus and Lactobacillus graminis, respectively. Notably, the P. pentosaceus CM175 CFS stopped the growth of Salmonella Typhimurium, Salmonella Saintpaul, Staphylococcus aureus, and Listeria monocytogenes, and delayed Escherichia coli O157:H7 growth. Moreover, L. graminis C15 CFS delayed the growth of all indicator pathogens, but did not completely stop it. Organic acids and bacteriocin-like molecules were determined to be possibly exerting the observed antagonistic activity of the identified LAB strains. Thus, application of the antagonistic compounds produced by Pediococcus pentosaceus and Lactobacillus graminis could be a novel and ecological strategy in developing antimicrobial biopreservatives for the food industry and mitigating FBD by reducing the biological contamination in fruit and vegetable orchards, mainly via their potential in controlling both gram-negative and gram-positive pathogenic bacteria.

Effect of Surfactant Addition on Se Absorption and Growth of Pak-choi and Leaf Lettuce in Hydroponics (수경 재배 시 계면 활성제 첨가가 상추와 청경채의 생육과 Se 흡수에 미치는 영향)

  • Yuna, Hyung-Kwon;Seo, Tae-Cheol;Zhang, Cheong-Hao;Chun, Chang-Hoo
    • Journal of Bio-Environment Control
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    • v.18 no.2
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    • pp.124-131
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    • 2009
  • Surfactant polyvinyl alcohol (PVA-95) 1, 2, 4mg. $L^{-1}$ and calcium lignosulfonate (CLS) 5, 25, 50, 100mg. $L^{-1}$ were treated to the nutrient solution containing 1.0mg. $L^{-1}$ selenium (Se) to evaluate Se absorption effect using small DFT apparatus. The growth of leaf lettuce and pak-choi did not show unique significance by surfactant kinds and concentration in the tested range and physiological disorder. Vitamin C in leaves of two leafy vegetables was not significantly affected by surfactants also. Among major cations K content in pak-choi was highest in Se I+PVA-95 4mg. $L^{-1}$ treatment, and high in Se I+CLS 5 mg. $L^{-1}$ treatment. Ca content in two leafy vegetables showed increasing pattern by the two kinds of surfactants. Mg content was high in Se I+CLS 25mg. $L^{-1}$ treatment compared to control. Pak-choi absorbed Se about 10 times higher than leafy lettuce. Se content in leaves of two leafy vegetables increased by the treatment of two kinds of surfactants with the exception of CLS 100mg. $L^{-1}$ treatment.