• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.38-43
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• 2018

A few authors have already investigated microbial contamination of leafy vegetables in distribution condition and examined the effect of temperature abuse on microbial safety or product quality. But this study analyzed proliferation of indicator microorganisms and food poisoning bacteria in real situation in Korean agroindustry and investigated washing effect of micobial contamination on leaf surface. Leafy vegetables were found to be contaminated with aerobic bacteria at $0.1{\sim}0.32{\times}10^3CFU/g$. Staphylococcus aureus and Bacillus cereus were detected in leafy vegetables at $0{\sim}0.54{\times}10^3CFU/g$. However, Salmonella spp., Coliforms, Clostridium spp. and Listeria spp. were not detected in any samples. Indicator microorganisms and food poisoning bacteria on leafy vegetables increased at room temperature when simulatively distributed condition. After clean-up, the indicator microorganisms and food poisoning bacteria of kimchi cabbage, lettuce and perilla leaf were decreased to a very low level. This study suggests that it is necessary to improve the level of hygiene management such as use of cold chain system and hygiene management of transport tools during the distribution process for fresh leafy vegetables.

• Journal of Radiation Protection and Research
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• v.46 no.4
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• pp.178-183
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• 2021

Background: This study was carried out to provide environmental transfer parameter values to estimate activity concentrations of these radionuclides in agricultural crops when direct contamination occurred. Materials and Methods: Mass interception fractions (F_Bs) and weathering half-lives (T_ws) of ¹³¹I and radiocesium were calculated using openly available monitoring data obtained after the Fukushima Daiichi Nuclear Power Plant accident. F_B is the ratio between the initial radioactivity concentration of a radionuclide retained by the edible part of the plant (Bq·kg^-1 fresh weight [FW]) and the amount of deposited radionuclide in that area (Bq·m^-2). T_w values can be calculated using activity concentrations of crops decreased with time after the initial contamination. Results and Discussion: Calculated F_B and T_w values for ¹³¹I and radiocesium were mostly obtained for leafy vegetables. The analytical results showed that there was no difference of F_Bs between ¹³¹I and radiocesium by t-test; geometric mean values for leafy vegetables cultivated under outdoor conditions were 0.058 and 0.12 m²·kg^-1 FW, respectively. Geometric mean T_w value of ¹³¹I in leafy vegetables grown under outdoor conditions was 8.6 days, and that of radiocesium was 6.6 days; there was no significant difference between T_w values of these radionuclides by Wilcoxon rank sum test. Conclusion: There was no difference between ¹³¹I and radiocesium for F_Bs and T_ws. By using these factors, we would be able to carry out a rough estimation of the activity concentrations of ¹³¹I and radiocesium in the edible part of leafy crops when a nuclear accident occurred.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.2
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• pp.175-180
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• 1997

Beta-carotene and lutein contents in 7 different green leafy vegetables(perilla leaf, mugwort, chwi, lettuce, spinach, leek, and crown daisy) were analyzed by HPLC. The isocratic separation was performed on a ${\mu}-Bondapak$ $C_{18}$ column with a solvent system of acetonitrile : dichloromethane : methanol = 70:20:10. To check the reliability of the method applied, precision and recovery tests were performed. Perilla leaf showed the highest ${\beta}-carotene$ content(12,570 ${\mu}g$ / 100 g), followed by mugwort and chwi, all of those have ${\le}10,000\{\mu}g\{\beta}-carotene$ per 100 g vegetables. Green lettuce, spinach, leek, crown daisy and reddish brown lettuce contained 9,869, 6,689, 5,664, 3,601 and 3,299 ${\mu}g\{\beta}-carotene/100 g$, respectively, Lutein content was the highest in perilla leaf($13,718{\mu}g/100 g$) followed by chwi($11,989{\mu}g/100 g$), mugwort($11,522{\mu}g/100 g$), green lettuce($10,307{\mu}g/100 g$) and spinach($10,115{\mu}g/100 g$). ${\beta}-carotene$ contents in perilla leaf, mugwort, chwi and green lettuce were 47.8~49.6% of total carotenoids, and ${\beta}-carotene$ contents in the other green leafy vegetables analyzed were 37.7~41.4% Vitamin A contents of green leafy vegetables analyzed by HPLC were 2~6 times higher than the vitamin A values shown in food composition tables except crown daisy.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.967-976
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• 2023

Biochar is emerging as a promising substance for achieving carbon neutrality and climate change mitigation. It can absorb several nutrients via ion bonding on its surface functional groups, resulting in slow dissociation of the bonds. Biochar, like organic fertilizers, contributes to sustainable nutrient management. The purpose of this study was to investigate the effects of nutrient-coated biochar amendments on leafy vegetables production and soil fertility. The nutrient-coated biochar was produced by soaking rice husk biochar in a nutrient solution containing nitrogen (N), phosphorus, and potassium for 24 hours. Nutrient-coated biochar and organic fertilizers were applied to soil at a rate of 120 kg·N·ha^-1. The growth components of the leafy vegetables showed that nutrient-coated biochar led to the highest fresh weight (FW) of both lettuce and kale (i.e., 146.67 and 93.54 g·plant^-1 FW, respectively). As a result, nutrient-coated biochar amendments led to superior yield compared to the control treatment and organic fertilization. The elemental composition of leafy vegetables revealed that soil amended with nutrient-coated biochar resulted in higher nutrient contents, which was attributed to the high nutrient contents supplied by the rice husk biochar. Soil amendment with nutrient-coated biochar positively enhanced the soil fertility compared to amendment with organic fertilizer. Therefore, nutrient-coated biochar is a promising substance for enhancing agronomic performance of leafy vegetables and improving soil fertility.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.211-218
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• 2018

Purpose: The present study investigated the nutritional and organoleptic characteristics of two African leafy vegetables (ALVs)-jute mallow (Corchorus olitorius L) and cowpea (Vigna unguiculata)-at various drying temperatures. Methods: The thin-layer drying of cowpea leaves and jute mallow was studied at various temperatures ($40-100^{\circ}C$) in a convective laboratory dryer, and the nutrient profiles of the dried vegetables were determined. The nutrients considered were vitamins B2 and C, and ${\beta}$-carotene. The level of vitamin C was determined by high-performance liquid chromatography (HPLC), whereas the levels of ${\beta}$-carotene and vitamin B2 were determined by titration. Results: ${\beta}$-carotene was the most stable nutrient, whereas vitamin C was the least stable nutrient in both cowpea leaves and jute mallow. The drying parameters-temperature and time-revealed that temperature had the most profound effect on vegetable nutrient stability. Organoleptic tests were carried out on the fresh and dried vegetable; there were no significant differences in preference between the fresh and dried ALVs (95% confidence interval). Conclusions: The present study revealed that the vegetables can be preserved by drying, and the study could be used as a guide for effective drying of those vegetables.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.802-806
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• 2007

There has been growing interest in the antioxidative and anticarcinogenic effects of vegetables. This study was aimed at evaluating the antioxidative and antiproliferative activities of 13 leafy vegetables consumed in Korea. New-beet and ornamental kale contained >1,000 mg of polyphenolics/100g fresh weight (FW), which was the greatest amount among the test vegetable extracts. Ornamental kale also contained the greatest amount (232.84 mg/100g FW) of flavonoids. With the exception of chicory, values of 1.1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities showed similar trends. New-beet was found to be the greatest antioxidant among the test vegetable extracts. New-beet exhibited the highest antiproliferative activity (>60%) against all tumor cells. No relationship was found between antiproliferative activity and antioxidant contents or antioxidant activities among samples.

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.193-202
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• 2023

Residue monitoring of propiconazole (PCZ) in cabbage, shallot, and spinach was conducted under multi-trial greenhouse conditions. This study aimed to understand the fate of the applied fungicide in these vegetables. Furthermore, the associated health risk of PCZ in leafy vegetables was assessed through dietary risk assessment. Commercially available PCZ (22% suspension concentrate) was administered thrice according to the OECD fungicide application interval guideline. The plant samples were extracted using a slightly modified QuEChERS technique and analyzed using gas chromatography-tandem mass spectrometry. The average PCZ recovery was between 84.5% and 117.6%, with a <5% coefficient of variance. The dissipation of PCZ residue in cabbage, shallot, and spinach after 14 days was 96%, 90%, and 99%, respectively, with half-lives of <5 days. Meanwhile, dietary risk assessments of PCZ residues in the studied vegetables using the risk quotient (RQ) were significant < 100 (RQ < 100). Thus, the population groups considered in this study were not at substantial risk from consuming leafy vegetables sprayed with PCZ following critical, good agricultural practices.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.960-966
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• 2021

A technical approach to design and carry out an experiment to determine the uptake of selected radionuclides in site-specific conditions in Kuwait was developed and successfully executed for developing a radioecological decision support system. The radionuclides from soil-to-plant transfer factors have been obtained for leafy and non-leafy vegetables, and root crops cultivated in Kuwait. Two types of vegetated soils were selected and spiked with high concentrations of three relatively short-lived selected radionuclides (⁸⁵Sr, ¹³⁴Cs, and ¹³³Ba). The highest strontium and barium transfer factors were found in the order: leafy vegetables > root crops > non-leafy vegetables. The approximate range of radiocesium transfer factor was found to be low in all plant groups and was comparable to those reported elsewhere in different soil types of temperate and tropical environments. A strong negative correlation between the obtained transfer factors and the distribution coefficient of the radionuclide in soil was found. It is recommended to adopt the newly derived parameters for the sensitive areas in Kuwait and other Gulf countries instead of using the generic parameters, whenever dose calculation codes are used. This will help to more accurately assess and predict the end results of the committed effective dose equivalent through ingestion pathway.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.31-37
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• 2018

This study was conducted to evaluate the microbiological safety of leafy vegetables (perilla leaf and lettuce) in relation to cultivation methods. A total of 2,304 samples were collected from plants, harvesting tools and soil mulching film during the production and harvest stages from organic- and conventional- farms. From the samples, sanitary indicator microorganisms (total aerobic bacteria, coliforms, E. coli., Environmental Listeria, and yeast and mold) and pathogenic microorganisms (S. aureus, B. cereus, Salmonella spp., Clostridium spp., and L. monocytogenes) were analyzed. In the production stage of leafy vegetables, the sanitary indicator microorganisms was not detected regardless of cultivation method or it was detected to be less than $3.4\;Log\;CFU/100cm^2$. B. cereus and S. aureus were found to be 0.22~1.55 Log CFU/g in perilla leaf and lettuce produced by organic farms, and S. aureus was not detected and B. cereus was found to be 0.42~2.19 Log CFU/g in conventional farms. There were no significant differences between two cultivation methods. In the harvesting tools and soil mulching film, the contamination levels of sanitary indicator microorganisms and pathogenic microorganisms was low regardless of the cultivation method. However, there was a positive correlation ($R^2=0.4526$) in that the higher the microbial contamination level in the harvesting tool, the higher the microbial contamination on the surface of the plant. In addition, sanitary indicator microorganisms and pathogenic microorganisms were not detected or low in soil mulching during the production of organic leafy vegetables. As a result of this study, microbial hygiene control by soil mulching and harvesting tools was more important than difference of cultivation method in production of leafy vegetables.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.2
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• pp.159-172
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• 2019

This study investigated the effects of dietary monobasic potassium phosphate (MKP) on the growth of the far eastern catfish Silurus asotus and four leafy vegetables in a hybrid biofloc technology aquaponic system. To an experimental diet containing 45% protein and 7% lipid, 1, 2, 3 or 4% MKP was added and was designated as MKP1, MKP2, MKP3, and MKP4, respectively. The optimum MKP levels were determined for the growth of fish and four leafy vegetables over 10 weeks. After the 10-week feeding trial, weight gain, feed efficiency, specific growth rate and protein efficiency ratio were higher in the fish groups fed MKP2 and MKP3 than in the other groups (P<0.05). The growth of the four leafy vegetables was also higher in the fish groups fed MKP2 and MKP3. Water quality [dissolved oxygen, pH, water temperature, electrical conductivity, turbidity, total ammonia nitrogen (TAN), $NO_2-N$, $NO_3-N$ and $PO_4-P$] was measured six times a week using a portable water quality meter and reagent measurements. The TAN (4.58-20.40 mg/L), $NO_3-N$ (24.12-52.40 mg/L) and $PO_4-P$ (20.38-48.48 mg/L) levels increased with time, while the $NO_2-N$ level remained below 0.1 mg/L throughout the study.