• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.66-71
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• 2001

Kinetic parameters for the texture degradation of three varieties of sweet potato during heating were determined using two alternative methods, the biphasic model and the fractional conversion method. The texture degradation of sweet potatoes during heating could be expressed by two simultaneous first order reactions using the biphasic method, whose activation energies were ranged $71.0{\sim}75.1\;kJ/mol\;and\;48.4{\sim}59.6\;kJ/mol$ for the initial fast texture degradation reaction and the slow texture degradation reaction at a prolonged heating period, respectively. However, the whole texture degradation phenomena of sweet potatoes during heating could also be explained by a single first order reaction using the fractional conversion method. The activation energies were $67.5{\sim}75.3\;kJ/mol$, which were comparable with those of the first phase reaction for the texture degradation determined by the biphasic model. A kinetic compensation effect shown between the kinetic parameters determined by both methods indicates that both methods can be conveniently used to determine kinetic parameters for the texture degradation of sweet potatoes by heating.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.203-211
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• 1989

During hot air drying of root vegetables such as radish and sweet potatoes, shrinkage and casehardening occurred, and thereby the quality change appeared. Therfore the hot air drying apparatus in which air temperature, relative humidity and air velocity could be controlled was designed, and the drying and shrinking characteristics of radish and sweet potatoes were studied. Also the external factors that affected these characteristics were investigated. The whole drying process of radish and sweet potatoes could be divided into four different drying rate periods, namely constant rate period, first falling rate period, second falling rate period (a) and (b). The shrinking rate curve consisted of four periods nearly corresponding to drying rate periods. The shrinking rate slowly increased in the constant rate period, rapidly increased in the first falling rate period, and reached the highest value in the early period of the second falling rate period. The surface shrinkage was greatly affected by the thickness of sample, relative humidity and initial moisture content. The shrinking ratio was increased with decreasing thickness and increasing relative humidity and initial moisture content.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.212-217
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• 1989

The shrinking and overall drying rate equations which can accomodate experimental date and the rate of initial drying ratio were investigated. The results obtained from hot air drying experiments of radish and sweet potatoes were as follow. The drying rate constant and the order were affected by the thickness of sample and temperature. The empirical drying rate and shrinking equations at constant drying conditions (d=4mm, $Ta=50^{\circ}C$, RH=10%, U=0.8m/s) for radish and sweet potatoes were found to $dx/dt=0.112{\times}10^{-2}\;A(1-x)^{0.43}$, A=Ao(-0.480x+1) and rates of initial drying ratio were expressed of sample thickness, relative humidity and air velocity; for radish $dx/dt=0.0648(RH)^{-0.31}\;(d)^{-0.75}\;(U)^{0.39}$ and for sweet potatoes $dx/dt=0.0547(RH)^{-0.28}\;(d)^{-0.63}\;(U)^{0.37}$

• Journal of Applied Biological Chemistry
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• v.49 no.1
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• pp.1-7
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• 2006

Differential display reverse transcription PCR (DDRT-PCR) analysis was performed on lily 'Marcopolo' bulb scale for isolation of expressed genes during bulblet formation. Cu/Zn lily-superoxide dismutase (LSOD) of 872 bp gene, with ability to scavenge reactive oxygen in stress environment, was isolated. Northern blot analysis showed expression levels of LSOD maximized 12 days after bulblet formation. Ti plasmid vectors were constructed with sense and antisense expressions of LSOD gene and transformed into potato. Southern blot analysis of transgenic potatoes revealed different copies of T-DNA were incorporated into potato genome. In transgenic potatoes, lily SOD gene was overexpressed in sense lines and not in antisense lines. In native polyacrylamide gel electrophoresis analysis, additional engineered LSOD was detected in sense overexpressed transgenic line only. Transgenic potatoes were subjected to oxidative stress, such as herbicide methyl viologen (MV). Transgenic potato lines with sense orientation exhibited increased tolerance to MV, whereas in antisense lines exhibited decreased tolerance. In vitro tuberization of transgenic potato with sense orientation was promoted, but was inhibited in transgenic potato with antisense orientation.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.43-47
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• 1989

For identifying the cause of the difference from the texture of mealy potatoes-Namjak and soomi- and soggy Potatoes-Daeji and Dowon-, starch and pectic substances and their relating materials were analyzed, and polygalacturonase(PG) activity was measured. The shape and size of Namjak and soomi starch granules were circular and diameter ranged from 0.02 to 0.024 mm. In the meanwhile, Daeji and Dowon had two sizes of starch granules; larger one tend to be oval in shape and diameter of longer side ranged from 0.04 to 0.045 mm, that of narrower side ranged from 0.02 to 0.03 mm and smaller one was rather circular in shape and average deameter was below 0.005 mm. Oval shaped potato starch grancules under polarized light showed dark cross of V-shape, whereas circular granules showed cross shape. Total sharch contents of Namjak and soomi were higher than that of Daeji and Dowon. The changes of pectic substances were the decrease of the insoluble pectin and the increase of the soluble pectin, and the reduction of the total pectic substance content after cooking. This phenomena were more prominent in Namjak and Soomi than in Daeji and Sowon. PG activities of Namjak and Soomi were greater than Daeji and Dowon. Calcium contents of Namjak and Soomi were lower than Daeji and Dowon. Phytic acid contents of Namjak, Soomi, Daeji and Dowon were 0.093%, 0.096%, 0.078%, and 0.081%, respectively. Hardness of Namjak and Soomi were less than Daeji and Dowon. The mealy potatoes had higher starch contents, higher tendency to pectin solubilization, higher PG activities, lower calcium contents and less hardness than the soggy Potatoes.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.80-80
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• 2019

Potatoes were first introduced outside the Andes region four centuries ago, and have become an integral part of much of the world's food. Potatoes were first introduced into Europe in the 16th century and Korea in the early 19th century. It is the world's fourth-largest crop, following rice, wheat, and maize. In the nutritional aspects, potatoes contain abundant vitamins and minerals, as well as an assortment of phytochemicals such as carotenoids and natural phenols. Chlorogenic acid constitutes up to 90% of potato natural phenols. Due to the high content of potato functional compounds, it has known that potatoes are effective in the prevention of various human diseases. Recently, potato 'Seohong' was developed by RDA, and it has reported that they have a high-yield and dry matter content. Processing industry of potato generates high amounts of peel as a byproduct. It was reported as a good source of several beneficial functional ingredients including antioxidant effect. This study was conducted to enhance the utilization of the peel of Potato 'Seohong'. The anti-inflammatory effects on solvent fraction was evaluated. The anti-inflammatory activities of Ethylacetate fraction was evaluated for inhibitory activities against lipopolysacchride (LPS) induced nitric oxide (NO) in RAW264.7 cell lines. The fraction inhibitory activity for tests with $IC_{50}$ values showed in the ranges of $50{\mu}g/ml$. This result revealed that n-butanol fraction of 'Seohong's peel is expected to be good candidate for development into source of anti-inflammatory agent.

• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.356-364
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• 2021

This study was carried out to investigate the effects of supercritical carbon dioxide (SC-CO₂) extracts from sweet potatoes (SP) and watermelon (WM) on the oxidative stability of perilla seed oils (POs) over the existing ones. A comparison was done between the oxidative stability of perilla oil (PO) after the addition of 0.1% of SP, and WM extracts and PO without extract. The oxidative stability was measured based on the viscosity, acid value (AV), peroxide value (POV), antioxidant (DPPH) activity, p-anisidine value (p-AV), and fatty acid composition. The viscosities ranges were: PO without extract, from 53.99±0.99 to 74.38±1.61 cps, PO with SP extract, from 53.99±0.10 to 58.73±0.8 cps, and PO with WM extract, from 53.98±0.10 to 56.00±0.70 cps. While the PO containing the SC-CO₂ extracts had significantly lower AV, POV, and p-AV, their antioxidant activity was approximately 10 times higher than that of the PO without extract. There were no significant differences in fatty acid composition between SC-CO₂ extracts added groups and PO without extract (p<0.05). The findings of this study confirmed that the SC-CO₂ extracts from sweet potatoes and watermelon enhanced the oxidative stability of perilla seed oils, and are potential natural antioxidants for use in the food industry.

• Journal of Drive and Control
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• v.21 no.2
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• pp.23-29
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• 2024

Potatoes are one of the world's four major crops, and domestic consumption is currently increasing in Korea. However, the mechanization rate of potatoes is very low, and especially, harvesting is the most labor-intensive task in potato production. In Korea, potato-collecting work depends on manpower, so it is necessary to develop a gathering-type harvester that can be used for processes from digging to harvesting. Therefore, in this study, a self-propelled-type potato harvester was developed, and its performance was analyzed to mechanize harvesting. The potato harvester was developed to have a crawler-type driving part with a 60 hp diesel engine and consisted of a digging part that digs potatoes from the ground, a vertical transporting part that transfers the dug potatoes to the height of the collection bag, a separating part that separates debris, such as stones and soil, and a collecting part that loads the collection box. A field test of the potato harvester was conducted, and performance was evaluated by the damage, loss, and debris mixing proportions, which were 2.5%, 2.8%, and 2.6%, respectively. The working capacity was 1.2 h/10 a. The economic analysis results showed that the cost of harvesting work could be reduced by 12.7% compared to manual harvesting.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.238-244
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• 2009

This survey was conducted as a surveillance program following the establishment of safety guidelines for agricultural products in Korea. Concentrations of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) were measured in 421 samples using a mercury analyzer or ICP-MS. The average levels of Pb in mg/kg were 0.021 for rice, 0.020 for corn, 0.028 for soybeans, 0.034 for red beans, 0.025 for sweet potatoes, 0.021 for potatoes, 0.019 for Chinese cabbage, 0.031 for spinach, 0.021 for Welsh onions, and 0.011 for radishes. The average levels of Cd in mg/kg were 0.021 for rice, 0.002 for corn, 0.020 for soybeans, 0.006 for red beans, 0.008 for sweet potatoes, 0.011 for potatoes, 0.007 for Chinese cabbage, 0.035 for spinach, 0.006 for Welsh onions, and, 0.006 for radishes. The average levels of As in mg/kg were 0.103 for rice, 0.005 for corn, 0.007 for soybeans, 0.005 for red beans, 0.005 for sweet potatoes, 0.004 for potatoes, 0.007 for Chinese cabbage, 0.015 for spinach, 0.009 for Welsh onions and, 0.006 for radishes. Finally, the average levels of Hg in ${\mu}g/kg$ were 2.3 for rice, 0.2 for corn, 0.6 for soybeans, 1.4 for red beans, 0.1 for sweet potatoes, 0.3 for potatoes, 0.5 Chinese cabbage, 2.1 for spinach, 0.5 for Welsh onions, and 0.2 for radishes. Based on the Korean public nutrition report 2005, these levels (or amounts) are calculated only at 2.6% for Pb, 8.7% for Cd, 1.2% 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.

• Korean journal of food and cookery science
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• v.19 no.2
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• pp.223-230
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• 2003

This study was conducted to estimate the contents of 6 trace metals in potatoes and root vegetables purchased in wholesale market in the Seoul region, specifically, Cu. As, Zn, Pb, Cd and Hg. The minimum and maximum results obtained for each metal are summarized as follows for potatoes; Cu : 0.094∼0.344, As : N.D∼0.070, Zn : 0.247∼1.547, Pb : N.D∼0.268, Cd : N.D∼0.005, Hg : 0.001∼0.027, and for root vegetables; Cu : 0.021∼0.510, As : 0.004∼0.045, Zn : 0.143∼3.137, Pb : N.D∼0.372, Cd : N.D∼0.009, Hg : 0.001∼0.195. The daily intakes of trace metals from potatoes and root vegetables were estimated on the basis of the daily intake of these foods by Koreans, which were 0.073∼22.253 and 0.567∼156.219$\mu\textrm{g}$ from potatoes and root vegetables, respectively. The weekly intakes of trace metals were 0.009∼2.596 and 0.066∼18.224$\mu\textrm{g}$ for potatoes and root vegetables, respectively. The weekly intakes of trace metals for potatoes and root vegetables were very much lower than the PTWI(provisional tolerable weekly intake), enough to be within a safe range.