• Preventive Nutrition and Food Science
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• v.5 no.1
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• pp.20-24
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• 2000

A study was carried out to establish the detection method of irradiated corn, potato, and sweet potato starches. The samples were packed in polyethylene bags and irradiated with 1, 3, 5, 7, 10, and 15 kGy using a Co-60 irradiator. The maximum viscosity of irradiated and unirradiated corn, potato, and sweet potato starches reduced by increase of irradiation dose levels and showed significant differences which clearly showed the effect of irradia-tion dose levels (p<0.05). Regression expressions and coefficients (p<0.000) or corn, potato, and sweet potato starches were y=-38.538x+718.23(r2=0.9761), y=669.97e-0.1372x (r2=0.9820) and y=-42.544x+730.26(r2=0.9939), respectively. Nor-malized parameter A,B and C values showed a dose dependent relationship and were a better parameter for detecting the irradiated starches than that of the maximum viscosity itself.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.92-96
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• 2004

Environmental factors such as soil moisture, land management, and weather conditions affecting Fusarium wilt of sweet potato were investigated in major sweet potato cultivation regions in Korea. Fusarium wilt occurred mainly in reclaimed terracing lands, which are flattened and located in hilly to mountainous areas at the base of the mountain, in early seasonal cultivation regions. Disease severity was lower in reclaimed fields with natural slope. The development of Fusarium wilt in the fields was highly correlated with precipitation during planting period (r=-0.96**). Fusarium wilt was more severe in fields with less than 20 cm of available soil depth than in fields with over 20 cm of available soil depth. Greenhouse studies were consistent with field studies that less soil moisture content caused severe Fusarium wilt of sweet potato. These results indicate that low rainfall and moisture of soil with low effective soil depth during planting period are important environmental factors influencing the development of Fusarium wilt.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.5
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• pp.402-406
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• 2003

Greenhouse and laboratory studies were conducted to determine the allelopathic potentials of extracts or residues from sweet potato (Ipomoea batatas L. (Lam). The extracts applied on filter paper in a Petri dish bioassay significantly inhibited root growth of alfalfa. Aqueous leachates at 40g dry tissue $\textrm{L}^{-1}$ (g $\textrm{L}^{-1}$) from leaves showed the highest inhibition against alfalfa, and followed by stems and roots. Alfalfa root growth was significantly inhibited by methanol extracts of the same plants as the concentration increased. The effect of residue incorporation into soil on seedling growth of com, soybean, barnyard grass and eclipta was examined in the greenhouse, and results showed that the leaf residues at 200g $\textrm{kg}^{-1}$ by plant parts inhibited shoot dry and root dry weights of test plants by 60-80%. By means of HPLC, causative allelopathic substances present in plant parts of sweet potato "Sinyulmi" were identified as coumarin, trans-cinnamic acid, o-coumaric acid, p-coumaric acid, and chlorogenic acid. Total content of these compounds for leaves extracts were detected as the greatest amount in EtOAc fraction, especially trans-cinnamic acid was the greatest component. These results suggest that sweet potato plants have herbicidal potentials, and that their activities exhibit differently depending on plant parts.ant parts.

• The Plant Pathology Journal
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• v.36 no.6
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• pp.651-657
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• 2020

Lotus is one of the most important aquatic vegetables in China. Previously, we detected sweet potato latent virus from lotus (SPLV-lotus) and found that it has highly significant sequence diversity with SPLV-sweet potato isolates (SPLV-sp). Here, we developed serological methods for the detection of SPLV-lotus in Chinese lotus cultivation areas. Based on the high sensitivity of SPLV-lotus coat protein antiserum, rapid, sensitive and large-scale diagnosis methods of enzyme-linked immunosorbent assay (ELISA) and dot blot in lotus planting area were developed. The established ELISA and dot blot diagnostic methods can be used to detect SPLV-lotus from samples successfully. And our results also showed that the SPLV-lotus and sweet potato isolates appeared clearly distinction in serology. Our study provides a high-throughput, sensitive, and rapid diagnostic method based on serology that can detect SPLV on lotus, which is suggested to be included in viral disease management approach due to its good detection level.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.790-795
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• 2000

To establish the optimum conditions for the extraction of anthocyanin pigment from purple-fleshed sweet potato, a suitable extraction solvent with the optimum citric acid concentration for acidification of the solvent, and the optimum extraction time and temperature were determined. Twenty percent ethanol solution acidified with citric acid was found to be a good solvent for the extraction of the pigment from purple-fleshed sweet potato. About 10 hour extraction at room temperature was appropriate for the extraction. pH of the extract was below 3 when more than 0.7% citric acid was added. The higher the concentration of citric acid added was, the higher the total optical density (TOD) of the extract was. However, the increase in TOD of the extract was insignificant when more than 1% of citric acid was added. Therefore, addition of 1% citric acid was determined for acidification of the extracting solvent. Though the initial rate of the pigment extraction increased as the extracting temperature increased, extraction at higher temperatures of 60 or 8$0^{\circ}C$ for an extended time caused a decrease in the extraction yield due to degradation of the pigment. The optimum extraction temperature for the anthocyanin pigment from purple-fleshed sweet potato with the solvent used was determined as 4$0^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.755-762
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• 2000

Physicochemical properties of commercial sweet potato starches manufactured by 7 different companies were investigated in comparison with corn and potato starches. Crude ash and protein content varied from 0.36 to 1.02%, and from 0.04 to 0.14% based on dry weight, respectively. The protein contents were relatively smaller than that of corn or potato starch. But whiteness of the sweet potato starches was less than that of corn or potato starch. Mean diameter of the sweet potato starch granules varied from 14.23 to $21.08\;{\mu}m$ depending on the company and all sweet potato starches showed bimodal size distributions. Pasting viscosity measured by Rapid Viscoanalyzer(RVA) also showed variations among the starches of different companies. The starch from D company in Korea had the lowest pasting temperature$(74.00^{\circ}C)$ whereas the starch from a phillippine company(P) did the highest one$(80.35^{\circ}C)$. The peak viscosity of sweet potato starches was higher than that of corn starch but lower than that of potato starch. The D company starch also showed the highest peak viscosity(2283 cp) among the starches tested. Paste breakdown by hot shearing ranged from 524 cp (S company) to 1279 cp (HL company). Textural properties of the starch gels appeared significantly different among the starches of different manufacturers. The greatest hardness of the gel was $137.90\;g_{f}$ at 1 day storage whereas the lowest value was $31.53\;g_{f}$. Except the starches from 2 companies (P and S), the sweet potato starches formed very soft and weak gels. P or S company starches formed the gels similar to potato starch. Syneresis by freeze-thawing treatments appeared less for sweet potato starch gels than that for corn starch gels, but greater than that for potato starch gel. The overall properties of the sweet potato starches varied by the manufacturing companies, and ranged between those of corn and potato starches.

• The Korean Journal of Food And Nutrition
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• v.9 no.3
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• pp.247-252
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• 1996

$\beta$-Amylase was purified from sweet potato by acetone fractlonatlon, Sephadex A-50 ion exchange chromatography and Sepgadex G-200 gel chromatographyl The higher enzyme concentration was, the higher heat stability of enzyme became. After 1 hour 30 minute. At 6$0^{\circ}C$ in pH 5, enzyme under concentration of 30$\mu$l/ml lost its activity completely and over the concentration of 100$\mu$g/ml remained 25% of activity. The enzyme was stabilized at range of pH 4~10 and pH stability was increased by glycerol. Five moles of NaCl inhibited completely of the enzyme activity. SDS of 0.05% inhibited the enzyme completely after 12 hours at 37$^{\circ}C$ in pH5. One mole guanidine-HCl and 8M urea inhibited the entire enzyme after 13 hours at 37$^{\circ}C$ in pH 5.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.596-602
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• 1998

Two kinds of sweet potato puree were prepared with Benihayato cultivar of yellow sweet potato with or without $\alpha$-amylase enzyme treatment. Chemical and rheological properties of enzyme-treated puree were different from those of control puree. Reducing sugar content and iodine value increased by $\alpha$-amylase enzyme treatment, while alcohol insoluble solids and viscosity decreased by enzyme treatment. However, the changes of carotenoid content were not significantly different. Hunter-b-values(yellowness) were 27.19 and 23.54 for no enzyme-treated puree(NTP) and enzyme-treated puree(ETP), respectively. Hunter-a values(redness) were 2.24 and 6.05 for NTP abd ETP, respectively. Content of total carotenoid of canned puree heated at 13$0^{\circ}C$ for 30 min decreased by 59 percents.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.821-825
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• 2003

The effects of purple sweet potato anthocyanin (SPA) and Cordyceps mushroom extract (CME) on lipid peroxidation, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and cognitive deficits were examined. Both SPA and CME exhibited DPPH radical scavenging activities with similar potency. In contrast, only SPA was shown to effectively inhibit lipid peroxidation initiated by $Fe^{2+}$ and ascorbic acid in rat brain homogenates. Furthermore, SPA markedly enhanced cognitive performance, assessed by passive avoidance test in ethanol-treated mice. Combined treatments with SPA and CME did not significantly influence the effects of SPA alone. These results demonstrate that anthocyanin prepared from purple sweet potato exhibits memory enhancing effects, which may be associated with its antioxidant properties.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.565-572
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• 2013

This study was performed to optimize the processing conditions and to select the optimum species for colored sweet potato chips (Shinjami, Juhwangmi and Hayanmi varieties) baked by far-infrared radiation. Sweet potato chips were prepared by different slicing thickness (1~3 mm), concentration of sucrose solution for soaking (15~30%), blanching time (15~60 sec), baking temperature ($110{\sim}140^{\circ}C$) and baking time (23~31 min) through sensory evaluation and failure stress measurement. Optimal processing condition of sweet potato chips using Shinjami was determined to 1 mm, 20%, 45 sec, $120^{\circ}C$ and 31 min, and those using Juhwangmi was determined as 1 mm, 25%, 45 sec, $130^{\circ}C$ and 29 min. Sweet potato chips using Hayanmi was determined as 1 mm, 20%, 45 sec, $120^{\circ}C$ and 31 min, respectively. Free sugar content of sweet potato chips was higher in chips than in raw materials. In the sensory evaluation, appearance, sweet taste, hardness, and overall acceptance were higher in Juhwangmi than in the Shinjami and Hayanmi varieties. Overall acceptance, sugar content, b-value and failure stress were highly correlated among factors affecting the sensory characteristics (p<0.01). From the results of this study, Juhwangmi variety was selected for production of sweet potato chips.