• Journal of the East Asian Society of Dietary Life
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• v.19 no.5
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• pp.769-775
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• 2009

This study was performed to investigate the quality characteristics of yanggeng added with Purple Sweet Potato. The yanggeng was prepared with purple sweet potato, Agar, Sugar and Salt. The yanggeng is made with various levels(0, 2, 4, 6, 8%) of purple sweet potato added. Hunter's color value, texture profile analysis, and sensory characteristics of purple sweet potato yanggeng were examined. The addition of purple sweet potato has tendency to decrease the water content of yanggeng. As the content of purple sweet potato increased, the lightness(L) and yellowness(b) decreased and redness(a) increased. In texture profile analysis, hardness decreased with increasing purple sweet potato content. Cohesiveness and springiness didn't showed significant differences according to amount of purple sweet potato. The results of the sensory evaluation showed that the sweetness, softness and overall acceptability were the highest scores at yanggeng containing 4% level of purple sweet potato. In conclusion, the result shows that the yanggeng with 4% of purple sweet potato is the best.

• The Plant Pathology Journal
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• v.18 no.3
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• pp.126-129
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• 2002

Infected sweet potato (Ipomoea batatas) showing symptoms of sunken veins, stunting, mosaic, and mottling were collected from Gimje, Cochang, Iksan, and Haenam provinces in Korea. Electron microscopic (EM) observation of the infected tissue revealed rod and filamentous rod type virus particles of various lengths. Western blot analysis of the protein samples extracted from infected sweet potato and partially purified virus identified the isolates as Sweet potato feathery motile virus (SPFMV), Sweet potato latent virus (SwPLV), and Sweet potato chlorotic stint virus (SPCSV). Sweet potatoes were occasionally infected with more than one of these viruses. This is the first report of SwPLV and SPCSV in Korea.

• The Plant Pathology Journal
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• v.30 no.4
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• pp.416-424
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• 2014

Sweet potato is grown extensively from tropical to temperate regions and is an important food crop worldwide. In this study, we established detection methods for 17 major sweet potato viruses using single and multiplex RT-PCR assays. To investigate the current incidence of viral diseases, we collected 154 samples of various sweet potato cultivars showing virus-like symptoms from 40 fields in 10 Korean regions, and analyzed them by RT-PCR using specific primers for each of the 17 viruses. Of the 17 possible viruses, we detected eight in our samples. Sweet potato feathery mottle virus (SPFMV) and sweet potato virus C (SPVC) were most commonly detected, infecting approximately 87% and 85% of samples, respectively. Furthermore, Sweet potato symptomless virus 1 (SPSMV-1), Sweet potato virus G (SPVG), Sweet potato leaf curl virus (SPLCV), Sweet potato virus 2 ( SPV2), Sweet potato chlorotic fleck virus (SPCFV), and Sweet potato latent virus (SPLV) were detected in 67%, 58%, 47%, 41%, 31%, and 20% of samples, respectively. This study presents the first documented occurrence of four viruses (SPVC, SPV2, SPCFV, and SPSMV-1) in Korea. Based on the results of our survey, we developed multiplex RT-PCR assays for simple and simultaneous detection of the eight sweet potato viruses we recorded.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.2
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• pp.234-240
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• 2013

This study investigated the quality characteristics of gruel supplemented with purple sweet potato. The gruel was prepared with rice powder, salt, and various amounts of purple sweet potato (0, 2, 4, 6, 8%). Increasing the content of purple sweet potato decreased the pH and viscosity of the gruel, whereas sugar content and spreadability gradually increased. In addition, the content of purple sweet potato increased, the lightness (L) significantly decreased, while redness (a) and yellowness (b) increased. The results of the sensory evaluation show that overall-acceptability was highest for the gruel containing 6% purple sweet potato. In conclusion, the results shows that the gruel with 6% purple sweet potato is the best. This study indicates that it is possible to enhance the quality and acceptability of gruel by adding purple sweet potato powder.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.6
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• pp.750-759
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• 2013

In the study, purple sweet potato sponge cake was prepared with different ratios of purple sweet potato powder in order to examine the antioxidative activities and gelatinization characteristics. For DPPH radical scavenging effect, content of $IC_{50}$ came out with (+) control group of BHA. Sponge cake with purple sweet potato powder of 0% showed a range of 49.7 mg/mL, The treatment groups with purple sweet potato powder of 5~30% showed a range of 25.0 mg/mL~6.0 mg/mL. That was, the higher the added quantity of purple sweet potato powder was, antioxidative activities increased. With the higher quantity of purple sweet potato, the content of phenols and flavonoids also increased. As a result of examining the gelatinization activity with DSC, the group with purple sweet potato powder showed a faster progress in temperature for starting gelatinization compared to the control group. Gelatinization activity increased in proportion to the content of purple sweet potato powder. Based on the above study results, it was proved that there is a possibility to produce baking processed foods using purple sweet potato with stable gelatinization and excellent antioxidative activities.

• Korean journal of food and cookery science
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• v.24 no.4
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• pp.501-510
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• 2008

In this study, we evaluated the quality characteristics of sweet potato Sulgidduk produced with varying amounts of fresh sweet potato, after three days of storage. The more fresh sweet potato was added, the higher were the levels of crude protein and crude lipid; however, crude ash contents were lowest in the control sample, and no significant differences in this value were detected among the samples to which fresh sweet potatoes were added. Moisture contents evidenced a tendency to decrease with increases in the amount of added fresh sweet potato and increased storage time, but pH rose with increases in the amount of added sweet potato. Total cell counts showed a tendency toward decrease with increases in the amount of added fresh sweet potato. L values tended to be low with increases in the amount of added fresh sweet potato and a values were lowest immediately after its production, although no consistent tendencies were noted in correlation with the amount of added fresh sweet potato. b values tended to increase directly with the amount of added sweet potato . With increasing storage time, the L and a values decreased, whereas the b value tended to increase. Upon textural assessment, it was observed that hardness, adhesiveness, springiness, gumminess, and chewiness(all textural components except for cohesiveness) increased with increasing quantities of added fresh sweet potato, and these factors also tended to increase with the progression of storage time. After observation via scanning electron microscopy(SEM), it was noted that the cohesiveness also increased with increasing amounts of added sweet potato. With regard to the sensory evaluation, the samples to which 15% fresh sweet potato had been added evidenced the highest acceptability in terms of color, flavor, and s0weetness, and softness and moistness in these samples decreased with increasing percentages of added sweet potato. It has been previously demonstrated that the addition of 15% fresh sweet potato resulted in optimal overall acceptability. In accordance with the aforementioned results, it has been verified that the use of fresh sweet potato in Sulgidduk is possible and probably desirable, and an addition of 15% sweet potato appears to be the optimal approach in terms of overall quality and functionality.

• Korean journal of food and cookery science
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• v.7 no.2
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• pp.7-18
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• 1991

This study was experimented saccharification process added malt extract solution into cooked sweet potato and potato with time, temperature and was tested reducing sugar changes, structural changes, pH and sensory evaluation about cooked shik-hae of rice, glutinous rice, potato, sweet potato. The results are summarized as follows: 1. Enzyme activity was highest in malt after four days of barley germination at a room temperature. 2. Electronmicroscopic observation indicated that raw starch granule of potato and that of sweet potato was 25-60$\mu\textrm{m}$ and 8~18$\mu\textrm{m}$ in size, respectively and its shape is oval and globular for potato and sweet potato respectively. 3. Reducing sugars were 1,682.6mg and 1,695.6mg in rice and glutinous rice, respectively, for 6-hour-saccharification at $50^{\circ}C$. Reducing sugars were 1,689.1mg and 1,497.8mg in sweet potato, potato, respectively, for 6.hour-saccharification at $60^{\circ}C$. 4. pH variation during saccharification for sweet potato and potato was pH 5.8~5.4. 5. Sensory evalution showed that there were more significant differences in sweety odor, roasted nutty taste and sweety taste of sweet potato among four samples than the other's color shininess.

• Journal of the Korean Society of Food Culture
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• v.27 no.6
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• pp.730-736
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• 2012

This study was performed to investigate the qualities of jelly supplemented with purple sweet potato (C:0 g, P1:1 g, P3:3 g, P5:5 g, P7:7 g). The pH decreased (acidity increased) with the addition of purple sweet potato powder (p<0.01). The sugar content of the jelly also significantly increased when purple sweet potato was added. The DPPH radical scavenging activities of jelly increased as the addition of purple sweet potato increased. As the content of purple sweet potato increased, the L and b values decreased and the "a value" increased. In terms of textural characteristics, the addition of purple sweet potato increased hardness and springiness, while it decreased the cohesiveness. The results of the sensory evaluation showed that the appearance, flavor, taste, texture, and overall acceptability gave the highest score for jelly containing 5 g of purple sweet potato (P5).

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.943-947
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• 1995

The sweet potato drinks were prepared with the reaction of sweet potato and complex enzyme(${\beta}-amylase,\;{\alpha}-amylase$, protease). The reducing sugar and soluble solid of sweet potato drinks were the highest on reaction of sweet potato : water(1 : 1) and complex enzyme(pH 4.5). In the color of the sweet potato drinks, hunter value(L, a, b) were the lowest on reaciton of sweet potato : water(1 : 1) and complex enzyme, and were the highest on reaciton of sweet potato : water(1 : 3) and complex enzyme(pH 4.5). In the sensory test of the sweet potato drinks, the sensory score(color, taste, flavor, texture) were the best on reaction of sweet potato : water(1 : 1) and complex enzyme(pH 4.5). These results demonstrated that the sweet potato drink was good to drink when sweet potato : water(1 : 1) were treated with complex enzyme at pH 4.5, $60^{\circ}C$ for 5 hrs.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.1
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• pp.35-39
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• 2012

Sweet potato soju(SPS) has been made by vacuum distillation because sweet potato contains much fibrous materials which give high density to sweet potato mash. Generally, the SPS made by vacuum distillation has soft flavors and tastes. If the viscosity of sweet potato mash could be decreased by degradation enzyme, the process and production of SPS making by the method of vacuum distillation may be simplified and easier to distil the fermented sweet potato. Because the fibrous materials of sweet potato contains pectin with methoxyl group, methanol can be produced by fibrous degradation enzyme. For appling the fiber degradation enzymes to sweet potato mash for making SPS, the enzyme should be needed to degrade fibrous material without producing methanol. Special two fibrolytic enzymes are selected from 26 kind of commercial enzymes for the simplified and easier production of sweet potato soju by vacuum distillation, The selected enzyme A and X can degrade the fibrous material pectin of sweet potato without producing methanol. Although the different companies have produced the enzymes, same cellulase has been prepared from Trichoderma. reesei. The viscosity of sweet potato mash treated by the enzymes is decreased by 3 times with comparison to the viscosity of sweet potato mash of control group. The methanol concentration in the vacuum distilled SPS treated with the enzymes is 0.16%. The concentration is similar to that of commercially distilled SPS(0.15%). The result may suggest that the selected cellulases, A and X, can be used to make SPS by vacuum distillation.