• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.204-208
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• 2006

This study was conducted to develop a processing procedure for soft drink and wine from purple sweetpotato and to determine the color stability of purple sweetpotato anthocyanin pigment after production. Purple sweet potato soft drink was found to have 15.6% of total extraction, $11.8\;Brix^{\circ}%$ of sugar and pH 4.1, whereas wine had 12.6% of alcohol, $7.8\;Brix^{\circ}%$ of sugar and pH 4.9.Color stabilities of the soft drink and wine showed little difference after four-month storage from the time right after processing. The public found the soft drink that was made from 90% of purple sweet potato, 5% of citron and 5% of honey, more to their taste, rather than other soft drinks that were either made from 100% purplesweet potato or made from 80% of purple sweet potato, 10% of citron and 10% of honey. The public also found $45^{\circ}C$. of fermentation temperature more agreeable than that of $30^{\circ}C$. Powder, vinegar and anthocyanin pigment earned from purple sweet potato showed high stability, as they showed no change in color after four months in storage.

• Plant Resources
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• v.7 no.3
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• pp.200-205
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• 2004

Sweet potato infected with a viral disease (SPFMV) showed irregular chlorotic patterns, so called feathering associated with faint or distinct ring spots that have purple-pigmented borders. SPFMV was eliminated from sweet potato plants using meristem tip culture. MS medium supplemented with BAP (2mg/L) and NAA (0.05 mg/L) was used for shoot proliferation and 1/2 MS medium for rooting of the plants. Highest percentage of regenerated plants (60%) was obtained from the optimum size (0.3-0.5mm) meristem tips. Of these, 60% plants were found negative for SPFMV by RT-PCR. Virus detection by RT-PCR was found to be a reliable method. Meristem-tip culture to produce SPFMV-free quality sweet potato and virus detection by RT-PCR is an efficient, time saving and reliable method for production of SPFMV-free tissue culture raised plants.

• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.60-65
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• 2009

Cookies were prepared by adding different levels (0, 5, 10, 15, and 20%) of purple sweet potato powder (PSPP) and their physicochemical and sensory characteristics were examined. With increase of the PSPP level, moisture content decreased and ash content increased (p<0.05). The spread factor of control cookies was higher than that of cookies containing PSPP. The incorporation of PSPP in cookies lowered the lightness and yellowness but increased redness (p<0.05). Texture measurement showed that the addition of PSPP did not affect the hardness of cookies. Results of acceptance test revealed that overall acceptability score was not significantly different between the control and the PSPP added cookies. Therefore, it is suggested that PSPP can be incorporated into cookies up to 20% without affecting the cookie quality. Total polyphenol content and antioxidant activity were assessed to examine the functionality of cookies. In addition, substitution of wheat flour with PSPP yielded cookies with higher polyphenol content and antioxidative activity (p<0.05). The peroxide value (POV) and acid value increased during storage at $60^{\circ}C$ for 80 days. The POV was significantly lower in cookies containing PSPP than the control cookies, suggesting that the addition of PSPP deterred the lipid oxidation (p<0.05).

• Nutrition Research and Practice
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• v.7 no.5
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• pp.359-365
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• 2013

Anthocyanin from purple sweet potato (PSP) extracted by microwave baking (MB) and acidified electrolyzed water (AEW) exhibited antioxidant activity. After further purification by macroporous AB-8 resin, the color value of PSP anthocyanin (PSPA) reached 30.15 with a total flavonoid concentration of 932.5 mg/g. The purified extracts had more potent antioxidant activities than the crude extracts. After continuously administering the PSP extracts to 12-mo-old mice for 1 mo, the anti-aging index of the experimental group was not significantly different from that of 5-mo-old mice. To a certain degree, PSPA was also effective for controlling plasma glucose levels in male Streptozocin (STZ)-treated diabetic mice. In addition, the extracts inhibited Sarcoma S180 cell growth in ICR mice. Mice consuming the PSP extracts formed significantly fewer and smaller sarcomas than mice consuming the control diets. The highest inhibition rate was 69.03%. These results suggest that anthocyanin extracts from PSP not only exert strong antioxidant effects in vitro, but also had anti-aging, anti-hyperglycemic, and anti-tumor activities.

• Korean journal of food and cookery science
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• v.32 no.6
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• pp.677-685
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• 2016

Purpose: Molecular press dehydration is one of the dehydration methods. The purpose of this study was to investigate the quality characteristics of tarts made with dehydrated purple sweet potatoes during the storage period. Methods: Quality characteristics of purple sweet potato tarts were evaluated by analyzing moisture content, water activity, total phenolics, anthocyanins, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, color, and sensory evaluation for 45 days of storage. Results: Moisture content of tart crust made with molecular press dehydration treated purple sweet potatoes with concentrations of 20%, 40%, 60%, and 80% maltodextrin as a dehydrating agent for 45 days was 8.47%, 7.95%, 6.96%, and 6.24% respectively; however, the moisture content of non-treated tart crust was 11.99% (p<0.05). Total phenolics, anthocyanins, and DPPH free radical scavenging activity of dehydrated purple sweet potato tarts were lowered than those of non-treated tart (p<0.05). Conclusion: These results indicated that tarts made with molecular press dehydrated purple sweet potatoes had effectively controlled moisture content and water activity during storage although total phenolics, anthocyanins, DPPH free radical scavenging activity, color, and sensory evaluation were decreased.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.819-825
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• 1995

Two sweet potato CV.(Ipomoea batatas) were examined, i.e. purple flesh sweet potato(PSP) and light yellow flesh sweet potato(LYSP) which varied in degree of sweetness. On a fresh weight basis, nitrogen free extract in cultivars ranged from $25.73{\sim}26.24%$ and PSP contained more crude fat than LYSP. Total amino acids of PSP and LYSP were 5676.57mg% and 4550.86mg%, respectively. Aspartic acid, serine, alanine and valine were the major components in sweet potatoes. Sulfur-containing amino acids are the first limiting amino acid in PSP. The major fatty acids in PSP and LYSP analyzed by GC were palmitic acid, linoleic acid. The content of the saturated fatty acid was less than that of the unsaturated fatty acid. Carbohydrate contents were $75.43{\sim}79.10%$ and neutral sugars contents were $67.22{\sim}64.85%$(dry wt). Two sweet potato CV. contained the most glucose of all neutral sugars. PSP contained 11.88% for uronic acid, 59.42% for starch. Free sugars of PSP(0.82%) was much less than that of LYSP(2.53%). The contents of thiamin, riboflavin and niacin were similar, and the ascorbic acid contents in PSP and LYSP were 63.4mg% and 48.7mg%(dry wt), respectively. Comparing the mineral content in PSP, K was the greatest element in concentration followed by mg, Ca, Na. The total dietary fiber(TDF) value was 13.43% in PSP, 9.79% in LYSP respectively. The ratio of soluble dietary fiber(SDF) content and insoluble dietary fiber(IDF) content to TDF content for PSP were 57.6%, 42.4%, respectively.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.907-912
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• 1997

Physicochemical characteristics of kochujang prepared with various raw materials, were investigated during 90 days of fermentation to obtain information for the industrial production of traditional kochujang. Reducing sugar contents of kochujang increased until 60 days but slightly decreased thereafter, showing highest value for malt added group. Ethanol contents increased after 45 days and were highest in Chinese matrimony vine group, followed by purple sweet potato and malt added groups. Amino nitrogen contents increased until the 45 to 60 days of fermentation, but ammonia nitrogen contents did not change significantly during fermentation. Amino and ammonia nitrogen contents were higher in soy sauce and Chinese matrimony vine added groups. Water activities decreased slightly during fermentation and purple sweet potato added group was lowest among the groups. Consistency of kochujang decreased until the middle of the aging but after that it increased. Consistency of purple sweet potato and Chinese matrimony vine added groups were remarkably higher than that of the others. The color values tended to decrease slightly during fermentation. Purple sweet potato kochujang was low in the lightness, redness and yellowness. Results of sensory evaluation showed garlic and malt added kochujang were more acceptable than purple sweet potato added kochujang due to more desirable taste and color.

• Food Science and Preservation
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• v.19 no.6
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• pp.833-840
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• 2012

In this study, purple sweet potato muffins were made with the addition of 0, 25, 50, 75, and 100% rice flour, and their quality characteristics were determined. The weight and height increased with the increase in the amount of rice flour added. The moisture contents decreased significantly. As the amount of rice flour added increased, the pH and acidity decreased. The lightness and yellowness of the rice flour decreased significantly, but the redness increased with increasing purple sweet potato content. The textural properties, such as the cohesiveness, chewiness, and brittleness, were significantly lower in the groups with added rice flour. The DPPH radical scavenging activity was significantly higher in the purple sweet potato muffins to which 50 and 75% rice flour were added compared to those in the control. The results of the sensory evaluation showed that there was no significant difference in flavor among the samples. The chewiness was higher with 50, 75, and 100% rice flour than with 0 and 25% rice flour. The groups with 50 and 75% rice flour had significantly higher scores for overall acceptability compared to the control group.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.23-29
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• 2010

Pigment concentrates with violet-red color and sweet taste were obtained from purple-fleshed sweet potato(PFSP) using ethyl alcohol and water. Extract from general potato(GP) were used as a control. The relative stability of PFSP pigment concentrate(PFSPPC) in a storage test over 15 days was confirmed in the order of dark > fluorescence > sun-light irradiation. The relative stability of GP pigment concentrate(GPPC) in a storage test over 15 days was confirmed in the order of sun-light > fluorescence > dark storage. The RRP of PFSPPC was higher than that of GPPC, but the color strength of GPPC was 1/2 that of PFSPPC. Treatment of PFSPPC with aluminum potassium sulfate(0.2~0.3%, w/w) best improved its stability. The improved RRPs of PFSPPC were 45.16~47.31% in sun light irradiation, 55.91~60.22% in fluorescence irradiation, and 76.34~75.97% in dark storage conditions. In substituting aluminum potassium sulfate for chitosan, an amount of 0.2~0.3%(w/w) was suitable, giving similar results in improving pigment stability for all concentrates tested. Also, freeze-dried PFSPPC powder was manufactured as a substitute for dextrin, and also as a substitute for chitosan to the extent of 0.25%(w/w). The results of storage stabilite for freeze-dried PFSPPC and GPPC powder over 15 days, irradiation were, PRRs of 74.47~89.36% and 61.54~76.92%, respectively. The stability improving effect of freeze dried PFSPPC powder was confirmed by the results of storage experiments at various conditions. The use of freeze-dried PFSPPC powder was therefore confirmed to be an effective treatment for general foods.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.4
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• pp.660-666
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• 2015

Natural food colorant are widely used to satisfy consumer preferences. Anthocyanins are red, blue and purple natural pigments. Purple-fleshed sweet potato (PSP) contains large quantities of anthocyanins. The aims of this work were i) to investigate the influence of sugars on the purple color of PSP jam and ii) to optimize the ratio of ingredients for sensory characteristics of PSP jam. Korean PSP variety "Sinjami" was used for the preparation of jam. The jams were prepared with various sugar contents (0, 20, 30, 40 and 50% total weight) consisting of steamed purple-fleshed sweet potato, water, lemon juice and apple juice. With increasing sugar contents, lightness (L) and redness (a) of PSP jams decreased while yellowness (b) increased, indicating that anthocyanins were degraded and/or brown pigments were formed due to high sugar content under heat treatment. Hardness, springiness, chewiness and cohesiveness showed significant differences among PSP jams with various sugar contents. In sensory evaluation, addition of sugar significantly increased scores for color and texture as compared to control samples. The color, texture and preference results indicate an optimal sugar content of 40% total ingredient weight for PSP jam.