• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.673-677
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• 2002

To develop a new traditional liquors using purple-fleshed sweet potato, the condition of alcohol fermentation was investigated by adding different concentrations $(5{\sim}75%)$ of cooked purple-fleshed sweet potato into mash and 10% nuruk, and fermenting for $5{\sim}15$ days. The maximum amount of ethanol (15.4%) was produced when 20% cooked purple-fleshed sweet potato and 10% nuruk were added into mash and fermented by S. cerevisiae at $25^{\circ}C$ for 15 days. The acceptability and physiological functionalities of the purple-fleshed sweet potato liquors were also investigated and compared. PSP-10 purple-fleshed sweet potato liquor prepared by adding 10% cooked purple-fleshed sweet potato into mash showed the best acceptability in the sensory evaluation test and color test $(pink{\sim}red)$; its fibrinolytic, electron-donating, and tyrosinase inhibitory activities were better than those of other purple-fleshed sweet potato liquors and wine.

• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.311-316
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• 2015

Yogurt was prepared with different substitution ratio [10, 30, and 50% (w/w)] of skim milk with enzymatically hydrolyzed purple sweet potato powder (EHPSPP) and fermented at $40^{\circ}C$ for 15 h. Fermentation characteristics and antioxidant activities of the yogurt were evaluated in terms of acid production (pH and titratable acidity) and lactic acid bacterial counts and DPPH radical scavenging activity, respectively. After 15 h fermentation, titratable acidity of EHPSPP yogurt was 0.80-0.89% and was lower than that (0.93%) of yogurt made without EHPSPP. The acid production and the number of viable lactic acid bacterial cell decreased with increasing the substitution ratio. The sensory score of EHPSPP yogurt prepared with 30% substitution ratio showed the highest values in taste and overall acceptability among the tested yogurt preparations. DPPH radical scavenging activity increased with increasing the substitution ratio in yogurt fermented for 12 h. The total phenolic content of 30% EHPSPP yogurt was 40% higher than that of skim milk yogurt. These results suggest that EHPSPP can be used as substituent of skim milk and the optimum substitution ratio is around 30%.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.224-230
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• 2014

The characteristics and antioxidative activities of yellow and black soybean cheonggukjang prepared with the addition of purple sweet potato (Ipomoea batatas cv. Jami) were evaluated. In sensory evaluation experiments involving the addition of purple sweet potatoes to cheonggukjang at 0, 5, 10, 20, and 30% ratios (w/w), yellow (YCAP) and black (BCAP) soybean cheonggukjang with 20% purple sweet potato were most preferred. The total phenolics and flavonoid contents of YCAP and BCAP were higher than those of yellow (YC) and black (BC) cheonggukjang prepared without added purple sweet potato. YCAP and BCAP also showed higher DPPH radical-scavenging activities than other samples. Moreover, rat blood plasma samples taken 1 h after oral administration of YCAP and BCAP showed higher inhibitory effects against lipid peroxidation than did rats fed YC or BC. These results suggest that the long-term intake of cheonggukjang prepared with purple sweet potato may increase the antioxidative activity in the blood.

• Food Science and Preservation
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• v.23 no.4
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• pp.538-546
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• 2016

Kochujang was prepared by replacement of rice (25%, control) with pumpkin or purple sweet potato by 0. 5, 10, and 15% (total addition ratio of rice and sweet potato=25% of sample). Effects of the addition of sweet potato on physiochemical properties of fermented Kochujang were investigated. Viable cells of yeast decreased in the sweet potato-added Kochujang at the later stage of fermentation, while there was no significant difference in the number of bacteria among the test groups. As the addition ratio sweet potato increased, ${\alpha}$-amylase activity increased while protease activity decreased. Hunter L, a, and b values of Kochujang prepared with purple sweet potato were lower than those with pumpkin sweet potato. Changes in ${\Delta}E$ value was greater in Kochujang prepared with pumpkin sweet potato than that with purple sweet potato. Oxidation-reduction potential and water activity were higher in sweet potato-Kochujang than control, but reducing sugar content was higher in control. Alcohol and amino-type nitrogen contents were higher in Kochujang prepared with pumpkin sweet potato than that with purple sweet potato, but it was not significant. Overall sensory acceptability was highest in Kochujang prepared with 10% of purple sweet potato while that with 15% pumpkin sweet potato was the least preferred.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.395-401
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• 2012

Purpose: The purpose of this study was to research any effect on vision protecting or decreasing VDT syndrome of extracted anthocyanine from fermented purple sweet potato and blueberry. Methods: Subjects were aged 19-20 years old who do not have ophthalmic and systemic diseases and over -N4.00 D of refraction error. 40 mg of extracted anthocyanine from fermented purple sweet potato, from blueberry, and control group, placebo were dosed at separate try. After 2 hours later, subjects were directed perform visual display terminal (VDT) work for 2 hours. Objective refractive error was measured before dosing anthocyanine and after VDT work for 2 hours. Degree of head ache, eye pain and strain and subjective symptoms of neck, shoulder and waist was also examined through interviews by dividing its degree into severe, moderate, slight or none. Results: After 2 hours VDT work, vision protection effect in terms of refractive error for dominant eye was decreased by $0.031{\pm}0.21$ D in the group of extracted anthocyanine from fermented purple sweet potato, $0.006{\pm}0.32$ D in the group of extracted anthocyanine from blueberry. However, there was significantly myopic progression in the placebo group by $0.144{\pm}0.28$ D (t=2.27, p=0.03). Conclusions: It is considered that extracted anthocyanine from fermented purple sweet potato inhibits increase of refraction anomalies of dominant eye rather than non-dominant eye after VDT work.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.143-150
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• 2011

Lactic fermented dongchimi naengmyeun broth which has enhanced antioxidative activity was developed. During lactic fermentation of dongchimi naengmyeun broth at $25^{\circ}C$, changes of total lactic acid bacteria, pH, acidity, soluble phenolics, and anthocyanins were investigated. After 72 h of fermentation, the stronger antioxidant activities were observed in dongchimi naengmyeun broth supplemented with purple sweet potato than those of control dongchimi naengmyeun broth which showing 96.80% in DPPH radical scavenging activity, 100.82% in $ABTs^{+{\cdot}}$ scavenging activity, 7.77 in reducing power, and 6.89 in ferric reducing/antioxidant power, respectively. These high antioxidant activities related with higher contents of soluble phenolics and anthocyanins in dongchimi naengmyeun broth supplemented with purple sweet potato. The results suggest that the making of functional dongchimi naengmyeun broth by using high soluble phenolics and anthocyanins supplements such as purple sweet potato powder was possible.

• Food Science and Preservation
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• v.6 no.4
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• pp.442-447
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• 1999

A curd yogurt was prepared by fermenting milk added with skim milk powder and purple sweet potato by culture of 5 types of lactic acid bacteria(Lactobacillus delbruekii sub. sp. lactis, Streptococcus lactis, acidity, number of viable cell, stability of purple sweet potato's pigment and keeping qualify. Among the organisms tested, the acid production and number of viable cell by the culture of L bulgaricus remarkably increased for the first 12 hem which showed 1.04${\times}$10$\^$9/ CFU/mL in number of viable cell and 4.22 In pH where as fermentation by the culture of B. bifidum was slow. After 36 hours of incubation which showed 3.3 ${\times}$ l0$\^$8/ CFU/mL in number of viable cell and 5.1 in pH. In stabilities of purple sweet potato anthocyanin pigment n fermentation, yogurt by B. bifidum was found to be most stable followed by Leuc. lactis, L. delbruekii sub. sp. lactis, L bulgaricus, but yogurt by St. lactis was not stable. When curd yogurt added with Purple sweet Potato was kept at 2∼3$^{\circ}C$ for 14 day, its keeping quality(pH, titratable acidity, number of viable cell) was relative good except product by L. bulgaricus was found to be decreased most of viable cell. After 2 weeks of keeping, pigment of yogurt was decreased by B. bifidum, stable by L. delbruekii sub. sp. lactis.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.728-735
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• 2012

Makgeolli is the oldest Korean traditional wine made from rice, and contains 6-8% alcohol. Also, nuruk is traditionally prepared by exposing moistened ground wheat or rice to the air, and there contained airborne microorganism. In this study, purple sweet potato (PSP) was used as a raw material in the rice nuruk- and makgeolli-making processes. PSP rice nuruk (RN) was made with rice and 0-10% (w/w) PSP, and the characteristics of makgeolli were studied during fermentation. The pH during fermentation decreased from 4.27 (0% PSP-RN), 4.59 (2.5%), 4.50 (5.0%), 4.46 (7.5%), and 4.43 (10.0%) of initial fermentation day to 4.12, 3.82, 3.67, 3.71, and 3.66, respectively, at day 7. The sugar contents increased from $0.4^{\circ}Bx$ of the initial day to $8.0-8.4^{\circ}Bx$, and the levels of alcohol increased to 13.0% (0% PSP-RN), 13.2% (2.5%), 12.8% (5.0, 7.5, and 10.0%) by day 7, respectively. In addition, the contents of soluble anthocyanins and phenolics increased from 0.001-0.121 and 0.2-0.27 g/L on the initial fermentation day to 0.002-0.166 and 1.65-1.87 g/L, corresponding to increases in levels of antioxidant activities of 20-50%, respectively.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.29-34
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• 2013

The objective of this study was to manufacture three kinds of domestic sweet potato Makgeolli using a mixture design and an optimization technique. The effects of four different manufacture methods, such as simultaneous saccharification and fermentation (SSF) with or without malt and separate hydrolysis and fermentation (SHF) with or without malt were determined. The SSF methods of Makgeolli produced higher alcohol content than that of SHF methods. The sensory score was not influenced by different making methods. Fourteen experimental points were selected, and rice (10~50%), sweet potato (10~50%) and water (40~60%) were chosen as independent variables. The measured responses were sensory preference, total polyphenol content, and DPPH radical scavenging activities. The ratio of the optimum sweet potato Makgeolli mixture formulation was developed as 15.11 (rice): 44.89 (sweet potato): 40 (water) using the optimization technique. The desirability of the optimum mixture formulation was 0.839. Yellow sweet potato Makgeolli using the optimum mixture formulation produced higher soluble sugar content compared to others. Regular sweet potato Makgeolli produced higher pH. The purple sweet potato Makgeolli's total polyphenol content and DPPH radical scavenging activity were measured to be the highest at $771.91{\pm}1.42mg\;GAE/{\ell}$, $131.55{\pm}4.03%$.

• The Korean Journal of Food And Nutrition
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• v.27 no.1
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• pp.22-30
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• 2014

In this study, purple sweet potato bread was prepared by the addition of 0.005%, 0.010%, 0.015% and 0.020% hemicellulase. It's effect on product quality and consumer evaluation were examined. The results showed that the dough pH and total titratable acidity were not significantly different between samples. In the fermentation power of dough expansion, a 0.015% addition sample was the highest between the samples. The bread pH decreased significantly as hemicellulase was increased, whereas. Bread total titratable acidity was significantly decreased. The addition of hemicellulase samples were significantly higher in specific volume and baking loss than the control sample. The moisture content was not significantly different between samples. In colors, the lightness of the control sample was the highest, the redness of the 0.020% addition sample was the lowest while the yellowness of the control was the lowest. The hardness and the fracturability decreased significantly as hemicellulase was increased. The resilience indicated reverse effects. In consumer evaluation, the color and softness were not significantly different between samples. And the hemicellulase addition of samples was higher in flavor than that of the control sample. The overall acceptability was the highest at 5.67 with a 0.010% addition sample. According to these results, the addition of 0.010% hemicellulase in purple sweet potato bread would be the optimum level.