• Journal of the Korean Society of Food Culture
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• v.18 no.3
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• pp.202-210
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• 2003

The purpose of this study was to investigate the effects of dietary purple sweet potato(Ipomoea batatas) powder on serum lipid levels and antioxidative enzymes in normal and pretective effect on hepatotoxicity rats induced by carbon tetrachlolide. Four groups of rats (3-week-old inbred Sprague-Dawley male rats) were normal rats fed control diet(C), induced hepatotoxicity rats fed control diet(EC), normal rats fed purple sweet potato diet(P), and induced hepatotoxicity rats fed purple potato sweet diet(EP). Rats were induced by single injection of 50% carbon tetrachlolide(0.1 mL/100 g B.W., i.p.). The rats were fed ad libitum each of the experimental diet for 5 weeks. After 5 weeks the rats were sacrificed and activities of antioxidant enzymes and lipid peroxidation products were determined in their liver homogenates. But serum concentrations of lipid was not significant in all groups. Serum alanine aminotransferase(ALT/GPT) and aspartate aminotransferase(AST/GOT) of the EC and EP groups were heigher than the C and P groups. The hepatic glucose 6-phosphatase(G6Pase) activity of the group fed purple potato diet(P) was lower than the other groups(p<0.05). However, The glutathione peroxidase(GPx) activities was not statistically different between the groups. Renal glutathione S-transferase(GST) activity of the EC and EP groups were lower than the C and P groups(p<0.05). In conclusion, these results suggest that purple sweet potato is believed to be possible protective effect on hepatotoxicity rats induced by carbon tetrachlolide.

• The Korean Journal of Food And Nutrition
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• v.30 no.3
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• pp.491-500
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• 2017

Sweet potato-malt worts were prepared by using sweet potato paste of Shinyulmi and Shinjami as the main adjunct, enzymes, malt, hop, and water. We brewed low-malt beers of the lager- or ale-type by using these worts and inoculating bottom and top fermenting yeast, respectively. Moreover, the componential and functional characteristics of the resulting beers were evaluated. During saccharification of sweet potato, the addition of an enzyme agent containing ${\alpha}-amylase$ caused an improvement in filterability and an increase of total sugar. The sugar content of sweet potato-malt wort which was prepared by the addition of 0.1% enzyme agent containing ${\alpha}-amylase$ and a three-step infusion procedure was $13.5^{\circ}Brix$ adequate for beer brewing. The polyphenol and anthocyanin contents of Shinjami beer were increased with increasing content of the paste, and also increased DPPH and ABTS radical scavenging activities. But in Shinyulmi beer it were decreased. A strong correlation was obserbed between antioxidave activities and polyphenol and anthocyanin contents of sweet potato beers. In all lager- and ale-type low-malt beers using 41.6% of Shinjami pastes, sensory attributes very similar to those of 100% malt beer were obtained and they were very good as they had unique red color.

• Food Science and Preservation
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• v.24 no.2
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• pp.221-229
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• 2017

The effect of sweet potato on the quality of Doenjang was investigated during fermentation. Viable cells of yeast decreased gradually after 4 weeks of fermentation, but those of aerobic bacteria increased in the late stage. Amylase activity of Doenjang was higher in the late stage of fermentation, while neutral protease maintained high activity during fermentation. Hunter L and b values of Doenjang decreased gradually during fermentation, while a value was increased. The pH of Doenjang decreased gradually until 10 weeks of fermentation, and the titratable acidity was low in the sweet potato added groups. The acid value was low in the Shinyulmi sweet potato added Doenjang. Water activity and oxidation-reduction potential of Doenjang decreased during fermentation. Reducing sugar of Doenjang decreased in the middle stage of fermentation, and it was low in sweet potato added groups. The alcohol content of Doenjang decreased after 2 weeks of fermentation. Amino and ammonia-type nitrogen of Doenjang increased during fermentation and reached the maximum after 10 and 12 weeks of fermentation, respectively. After 12 weeks fermentation, 8% of Shinyulmi sweet potato added Doenjang was more favorable taste, flavor and overall acceptability (p<0.05) than the control or the Yeonwhangmi sweet potato added groups.

• Korean Journal of Food Science and Technology
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• v.10 no.3
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• pp.331-336
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• 1978

In an attempt to study the possibility of substituting sweet potato for cereals as raw materials for Kochujang, three kinds of Kochujang were made from barley, sweet potato or 50% barley and 50% sweet potato, The results of component variation during the ripening and the effect of temperature on the aging in the harvesting season of sweet potato were as follows: 1) Kochujang is, usually, manufactured in May, but no difference was observed in aging condition when it was manufactured in September, the season of sweet potato harvest, since the inner temperature of the product was around $20^{\circ}C$. 2) The total reducing sugar content and maturity reached maximum after $40{\sim}50\;days$ of fermentation in the three treatments and crude fat content tended to be slightly decreased during fermentation. 3) Lightness in color of the three kinds of Kochujang decreased by exposure to sunlight. Sweetpotato Kochujang showed a stronger tendency to increase the redness as compared with the rest. 4) Sensory evaluation showed that sweet potato Kochujang was less acceptable than barley Kochujang due to disagreeable flavor of sweet potato but mixed Kochujang showed little difference, as compared with barley Kochujang.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.147-152
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• 2011

The physical properties of puffed snack by pellet with sweet potato flour, brown rice flour and wheat flour were evaluated at different moisture content, puffing temperature, and puffing time. The sweet potato pellets were tempered to 14, 16, and 18% moisture content and were puffed at 233, 238, and $243^{\circ}C$ for 4, 5 and 6 s. The whitness ($L^*$) value decreased as the heating temperature and time increased. The redness ($a^*$) and yellowness ($b^*$) values increased with increasing heating temperature and time. The specific volume of sweet potato puffed snacks showed an increasing trend with higher puffing conditions. The hardness of sweet potato puffed snacks increased as heating time and heating temperature increased. The sweet potato puffed snacks prepared with increasing moisture content (18%), heating times (6 s), and heating temperatures ($243^{\circ}C$) were awarded the highest scores for most of the sensory attributes and hence declared as best sweet potato puffed snacks.

• Food Science and Preservation
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• v.18 no.5
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• pp.714-720
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• 2011

Sweet Pumpkin (Cucurbita maxima) is rich in minerals, vitamins, and dietary fibers and has less fat. It is thus effective for dieting and for preventing constipation. Sweet Pumpkin contains vitamin A, particularly beta-carotene, which is turned into retinol in the body and helps protect the vision. It is currently on the spotlight as a vision care, anticancer, and diet food, among others, but because it is hard to find yogurt made of Sweet Pumpkin, in this study, Sweet Pumpkin powder was added to yogurt for promotion as a new health food. Yogurt was made with 0, 0.5, 1, 2, and 3% Sweet Pumpkin powder, and the color properties (brightness, redness, and yellowness), viscosity, pH, and acidity were measured through a sensory test (color, flavor, taste, overall acceptability). The storage stability at five-day intervals for one day, five days, ten days, 15 days, etc. was also experimented on. For the color properties, the greater the amount of Sweet Pumpkin powder added, the greater the decrease in the lightness (L) value, but the redness (a) and yellowness (b) values increased (p<0.001). For the viscosity, it was decreased for five days and then increased by 47-68% for ten days. This showed a significant difference in storage stability period: one day (p<0.001), five days (p<0.01), and ten days (p<0.01) (except 15 days). Further, there was a significant difference in pH and acidity [pH: for one day (p<0.001), five days (p<0.01), and ten days (p<0.01); acidity: one day (p<0.001), ten days (p<0.05), 15 days (p<0.001)]. No significant difference in pH was shown, however, for 15 days, and in acidity for five days. The results of the sensory test are highly estimated in the order of 1%>2%.3%>0%>0.5%. The study results indicate that the addition of 1% Sweet Pumpkin powder is most suitable for manufacturing Sweet Pumpkin yogurt.

• 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.

• Journal of Applied Biological Chemistry
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• v.54 no.4
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• pp.303-308
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• 2011

To develop food and organoleptic quality of gochujang 0, 3, 4, and 5% of sweet persimmon powder were added to Korean traditional red pepper paste during fermentation and microbiological and organoleptic characteristics were investigated. The total bacteria count of the gochujang tended to increase slowly until a level of $10^8$ CFU/g with increasing fermentation time. There was no significant difference (p <0.05) between the control and the treatment during fermentation. The number of yeast and mold was $10^4-10^5$ CFU/g during fermentation. Sensory evaluation after 30, 60, and 90 days of fermentation showed that addition of sweet persimmon powder to the gochujang did not affect its color, but the level of sweetness and umami, increased as additional level of sweet persimmon powder increased. In the overall acceptabilty, there was no significant difference (p <0.05) until 30 days of fermentation and the gochujang added with 4% sweet persimmon powder showed the highest organoleptic value. And it showed high score in sweetness, umami and overall acceptability at the end of fermentation. The results indicated that 4% additional level of sweet persimmon powder was the best making gochujang.

• Applied Biological Chemistry
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• v.49 no.4
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• pp.309-314
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• 2006

This study was performed to confirm the physicochemical properties and physiological activities according to cultivar and parts of Ulsan sweet persimmons. The proximate composition of the sweet persimmons was moisture $77.68{\sim}84.65%$, crude ash $0.3{\sim}0.6$, crude fat $0.29{\sim}0.39$ and crude protein $0.52{\sim}0.61%$. Confirmed organic acids and free sugars in sweet persimmons were malic, citric, succinic, and fumaric acids, along with fructose, glucose and sucrose. The major fatty acids were linolenic, vaccenic and palmitic acids. Also, K is the highest mineral in sweet persimmons that accounts for the majority of mineral, more than 60% as $84.9{\sim}103.7mg%$. Contents of vitamin C, total phenolic compounds and flavonoids were the highest in Fuyu peel as 139.91, 169.36 and 60.79mg%, respectively, Electron donating ability and xanthine oxidase inhibition were the highest in Fuyu peel as $30.6{\sim}91.2$ and $26.3{\sim}91.9mg%$, respectively. Nitrite scavenging activity was higher in peel than flesh as $51.0{\sim}76.4mg%$ with slight difference depending on cultivar.