• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.4
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• pp.487-493
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• 2012

This study was performed to investigate the effects of a diet with a red yeast sweet potato supplement on fecal amount and lipid metabolism in male Sprague-Dawley rats fed a high-fat diet for 10 weeks. Rats were fed a high-fat diet (15% fat) with additional lard (7%) and cholesterol (1%) based on AIN-93G basal diet (7% fat) for 6 weeks during the first phase. In the second phase, which lasted 4 weeks, the rats divided into four experimental groups which were composed of a high-fat diet group as a control (CON), a high-fat diet with 5% white-fleshed sweet potato supplement group (WFSP), a high-fat diet with 5% red yeast sweet potato supplement group (RYSP), and a high-fat diet with 5% purple-fleshed sweet potato supplement group (PFSP). The fecal amount of group RYSP increased significantly during the second phase compared to the other groups (p<0.05). The fecal total cholesterol (TC) and triglyceride (TG) content of group RYSP were also highest among all experimental groups. The serum TC and TG were shown to have the lowest levels in the group RYSP, and LDL-cholesterol levels were significantly decreased in groups RYSP and PFSP than in group CON (p<0.05). These results indicate that supplementation with red yeast sweet potato seemed to be effective in increasing feces and fecal lipid excretion, and also in decreasing serum lipid levels in rats fed a high-fat diet.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.666-671
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• 1993

Mixtures (total solid content: 15%) prepared with whole milk added with skim milk powder and/or sweet potato and/or pumpkin were fermented with 0.205% gelatin, 2% sugar and yogurt bacteria. The fermented mixtures (curd yogurt) were evaluated for acid production (pH, titratable acidity), number of viable cell, sensory property and keeping quality. The acid production of all mixtures remarkably increased for the first 12 hours and there is no significant difference among the mixtures. The lactic acid bacteria counts in the all products after 24 hours incubation were above $6.4{\times}10^{9}cfu/ml$. In organic acids, the mixture added with skim milk powder was higher ratio of lactic acid content to total acidity than those added with sweet potato and/or pumpkin. The sensory score of mixture containing sweet potato was best but curd yogurt containing pumpkin reduced the sensory property. When each mixtures were kept at $5^{\circ}C$ for 15 days, pH, titratable acidity, and number of viable tells of yogurt were not changed.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.702-712
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• 2020

Synthetic nitrite imparts a reddish-pink color to meat and a distinct flavor to meat products, delays lipid oxidation, and inhibits microbial growth and pathogens. However, excessive intake of nitrite might result in the production of carcinogenic nitrosamine, which might increase the risk of cancer in humans. Therefore, we aimed to find an alternative natural colorant for pork sausages. Pork sausages were mixed with 0.014% sodium nitrite (NaNO₂) alone (CON), without either NaNO₂ or purple-fleshed sweet potato powder (PP; CON1), 0.5% PP alone (PP1), 1% PP (PP2) alone, 0.011% NaNO₂ and 0.5% PP (SP1), and 0.011% NaNO₂ and 1% PP (SP2). The sausages were then cooked and stored for physicochemical analysis on days 0, 5, 10, 15, and 20. The a* and W* values were the greatest and lowest in the SP2 and CON1 treatments, respectively (p < 0.05). The concentrations of residual nitrite in the sausages at 20 days decreased in the order of CON > SP1, SP2 > PP2 > PP1, CON1. The fatty acid content was higher, and flavorous amino acids were more in PP2 (p < 0.05). The fatty acid composition was comparable between the SP2 and CON groups, but the contents of glutamic acid and alanine were greater in the SP2 group. In conclusion, SP2 (0.011% NaNO₂ with 1% PP) could be added as a natural colorant for pork sausage production, and NaNO₂ could be substituted with up to 20% PP without detrimental effects on sausage appearance and/or quality.

• 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 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.339-346
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• 2008

The contents of starch, moisture, crude protein, crude fat, crude fiber, and ash of different varieties of various crops such as brown rice, barley, corn, sweet potato were analyzed. The average starch contents of brown rice, barley, corn, and sweet potato were $70.1{\pm}0.4\;{\sim}\;72.2{\pm}2.1$, $68.7{\pm}0.2\;{\sim}\;71.4{\pm}1.2$, $67.6{\pm}0.8\;{\sim}\;69.4{\pm}1.8$, and $21.7{\pm}0.9\;{\sim}\;28.3{\pm}0.5%$, respectively. The ground powder of each starchy substrate was suspended in distilled water, and then liquefied, saccharified, and fermented by dried active yeast at 32 for 4 days. By statistical analysis, the effectiveness of the contents of the different components such as starch, moisture, crude protein, crude fat, crude fiber, and ash of the crops on the ethanol production were examined. The results showed that the starch content positively affected the ethanol production in all the tested cereals and sweet potato. In brown rice, ash content affected negatively the ethanol production. In barley, protein content affected negatively the ethanol production, while fiber content affected positively the ethanol production. The sweet potato containing higher content of moisture produced less amount of ethanol.

• Korean Journal of Food Science and Technology
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• v.45 no.1
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• pp.40-46
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• 2013

The present study was performed to increase the availability of sweet (Ipomoea batatas) and to develop dinner roll with the reducing ability of blood glucose levels. Different contents of lyophilized sweet potato powder (SPP) were added in dinner roll. Compare to the control group, batter density, a value, hardness, and cohesiveness of the SPP-treated groups were significantly increased while dough expansion rate, baking loss rate, L value, and Hue angle were significantly decreased. Twenty four Sprague-Dawley rats were administered with the SPP-treated diet for 4 weeks after diabetes was induced with the injection of streptozotocin. The blood glucose concentration of the SPP-treated group was significantly lower than that of the control. Although the SPP-treated groups possessed the ability of reducing blood glucose level, the sensory qualities were inferior to the control. Thus, follow-up study was required to improve the sensory characteristics as well as the texture properties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.403-409
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• 1989

Dietary fiber(DF) content and their properties were analyzed in some common vegetables such as Squash(leaf), Water cress, Garland chrysanthemum, Leek and sweet potato(stem). DF was analyzed by the method of detergent fractionation. Values for neutral detergent fiber(NDF), acid detergent fiber(ADF), lignin, hemicellulose were obtained. NDF for most samples was $13.83%{\sim}24.31%$, ADF was $11.99%{\sim}21.03%$, lignin was around $0.56%{\sim}3.00%$, hemicellulose was about $1.33%{\sim}3.88%$, cellulose was $9.08%{\sim}14.87%$ except sweet potato(leaf) (20.47%). This paper describes two properties of the fiber-of commonly eaten vegetables ; water-holding capacity(WHC) and metal binding. The capacity of the acetone dried powder (ADP) to hold water was estimated. The WHC measurements differed from 7.49 per 9 of ADP for Water cress to 11.09 per 9 of ADP for Leek. The binding of Fe, Zn in NDF. ADF obtained from five fiber sources was examined under two pH conditions ; 1) pH2.1, 2) pH6.1. Fe, Zn binding increased with higher pH and differed from DF sources.

• Korean journal of food and cookery science
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• v.22 no.2 s.92
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• pp.105-110
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• 2006

This study was performed to determine the sensory evaluation and mechanical characteristics of lemon red ginseng-pyun. Lemon red ginseng-pyun was made with lemon juice(21.4%), sweet potato starch(6.7%), water(53.3%), sugar(13.3%), honey(5.3%) and various concentrations of red ginseng powder(0, 2, 4, 6, 8, 10%). The quality characteristics of the sample were estimated in terms of pH, color difference, texture profile analysis and sensory evaluation. The pH of lemon red ginseng-pyun showed no significant difference among the different ratios of red ginseng. With increasing red ginseng powder addition, the lightness was significantly(p<0.05) lower, and a value and b values were significantly(p<0.05) higher. In sensory evaluation, with increasing red ginseng powder addition, the color and bitter taste of lemon red ginseng-pyun were stronger, while clarity of the 10% added red ginseng was significantly(p<0.05) lower than that of the 0% added red ginseng. Elasticity, hardness, chewiness, softness. sweet taste and overall acceptability were not significantly different in any group. In texture profile analysis, chewiness, cohesiveness, gumminess and hardness were significantly(p<0.05) increased in the 10% added red ginseng but springiness was not significantly different in any group. Overall acceptability was related to texture, appearance, overall taste and sweet taste of lemon red ginseng-pyun. Therefore, development of lemon red ginseng-pyun with no sugar or artificial sweeteners is encouraged as a healthy diet for diabetes and hypertension patients, because red ginseng is defined as a functional foods.

• 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%.