• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.24-29
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• 2002

The study was performed to investigate the degrees of gelatinization at various processing steps during the preparation of Dangmyuns using sweet potato, potato, corn and tapioca starches, and also determined the rehydration of the freeze dried sweet potato Dangmyun. The degrees of gelatinization after extrusion cooking showed higher value than other processing steps. The degrees of gelatinization after extrusion cooking were 63.5% in sweet potato, 80.0% in potato, 82.3% in corn, and 86.5% in tapioca Dangmyuns. The degree of gelatinization in Dangmyuns after extrusion cooking step decreased as the processing steps, such as cold storage, freezing, thawing, and sun drying, progressed. L values of color in Dangmyuns decreased in the order of corn>tapioca>potato>sweet potato Dangmyuns. The cooking loss decreased in the order of tapioca>corn>potato>sweet potato Dangmyuns. The percentage of weight gain was the highest in sweet potato Dangmyun followed by corn, potato, and tapioca Dangmyuns. The water absorption rate constant was the highest in sweet potato Dangmyun followed by corn, potato, and tapioca Dangmyuns. In the rehydration of freeze dried Dangmyuns, freeze dried sweet potato Dangmyun showed better than the others. An increase from 60% to 70% of the added amount of water in the mixing step resulted in an increase of the degrees of gelatinization after extrusion cooking from $63.4{\sim}70.7%$ to $73.8{\sim}75.0%$. An increase of the added water in the mixing step and a decrease of diameter in the extrusion cooking step slightly improved the rehydration in the boiled water of freeze dried sweet potato Dangmyun.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.4
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• pp.489-496
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• 2012

This research investigated the quality characteristics and anthocyanin content of wet noodles according to the amount of freeze-dried purple sweet potato powder. For viscosity, initial pasting temperature tended to increase compared to the control group, whereas peak viscosity, peak viscosity time and final viscosity steadily decreased. As the amount of purple sweet potato powder increased, breakdown value of viscosity and set back value significantly decreased. For chromaticity, as the amount of purple sweet potato powder increased, L-value decreased gradually, whereas a-value gradually increased and b-value significantly decreased compared to the control group. Anthocyanin content significantly increased in the addidtive group (91.79) compared to the control group (70.20). Measurement of texture characteristics found that hardness was highest in the control group, but it decreased as the amount of purple sweet potato powder increased. Springiness, gumminess and chewiness were highest in the control group. In the sensory evaluation, color, odor, chewiness, and overall acceptance were high in the 6% addictive group. In this study, by investigating the anthocyanin contents, quality characteristics and sensory attributes of wet noodles with freeze-dried purple sweet potato powder, we found that the 6% additive group is the best. Our results provide basic information for the development of noodles with purple sweet potato powder.

• Korean journal of food and cookery science
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• v.27 no.2
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• pp.73-81
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• 2011

Two kinds of steamed sweet potatoes were dried with mild hot air to improve quality, convenience and preference as a snack. Steamed sweet potatoes were dried at temperatures ranging from 35 to $65^{\circ}C$ for 12 hr, and moisture contents, colors, texture, and taste were evaluated. The lowest moisture content was 0.25% at $65^{\circ}C$. Color values (L, a, b and ${\Delta}E$) decreased with increasing drying temperature and drying time in both chestnut-sweet potatoes and pumpkin-sweet potatoes. Reducing sugars and soluble solids increased quickly at high drying temperatures. The highest hardness value for chestnut-sweet potatoes was $26.31\;kg_f /cm^2$when they were dried at $65^{\circ}C$ for 12 hrs. Springiness and cohesiveness were higher than those in chestnut-sweet potatoes. The highest taste score was for a dried chestnut-sweet potatoes at $55^{\circ}C$ for 6 hr and a dried pumpkin-sweet potatoes at 45 or $55^{\circ}C$ for 6 hr.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.477-484
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• 2017

This study was conducted to investigate the content of sulfur dioxide, carotenoids and the degree of contamination of Bacillus cereus in 33 kinds of dried sweet potato from domestic mainly dried agricultural products in Korea. According to the characteristics of dried sweet potato samples, it was classified into four clusters and as a result of analyzing the contents of sulfur dioxide, carotenoids and the degree of contamination B. cereus was no significant difference among the clusters. The detection ranges of residual sulfur dioxide from 33 dried sweet potatoes ranged from 0.38 to 28.16 mg/kg, three cases (9.09%) were detected at the reference level of 10 mg/kg or more. But no samples exceeding 30 mg/kg, the tolerance level of sulfur dioxide in dried sweet potatoes were detected. Since dried sweet potato does not have a standard for carotenoids, when comparing the national and international standards of carotenoids, the range of detection of carotenoids in dried sweet potato was $46{\sim}2,663{\mu}g$/100 g, which was within the reference range of $0{\sim}9,826{\mu}g$/100 g. In principle colonies suspected to be B. cereus in dried sweet potato were not detected. In 7 cases (21.21%), there were detected in the range of 0.05~1.59 log CFU/g but not more than 3 log CFU/g as the reference value. The results of this study are expected to be used as basic data to establish quality standard for dried sweet potatoes. In order to control the quality of dried sweet potatoes in domestic market, raw materials, drying method and packaging after distribution, it is necessary to maintain and maintain the process steadily.

• Food Science and Preservation
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• v.24 no.2
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• pp.246-253
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• 2017

This study was conducted prepare spray-dried powder using pumpkin sweet potato hydrolysates and examine the physicochemical properties of the powder. The insoluble dietary fiber and soluble dietary fiber of the pumpkin sweet potato treated by enzyme were 4.17% and 2.07%, respectively. The spray-dried pumpkin sweet potato hydrolysates was manufactured via spray-drying with different forming agents: i.e., pectin 0.1%, 0.5%, 1%, and 2.0%. The moisture contents and total starches of the spray-dried powders were approximately 1.68-2.46 and 45.32-46.51%, respectively. The color of the L and a value decreased, and that of the b and ${\Delta}E$ value increased. The particle size and outer topology of the spray-dried powders were $37.17-42.32{\mu}m$, and its shape was generally globular. The water absorption index of the spray-dried powder (1.74-1.91) was lower than that of the freeze-dried powder (2.15). The water solubility index of the spray-dried powder, 80.75-87.61%, was higher than that of the freeze-dried powder (70.47%). The adhesion values of spray-dried powder to epithelial HT-29 cells were 2.66-6.18% of the initial cell counts, whereas freeze-dried powder showed lower adhesive ability (1.79%). The in vitro human digestibility in the spray-dried powder was 70.09% which is very effective in digestion.

• Culinary science and hospitality research
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• v.18 no.5
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• pp.279-292
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• 2012

This study was performed to investigate the quality characteristics and antioxidant activity of noodle added freeze-dried purple sweet potato powder. For Hunter's color resulted, as the amount of purple sweet potato powder increased, L-value and b-value decreased, the a-value increased. Anthocyanin contents of purple sweet potato powder at concentration of (mg/100 g) were 99.62%. DPPH radical scavenging activities of purple swe et potato powder at concentration of $1,000{\mu}L/mL$ were 84.60%. The texture of cooked noodles appeared no significant differences in cohesiveness, Springiness, Hardness, Gumminess and Chewiness decreased as the am ount of purple sweet potato powder increased. The weight, volume, moisture contents of noodles were not significantly. Sensory evaluation of acceptability including color, aroma, taste, chewiness and overall-acceptabi lity appeared the 6% added group was the best for higher. According to the positively evaluated anthocyanin content, DPPH radical scavenging activities, quality characteristics and sensory evaluation, a purple sweet pota to powder content 6% appears to be most appropriate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.37-46
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• 2011

Polyphenolic content and antimutagenicity of the methanol extracts prepared from 22 cultivars of sweet potato with different flesh colors were investigated using Folin-Ciocalteu's phenol reagent method and Ames test, respectively. There was a remarkable cultivar difference in the polyphenolic content of sweet potato. Su, Hayanmi and Shinhwangmi among 17 cultivars of non-purple sweet potato had higher polyphenolic contents of 21.4, 21.5 and $20.3{\mu}g$ (GAE/g dried sweet potato), respectively, whereas Manami and Yeonhwangmi were very much lower at 4.6 and $4.8{\mu}g$. Mokpo No.62, Borami, Sinjami, Jami and Ayamurasaki had much higher polyphenolic contents of 67.7, 76.9, 44.9, 128.3 and $93.2{\mu}g$, respectively, than non-purple sweet potato. The methanol extract from the sweet potato effectively inhibited the reverse mutation induced by 1-NP, daunomycin, Trp-P-1, Trp-P-2 and 2-AA on S. Typhimurium TA 98, and by 1-NP on S. Typhimurium TA 100. These results suggest that the antimutagencity properties may be influenced by the tested mutagen and strain rather than the polyphenolic content of non-purple and purple sweet potato. However, in the purple sweet potatoes, a high polyphenolic content may influence the antimutagencity properties.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.569-576
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• 1993

A feeding trial was conducted to determine the effectivity of microbial treatment on eliminating the toxicity of weevil-infested sweet potato roots, and to assess intake level and performance of broilers fed microbiologically-treated, weevil-infested sweet potato meal. Weevil-infested sweet potato meal was treated with Aspergillus awamori (terpene-degrading fungus), dried, and mixed with other ingredients. One hundred twenty (120) broiler chicks were randomly distributed to treatment diets containing 3 types of sweet potato meal (healthy, weevil-infested, and microbiologically-treated, weevil-infested) incorporated at 2 levels (12% and 24%) in the ration, following the $2{\times}3$ factorial in CRD with 4 replicates per treatment. Voluntary intake was high with healthy sweet potato meal, even at 24% in the ration, especially at later stage of broiler development. Weevil infestation of sweet potato meal, even at 24% in the ration, especially at later stage of broiler development. Weevil infestation of sweet potato roots significantly reduced voluntary intake and broiler performance even at 12% level in the diet, much more at 24% level (p<0.01). Microbial treatment, however, was found to alleviate such problem, especially at 24% level of incorporation (p<0.01). "Toxicity" of weevil infestation, in terms of enlargement of liver and spleen, in the absence of mortality, was only apparent at 24% level of incorporation in the ration. Again, this was minimized by microbial treatment (p<0.01), and is therefore recommended at high levels of incorporating weevil-infested sweet potato meal in broiler diets. Microbial treatment constitutes an added cost, so that economic analyses should be done to find out whether increases in broiler performance, or reduction in the toxic effects of terpenoid compounds, outweigh the cost of treatment before a definite recommendation can be made for its commercial application.

• Korean Journal of Food Science and Technology
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• v.2 no.2
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• pp.1-7
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• 1970

1) A process was described for the preparation of drum-dried weaning food containing about 20% protein and based on a blend of sweet potato, full-fat soy flour, minerals, vitamins and methionine. 2) The protein efficiency ratio of this product was 2.63 as compared to 3.30 for the blend containing corn starch in place of sweet potato. This is attributed to the partial destruction of available lysine in the presence of sweet potato during the drum-drying process. 3) Overall nutritive value of the weaning food was comparable to milk food and control food based on corn starch and soy flour in terms of feed efficiency, body composition and protein retention.

• Journal of Chitin and Chitosan
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• v.22 no.2
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• pp.110-117
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• 2017

This study was conducted to examine the physicochemical properties and hot air-dried and spray-dried powders process of sweet potato and steamed sweet potato. The moisture and the total starch contents were 1.66~2.19% and 52.65~57.42%, respectively. The total starch contents increased during process steaming. The water absorption index of the spray-dried powders (0.97 and 2.03) was lower than that of the hot air-dried powders (2.12 and 4.71), and the water solubility index of the spray-dried powders (83.83 and 86.95%) was higher than that of the hot air-dried powders (68.40 and 81.21%). The particle size and outer topology of the spray-dried powders were 46.18 and $65.53{\mu}m$, and its shape was generally globular. In the DSC analysis of this study, the $T_o$ of the spray-dried powders (64.40 and $67.80^{\circ}C$), $T_p$ of the spray-dried powders (74.40 and $78.20^{\circ}C$), and $T_c$ of the spray-dried powders (81.10 and $81.60^{\circ}C$) was higher than that of the hot air-dried powders. The solubility contents of the spray-dried powders (68.21 and 80.73%) was lower than that of the hot air-dried powders, and the swelling power contents of the spray-dried powders (14.79 and 15.35%) was higher than that of the hot air-dried powders. The amylose contents of spray-dried powders (11.67 and 12.51%) was lower than that of the hot air-dried powders. The soluble dietary fiber contents of spray-dried powders (1.34 and 2.02%) was higher than that of the hot air-dried powders.