• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.9
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• pp.1314-1320
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• 2011

Vacuum drying was conducted for a steamed pumpkin-sweet potato slab to improve its quality, convenience and preference as snack. Steamed sweet potato was dried from 30 to $60^{\circ}C$ for 12 hr, after which moisture contents, colors, and taste were evaluated. The lowest moisture content was 0.22% upon vacuum drying at $60^{\circ}C$ for 12 hr. Lightness decreased while other color values (a, b and ${\Delta}E$) increased with increasing drying temperature and drying time. Reducing sugar and soluble solid contents ranged from 98.7~268.11 mg/g and $19{\sim}72^{\circ}Brix$, respectively. Sensory score of the sample was the highest when dried at $50^{\circ}C$ for 6 hr. The optimum drying conditions were predicted to be $48.5{\sim}62^{\circ}C$ and 5.1~7.1 hr by response surface methodology.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.7
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• pp.994-1002
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• 2001

In a balance experiment with rats either 0, 25 or 50% of the crude protein (CP) provided as casein in the control diet was replaced with cassava leaves (CL) (Manihot esculenta Crantz) or sweet potato vines (SPV) (Ipomoea balala). CL were either sun-dried or oven-dried at $60^{\circ}C$ or $105^{\circ}C$ or ensiled, while the SPY were either sun-dried or ensiled. The experiment included 3 blocks with 30 rats in each and six individuals per treatment group. Drying at $105^{\circ}C$ resulted in a reduction of the lysine (Lys) content, suggestive of the occurrence of Maillard reactions. Ensiling CL and SPV slightly decreased the CP. content as well as the sum of essential amino acids. The apparent fecal CP digestibility (dCP) and nitrogen retention were negatively affected by increasing the level of replacement (p<0.01 and p<0.001, respectively). The impaired amino acid profile observed when drying CL at $105^{\circ}C$ was found to be related to a slight decrease in dCP (p<0.001) as well as N retention (p<0.005). The effects of sun-drying and oven-drying in reducing the HCN content in CL were more potent than when ensiling. By increasing the total dietary HCN supply serum thiocyanide level, as well as urinary thiocyanate and linamarin output, were increased, with a weak relationship between them. Sun-drying and ensiling with cane molasses as additive successfully preserved the nitrogenous constituents and could be a means of preserving fresh green feed under tropical conditions.

• 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.26 no.6
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• pp.805-813
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• 1994

Zucchini slices, sweet potato stems, taro stems, and platycodon treated with various methods such as dipping in citric acid solution, sulfite solution, or sulfur fumigation were dried by the natural sun drying method or the forced air drying method at 50, 70, 90, or $105^{\circ}C$. Mold growth of the dried vegetables and sensory quality of the dried and rehydrated vegetables were investigated. Limiting moisture contents to prevent mold growth over 3 month storage under room temperature were 15, 20, 25, and 15% for zucchini slices, sweet potato stems, taro stems, and platycodon, respectively. The chlorophyll containing vegetables dehydrated by the forced hot air showed better sensory quality than those by the natural sun. Among the pretreatments, dipping in the sulfite solution provided the best sensory quality to the dried vegetables. The sensory quality of dried platycodon was improved to a small extent by sulfur fumigation and sulfite solution treatment. The sensory quality of the dried platycodon was not found to be affected by the drying methods. All the tested vegetables dried at $105^{\circ}C$ had the worst sensory quality. Except drying temperature of $105^{\circ}C$, the lower the drying temperature, the better the sensory quality and the rehydration rates were obtained for the tested vegetables except platycodon. The sensory quality of the platycodon was little affected by the drying temperature tested in the range of $50{\sim}90^{\circ}C$.

• 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.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.235-246
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• 2001

The survey on the practice of the memorial ceremonial food in Chuncheon area showed it varied according to social position of officiator, location(inland or seaside town) , and personal condition. The study included the foods prepared for the memorial services on the memorial day. New Year's Day and Chusok. 1. 40.4% of the subjects were in the thirties at their age, 46.6% were high school graduates, 57.3% were the first daughter-in-law, 40.4% had no religion, 30.9% were working at public administration and earned less than 1 to 1,5 million won monthly. 2. 71.7% of the subjects who replied that the ancestor worship service had to be kept were Buddhists. 55.4% of them were high school graduates, and 58.8% of them ran independent businesses. They learned how to practice the ancestor worship service from their mother before marriage or from their parents-in-law after marriage. 3. The older the officiators, the better they wanted to keep the traditional format of the service, but the Christians and Catholics wanted to change the format to western style in the future. 4. 92.7% of them served cooked milled rice. They prepared the soup in the order of beef soup, radish soup and dried Alaskan pollack soup. 5. Among cooked vegetable dishes, bracken was used the most and balloonflower root, mung bean sprout and spinach followed. Among jeon(pan-fried foods). frozen Alaskan pollack was used the most and buckwheat, mung bean and meatball followed. 6. They served san-juk(beef kebab) mostly on the ceremony. Among the grilled foods, tofu was the favorite, and croaker followed. 7. Among the fried foods. squid was the favorite, and sweet-potato and shrimp followed. Among the dried foods. they used in the order of dried Alaskan pollack, dried beef and squid. 8. Among the rice cake and traditional confectionery, they used in the order of Yak-sik(sweet rice cake), Gang-jeong(fried glutinous rice cookie), Jeol-pyun and In-jeol-mee. Among a beverage, they served Sik-hye(fermented rice drink) mostly. 9. Among fruits, apples. jujube, chestnut and dried persimmon were served. Aong a liquor, Cheongju was served mostly. 10. Soy sauce, salt and salted fermented fish were served, too.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.95-100
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• 1982

Torulopsis candida FRI YA-15, a selected yeast, was cultivated in alcohol distiller's waste-filtrate of dried sweet potato for microbial protein production and BOD reduction. The General composition of waste-filterate was BOD$_{5}$ 15700 ppm, COD 36800 ppm, reducing sugar 3300 ppm, total nitrogen 910 ppm, total solids 51800 ppm and ash 390 ppm. The pH of waste was 3.85. The yield to the medium of T. candida cultivated in shake-flask at $25^{\circ}C$ for 48 hrs was 3.38g/$\ell$ and effectiveness in reducing BOD$_{5}$ and COD of waste was 38.9% and 31.8%, respectively. In batch cultivation using 3 $\ell$-jar fermenter, maximum yield to the medium reached 3.2g/$\ell$after 28 hrs cultivation under the condition of temperature 35$^{\circ}C$, initial pH 4.0, aeration rate 2vvm, agitation speed 100rpm. Dry yeast was composed of crude protein 47.98% and ash 5.23%.

• Journal of Nutrition and Health
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• v.9 no.1
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• pp.60-68
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• 1976

A group of 132 pre-school children with a mean age of six years and one month was the subjects of this investigation. These children were members of three nursery schools locating in Kwang-ju city. Each child's mother replied to a questionaire which included 42 food items and 4 questions. The results showed that the food preference of each child was variable and the group as a whole expressed more positive than negative feelings. The average number of foods liked per child was 22.9(range: $7{\sim}42$) among 42 food items. Peach, Apple, Strawberry, Laver, Egg, Tomato, Sweet Potato, Tangerine Orange and Beef were ranked in descending order of 'like' ratings. The average number of foods refused was 4.9 (range: $0{\sim}25$). Onion, Liver, Red Pepper Leaf, Root of Bellflower, Taro, Wild Seasame Leaf, Egg Plant, Cabbage, Water Cress and Bracken were ranked in descending order of 'refuse' ratings. The odor of hurting feelings, the hot taste and the flabby texture were the reasons why the children refused these foods. The average number of foods unexperienced was 4.4 (range: $0{\sim}14$). Kidney, Dried Small Whitebail, Tangle (DA SHI MA), Liver, SA RI Mushroom, Acorn Mook, Dried Fragrant Mushroom, Pine Agaric, Root of Bellflower and Ped Pepper Leaf were ranked in descending order of 'unexperience' ratings. Children's 'like' rating toward total foods was 57.3% and the 'refuse' rating was 11.7%. Among eight food groups, fruits showed the highest favority (91.4%) and mushroom showed the least (25.9%). The difference between male and female in the preference of total foods did not showed significant level. But the difference were significant in those of individual food groups; other vegetables, green and yellow leafy vegetables, mushrooms(above, p.<01), fishes and shellfish and sea weeds (above, p<.05). Children who had experienced meals missed rated 59.1% and 34.1% of these children missed meals once a week. The main reason for maels missed was due to the heavey snacks before meal time. Children who had snacks twice a day rated 45.6%. Main foods used as their snacks were starch foods (Cake, Biscuit, Sweet Potato) and citrous foods (Fruits, Apple, Tangerine).

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.187-193
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• 1975

A supplemental effect of Undaria Pinnatifida extract on the composite flour prepared from a blend of wheat, barley, sweet potato, potato, and defatted soybean flours was studied in terms of binding properties, cooking test, and sensory analysis. Dry noodle of the composite flour was made by the conventional method and air dried. Instant noodle was prepared in a hot vegetable oil bath after the noodle was made. The standard was made of wheat flour only. 1. The noodle prepared with composite flour (wheat flour : barley flour, 5 : 5) and Undaria Pinnatifida extract (1 or 2%) showed same results of cooking and sensory tests as well as properties of texture as the standard. 2. The mixture of wheat, barley and defatted soybean flour (10%) had a less efficient binding capacity with Undaria Pinnatifida extract. The binding effect was, however, significantly improved with the wheat and barley flour mixture with either sweet potato or potato flour. 3. The instant noodle prepared with the composite flour (either barley, or sweet potato, or potato was mixed with wheat flour up to 70% separately) and hydroxypropyl methyl cellulose (1% as final) showed the higher oil absorption and the sensory results were the same as the standard. Nevertheless, the binding properties and cooking quality were less efficient.

• Food Engineering Progress
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• v.21 no.1
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• pp.42-48
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• 2017

The purpose of this study was to verify the drying characteristics of steamed sweet potato and to establish optimal drying conditions for far-infrared drying of steamed sweet potato. 4 kg of steamed sweet potato was sliced to thicknesses of 8 and 10 mm, and dried by a far-infrared dryer until a final moisture content of $25{\pm}0.5%$. The far-infrared dryer conditions were an air velocity of 0.6, 0.8 m/s and drying temperature of 60, 70, and $80^{\circ}C$. The results can be summarized as follows. The drying time tended to be reduced as temperature and air velocity for drying increased. The Lewis and Modified Wang and Singh models were found to be suitable for drying of steamed sweet potato by a far-infrared dryer. The color difference was 35.09 on the following conditions: Thickness of 8 mm, temperature of $80^{\circ}C$, and air velocity of 0.8 m/s. The highest sugar content ($59.11^{\circ}Brix$) was observed on the conditions of a thickness of 8 mm, temperature of 80, and air velocity of 0.8 m/s. Energy consumption decreased on the conditions of higher temperature, slower air velocity, and thinner steamed sweet potato.