• 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 $771.91{\pm}1.42mg\;GAE/{\ell}$, $131.55{\pm}4.03%$.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.1
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• pp.3677-3684
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• 1975

A newly devised dryer with heated air for the farm products, especially suited for high water content materials such as red pepper, Beer ground, each Vegetables, and Low water content materials such as Rough rice was tested for its thermal efficiency and drying mechanism, and the optimum conditions for each sample were established. In order to improve the present rural situation of drying farm products which entirely dependent upon natural solar radiation, a study upon an economic multi-parpose dryer was conducted. A series of drying tests were run first with red pepper which is one of the important cash crop in Korean farm. And successive series of tests were also run with such proaucts as garlic, sweet potatoes, green onion, radish, Beer ground and Rough rice. The results from the above experiment in drying system with heat dryer can be summarized as follows. 1. Drying duration could be shortened by the tempering effect in high water content crop such as red pepper and beer ground. 2. The color changes occured in around 20% water content in red pepper. The degree of color change was heavily affected by high temperature and short drying duration. 3. The drying condition of red pepper was most favourable at the temperature of 85$^{\circ}C$ in early stage and 80$^{\circ}C$ in middle stage and 75$^{\circ}C$ at the final stage, and with the air rate of 0.81㎥/sec and with sample amount of 200kg. 4. The drying condition of Rough rice(I.R.667) was most favourable at the templature of 40$^{\circ}C$ in early stage and 35$^{\circ}C$ in middle stage and final stage and with the air rate of 0.2㎥/sec and with sample amount of 75kg. 5. In order to prevent the color change of red pepper and to assure high efficiency in drying mechanism, it was necessary to lower the temperature as the time passes in drying process. 6. For vege tables, the drying rate were short in early stage and there was also tempering effect. However, for garlics, Constant drying rates through the early and final stages were observed and there were no tempering effects. 7. The drying condition or capability were as follows; Sample drying temp($^{\circ}C$) amount of material(kg) drying time(hr) Red pepper 85 200 9 Garlic 85 150 7 Sweet potato 85 200 6 Green Onion 85 200 4 Carrot 85 200 4 Radish 90 250 4 Rough rice(I.R.667) 35 75 4 Beer ground 90 320 3 Considering the above result of experiments, if this kind of dryers were distributed Korean farm and the optimun process were practiced in rural area, it would certainly help them improving the qualites of their product preventing their undue losses, and thus assuring an increase of Korean farm income and promotion of their living standards.

• Journal of Plant Biotechnology
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• v.7 no.3
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• pp.183-186
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• 2005

Cryopreservation has been recognized as a practical and efficient tool for the long-term storage of vegetatively propagated plants. This study was conducted to investigate the effects of slow-freezing techniques on the cryopreservation of potato. In vitro plantlets of the potato genotypes of 'Atlantic', 'Superior’, 'Namseo', 'J138', and 'CTO5-5' were cold acclimated, and the excised axillary buds were precultured, osmoprotected, exposed to plant vitrification solution, frozen slowly to $-40^{\circ}C$ and then rapidly plunged into liquid nitrogen, thawed and finally plated on the regeneration medium. It was found that the higher the sucrose concentrations in the subculture medium of donor plantlets, the higher the survival rates of shoot tips after cryopreservation, and the highest survival (20%) was observed in the medium added with 0.25 M sucrose. As for the effect of cooling, $0.3^{\circ}C/min$ cooling speed showed the highest survival (25%). Different varieties showed different responses over different cryopreservation treatments. Survival rate was increased by slow-freezing technique method as compared with that of the basic cryopreservation method of vitrification alone in the diverse potato genotypes. Leaf and tuber morphologies of potatoes regenerated after cryopreservation using slow freezing technique were similar to those derived from the in vitro stock plantlets.

• The Journal of Korean Society for School & Community Health Education
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• v.12 no.1
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• pp.59-70
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• 2011

Methods: This study was performed to estimate the use of frozen convenience food in middle schools located in the Daegu district. Objectives: These schools have directly managed school meal services. The subjects for this study were 145 students and 66 dieticians. The study involved a survey on food preference and quantity satisfaction of the students and the frequency of use of frozen convenience food in the daily menu. Results: As the result, 50.0% of the students were not satisfied with the meat and poultry quantity from school meals(felt small), and 25.0% of students were not satisfied with vegetables(felt much). The majority of students (50.7%) who were not satisfied with vegetables said they were dissatisfied with the school food because of the taste. On the other hand, 36.6% said they were dissatisfied because they dislike vegetables in general. As for the use and frequency rate of frozen convenience food, the survey results were revealed in the order of dumpling 58.3% > processed meat 50.0% > chicken 50.0% > frozen marine food 40.4% > cuttlefish 30.3% > miscellaneous 26.3% > vegetable & potatoes 14.4%. It was found that many schools employing more than five workers did not use flour-based frozen foods in their menu. As for the use of the frozen processed food, many schools which had an average food cost of more than 1,700 Won were found to use frozen foods more than once a month. In addition, chicken was not used often at the schools whose average food cost was less than 1,500 Won while many schools, whose average food items cost was more than 1,500 Won, incorporated chicken into the menu once a month. Processed flour food [hot dog] was used often by schools whose average food cost was between 1,500 Won and 1,600 Won. As for the actual conditions of using frozen convenience food, there was a significant difference in the use of chicken in relation with the number of food service recipients. As a result, the use of frozen convenience food has been shown to be related with food cost, number of food preparers, and the number of school students.

• Korean Journal of Community Nutrition
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• v.22 no.2
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• pp.159-170
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• 2017

Objectives: The purpose of this study was to estimate the distribution and exposure prevalence of total carbohydrate intake and the carbohydrate-based foods such as rice, noodles, sweet potatoes, sweet drinks, milk and fruits and to characterize intake patterns among obese Korean adults. Methods: Subjects included 137,363 adults aged 40 years or older who participated in a Health Examinees (HEXA) Study. Multiple regression analysis of data from Semi-Quantitative Food Frequency Questionnaire (SQFFQ) identified food sources of carbohydrates. Weight, height and waist circumstance (WC) were measured, and the body mass index (BMI) was calculated. Obesity was defined as $BMI{\geq}25kg/m^2$ and abdominal obesity as $WC{\geq}90cm$ and ${\geq}85cm$ for males and females, respectively. Results: Obese adults appeared to have a higher total carbohydrate intake in the univariate analysis but had eaten less after adjustment for general and lifestyle factors, compared to normal weight adults (OR 0.78, 95% CI 0.73-0.82 for general obesity; OR 0.79, 95% CI 0.74-0.85, for abdominal obesity; P trend < 0.0001, respectively). Based on advance analysis for the food sources of carbohydrates, obese subjects had lower intake of rice (OR 0.86, 95% CI 0.68 -1.09 for general obesity; OR 0.87, 95% CI 0.67-1.13, for abdominal obesity; P trend < 0.0001, respectively) and higher intake of noodles (OR 1.21, 95% CI 1.16-1.27 for general obesity; OR 1.25, 95% CI 1.19-1.32, for abdominal obesity; P trend < 0.0001 respectively). With regard to other food sources of carbohydrates such as milk and fruits, intake was lower among obese compared to normal weight subjects. Conclusions: In the Korean middle-aged and older obesity groups, the intake of carbohydrates and the related foods was lower than in normal weight subjects, except for noodles. We conclude that a higher intake of noodles may enhance weight-gain. Therefore, this study suggested that the guidelines should consider the types of carbohydrate sources and the amount consumed from foods in order to provide proper guidance with regard to control and prevent obesity among Korean adults.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.164-169
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• 2012

BACKGROUND: This study was conducted to monitor the residue of pesticides and to assess their risk in domestic agricultural products, such as fruit vegetables, tomatoes, oriental melons and root vegetables, garlic, potatoes and onions. METHODS AND RESULTS: 250 samples containing both general and environment-friendly certified agricultural products were collected from traditional markets and supermarkets in 6 cities. 132 pesticides except for herbicides were analysed using the multi-residue methods by GC/ECD, GC/NPD and HPLC/UVD. 17 kinds of pesticides were detected from 42 samples, which were 32 general, 1 organic, 4 pesticide-free and 5 low pesticide agricultural products. Among those, myclobutanil detected in 1 potato and procymidone detected in 10 oriental melons were unregistered pesticides for using in Korea. Fenbuconazole detected in 1 potato and phorate detected in 1 tomato were exceeded over the MRLs established by Korea Food and Drug Administration. CONCLUSION: Based on these results, a risk assesment was conducted using a percentage of acceptable daily intake(%ADI). %ADI ranged from 0.0064% to 4.6035%, and showed these values have no effect on human health.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.241-248
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• 2017

Yield of potato is largely influenced by drought stress. This study was conducted in Gangneung and Cheongju during the spring cropping of potato. Potatoes in the Gangneung area were affected by drought but there was no damage due to drought in Cheongju. During the early-growth stage, the contents of inorganic components like available phosphate and growth characteristics of the potato leaf in Cheongju were significantly higher than those in Gangneung but there was no difference after the flowering stage. It was considered that the potato plants cultivated in Cheongju could vigorously grow than that of Gangneung under drought stress. In addition, the content of calcium (Ca), which is a secondary messenger related to aging, was found to be higher in potato plants grown in Cheongju than in Gangneung and accumulated more quickly in potato plants of Cheongju. Because magnesium (Mg) was also found to be higher in potato plants from Gangneung by a wide margin, this phenomenon was thought be related with drought stress. The amounts of all inorganic components absorbed from soil were higher in Cheongju than in Gangneung, showing a relatively higher plant biomass in Cheongju. Correlations of development indexes related to leaf showed less or no relation in Gangneung. According to yield characteristics of the harvest stage, although yield was greatly reduced under drought stress condition, the rate of commercial yield was not significantly affected under the drought stress condition. Consequently, it was considered that these responses to drought stress could be utilized to stabilize potato production under the stressful conditions associated with abnormal climate.

• Korean journal of food and cookery science
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• v.24 no.4
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• pp.501-510
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• 2008

In this study, we evaluated the quality characteristics of sweet potato Sulgidduk produced with varying amounts of fresh sweet potato, after three days of storage. The more fresh sweet potato was added, the higher were the levels of crude protein and crude lipid; however, crude ash contents were lowest in the control sample, and no significant differences in this value were detected among the samples to which fresh sweet potatoes were added. Moisture contents evidenced a tendency to decrease with increases in the amount of added fresh sweet potato and increased storage time, but pH rose with increases in the amount of added sweet potato. Total cell counts showed a tendency toward decrease with increases in the amount of added fresh sweet potato. L values tended to be low with increases in the amount of added fresh sweet potato and a values were lowest immediately after its production, although no consistent tendencies were noted in correlation with the amount of added fresh sweet potato. b values tended to increase directly with the amount of added sweet potato . With increasing storage time, the L and a values decreased, whereas the b value tended to increase. Upon textural assessment, it was observed that hardness, adhesiveness, springiness, gumminess, and chewiness(all textural components except for cohesiveness) increased with increasing quantities of added fresh sweet potato, and these factors also tended to increase with the progression of storage time. After observation via scanning electron microscopy(SEM), it was noted that the cohesiveness also increased with increasing amounts of added sweet potato. With regard to the sensory evaluation, the samples to which 15% fresh sweet potato had been added evidenced the highest acceptability in terms of color, flavor, and s0weetness, and softness and moistness in these samples decreased with increasing percentages of added sweet potato. It has been previously demonstrated that the addition of 15% fresh sweet potato resulted in optimal overall acceptability. In accordance with the aforementioned results, it has been verified that the use of fresh sweet potato in Sulgidduk is possible and probably desirable, and an addition of 15% sweet potato appears to be the optimal approach in terms of overall quality and functionality.

• Journal of Life Science
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• v.20 no.11
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• pp.1569-1576
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• 2010

Sweet potato (Ipomoea batatas L.) is widely used in Indonesia and other countries as a traditional medicine for the treatment of diabetes mellitus (DM). The MeOH extract of white skinned sweet potatoes (WSSP) was administered orally in doses of 100 and 200 mg/kg body weight in streptozotocin (STZ)-induced diabetic rats. Experimental diabetes was induced by a single dose of STZ (45 mg/kg, i.p.) injection. Oxidative stress was measured by tissue lipid peroxide (LPO) levels, serum aspartate transaminase (AST), alanine transaminase (ALT), total triglyceride (TG), total cholesterol (TC) and by antioxidative enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase in the liver. An increase in blood glucose, LPO level, AST, ALT, TG and TC levels was observed in the STZ-induced diabetic rats. Administration of MeOH extract of WSSP at a dose of 200 mg/kg for two weeks caused a significant reduction in blood glucose, LPO levels, AST, ALT, TG and TC levels in the STZ-induced diabetic rats. Furthermore, oral administration of MeOH extract showed significant improvement in the activities of antioxidant enzymes (SOD, GPx, and CAT) compared to STZ-induced diabetic rats. In conclusion, the obtained results clearly indicate the role of oxidative stress in the induction of diabetes, and that the protective effects of MeOH extracts of WSSP could be used to benefit diabetic patients.