• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.169-175
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• 2006

Potentiometric biosensor using flow injection analysis system was developed to determine citrate concentration in foods. Biosensor system consisted of sample injector, peristaltic pump, enzyme reactor, carbonate ion selective solid-state electrode, reference electrode, detector, and recorder. Enzyme reactor was prepared with immobilized citrate lyase and oxaloacetate decarboxylase. Carbonate ions produced through enzyme reactions of citrate were potentiometrically detected by ion selective electrode. Optimum conditions for biosensor system were investigated. Interference effect of major sugars and organic acids was less than 5% on citrate biosensor system. Citrate concentrations in fruit juices were determined by biosensor and gas chromatography. No significant difference was observed between two analytical methods. Results indicate citrate biosensor is useful in determining citrate concentration in foods.

• Food Science and Industry
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• v.53 no.3
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• pp.284-294
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• 2020

High voltage pulsed electric field technology has been attracting attention in the the food industry as an eco-friendly nonthermal process technology using electrical energy. The lack of understanding of the equipment and the burden of equipment cost have not significantly increased the commercial application, but the potential as a technology to replace the heat process has been continuously increased. Sterilization of foods using the PEF process has been applied to liquid foods with low viscosity such as fruit and vegetable juices, but recently, high viscosity smoothies, high concentrate protein drink, mixed juice, and alcoholic beverages. Studies on sterilization of solid foods such as powders, raw meats are also being conducted. Also, the application of extraction and recovery of useful ingredients, activation of active compounds, pretreatment of drying, improvement of meat quality, changes of properties of starch has been studies.

• Nutrition Research and Practice
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• v.18 no.5
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• pp.674-686
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• 2024

BACKGROUND/OBJECTIVES: Mukbang, a trend originating in South Korea and gaining global popularity, could influence children's food choices and eating habits. This study analyzed the correlation between Mukbang viewing time in children and adolescents, their meal consumption frequency, nutrition quotient (NQ), and frequency of food intake. SUBJECTS/METHODS: From July to August 2022, this cross-sectional study investigated upper elementary students (ages 9-11 yrs) and adolescents (aged 12-18 yrs) using an online survey. The survey items included key demographic factors, Mukbang viewing frequency and duration, frequency of main meal consumption, commonly consumed foods, and the validated NQ, which was used to assess food intake quality. Multiple linear regression analysis was used to explore the link between Mukbang viewing and nutritional habits. RESULTS: Weekly Mukbang viewing time was significantly correlated with eating habits after adjusting for gender, age, physical activity frequency past week, household income, and primary caregiver's level of education. Increased Mukbang viewing time correlated with reduced frequency of breakfast (P for trend < 0.001) and dinner (P for trend = 0.012), while the frequency of eating out (P for trend < 0.001) and late-night snacking (P for trend = 0.008) increased. Higher Mukbang viewing time notably decreased scores in the moderation domain (P for trend < 0.001), in the practice domain (P for trend = 0.031), and overall NQ (P for trend < 0.001). It also significantly elevated intake of sweets (P for trend = 0.001), Korean-style street food, Western-style fast food, instant noodles, sweetened beverages, caffeinated beverages, and fruit and vegetable juices (P for trend < 0.001). CONCLUSION: This study identifies a negative correlation between Mukbang viewing and eating habits among Korean children and adolescents. The results indicate the importance of incorporating children and adolescents' media usage and environmental factors on dietary education and the development of policy programs.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.635-641
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• 2003

A non-thermal pasteurization technology, high Pulsed Electric Field (PEF) has been thought to be a new alternative processing technology instead of heating. The objective of this study was to examine and compare the effect of PEF and High Temperature Short Time (HTST) treatments on the physicochemical, microbiological and sensory characteristics of citrus juices. Total sugar and titratable acidity values of fresh citrus juice and two treatments were not significantly different each other at p<0.05. The concentration of vitamin C in fresh citrus juice $(31.2{\pm}0.59\;mg%)$ was not significantly different with the value of PEF treatment $(29.4{\pm}0.75\;mg%)$ but was significantly higher than the value of HTST treatment $(27.4{\pm}0.75\;mg%)$. The color values (L, a, and b) in PEF treatment were significantly lower than the fresh citrus juice, but were higher than the values of HTST treatment. Both total bacterial cell counts $(6.65\;{\pm}\;0.08\;log_{10}(cfu/mL))$ and yeast counts $(7.79{\pm}0.07\;log_{10}(cfu/mL))$ in fresh citrus juice were significantly reduced by PEF $(1.39{\pm}0.14,\;2.42{\pm}0.1\;log_{10}(cfu/mL))$ as well as HTST treatment (0, 0). PE activity of fresh citrus juice $(1.3{\pm}0.12\;units/mL)$ was significantly reduced by PEF treatment $(0.11{\pm}0.01\;units/mL)$ and was totally inactivated by HTST treatment. Sensory evaluation scores in flavor, taste and overall acceptability between the fresh and PEF treated citrus juices $(7.2{\sim}7.5)$ were not significantly different but the values of HTST treatment $(5.1{\sim}5.8)$ were lower than others. Consequently, PEF treatment is thought to be a good alternative pasteurization method for fresh citrus juice to HTST treatment due to its strong pasteurization effect, reduced destruction of nutrients and good sensory characteristics.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.242-253
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• 1980

This experiment was carried out to evaluate the possibility of wine-making with Elderberry cultivated in Korea. The results obtained are summarized as follows: 1. The Elderberry fruits were composed of 82.8% moisture, 0.82% crude fat, 3.73% crude protein and 0.83% crude ash. 2. The Elderberry juices were composed of 9.2% sugar, 0.62% total acidity (as tartaric acid), pH 4. 46 and the percentage juice extraction ratio from fruits was 61.4%. 3. In fermentation experiments carried out with two strains, Saccharomyces cerevisiae ellipsoideus showed better characteristics for wine-making than Saccharomyces cerevisiae montrachet. 4. In fermentation experiments carried out with Saccharomyces cerevisiae ellipsoideus under different storage conditions, frozen fruits showed better characteristics for wine-making than dried fruits. 5. In fermentation experiments carried out with Saccharomyces cerevisiae ellipsoideus under different pressing times, red wine and pink wine showed little difference. 6. The results of organic acid contents determined by gas chromatography showed that citric acid was the main acid for frozen fruit, and lactic acid for both dried fruit and wines. 7. Sensory evaluation showed that the wine pressed at the 3rd day had the best palatability but the wine fermented with the dried fruits had the worst among the tested.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.372-376
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• 2009

Physicochemical changes in persimmon were examined during natural organic acid fermentation. Major organic acids in raw persimmon juices were lactic acid (980 mg%) and acetic acid (245 mg%). The content of acetic acid was continuously increased during the whole period of fermentation up to 3 years. Glucose was the dominant free sugar, but the content was decreased after 20 days of fermentation. Most of the glucose was converted to ethanol until 40 days after initiation of acid fermentation. L- and a values of Hunter's color in fermented persimmon juice, which was naturally exuded from persimmon fruit as fermentation continued, increased gradually, while b value decreased. Acetic acid (1584 mg%) was the most abundant organic acid followed by lactic acid (712 mg%) and citric acid (48 mg%) in a persimmon fruit juice after completion of 3 year fermentation. A minute amount of residual free sugars, mainly glucose, even after 3 years of fermentation may cause changes in quality characteristics while storage for edible use.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.767-774
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• 1998

This study has been carried out to measure the amount of the daily intake by Korean on preservatives (Dehydroacetic acid, Benzoic acid and ρ-Hydroxybenzoic acid asters) in foods. The amounts of preservatives were determined by HPLC in foods such as butter, cheese, margarine, aloe gel, carbonated beverages, mixed beverage, ginseng beverage, red ginseng drink, soy sauce, fruit and vegetable juices (except unheated fruit-vegetable juice), vineger, seasonings, fruit and vegetables only on the peel, fruit wine, rice wine and unrefined rice wine. The recovery ranges were found to be 99.2% for dehydroacetic Acid, 95.8% for benzoic acid and $94.2{\sim}97.2%$ for ${\rho}-hydroxybenzoic$ acid in foods, respectively. The data of average food intake for each food items per capita per day were obtained from the report of national nutrition survey carried by the Ministry of Health and Welfare in 1997. The detected number of samples and average intake range of preservatives have been figured cut to $ND{\sim}290.0{\;}ppm$ for dehydroacetic acid, $ND{\sim}400.0{\;}ppm$ for benzoic acid and $ND{\sim}93.9{\;}ppm$ for ${\rho}-hydroxybenzoic$ acid esters, respectively. Estimated daily intake (EDI) of each additives per capita per day were shown as follows; 1.56 mg for dehydroacetic acid, 2.25 mg for benzoic acid and 0.44 mg for ${\rho}-hydroxybenzoic$ acid esters in total respectively and these values were evaluated to be much lower than that of FAO/WHO's acceptable daily intake (ADI) $0{\sim}5{\;}mg/kg$ b.w./day for benzoic acid and $0{\sim}10{\;}mg/kg$ b.w./day for ${\rho}-hydroxybenzoic$ acid esters.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.416-421
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• 1997

Physicochemical properties of six cultivars of Cheju citrus fruits were investigated according to the harvest date. The fruit index of Citrus. unshiu Marc. var. miynawa, C. $natsudaidai{\;}H_{AYATA}$ and C. sudachi ranged from 1.14 to 1.38 with oval form. The fruit index of C. grandis OSEECK, C. aurantiun LINN and C. platymamma. Hort. SWINGLE ranged from 0.89 to 1.03 with a round form. The fruit weight showed the heaviest in C. grandis, followed by C. natsudaidai, C. aurantiun, C. unshiu, C. platymamma and C. sudachi. The rate of flesh showed the highest in C. unshiu, followed by C. platymamma, C. nat녀daidai, C. sudachi, C. grandis and C. aurantiun. The ratio of juice showed the highest in C. unshiu, followed by C. sudachi, C. platymamma., C. natsudaidai,, C. grandis, C. aurantiun. C. unshiu and C. platymamma, which showed a possibility to be used as raw materials for juices. The soluble solid and the Brix/acid ratio of all the varieties increased as the fruits ripen. Especially those of C. unshiu and C. platymamma were high(10.39, 7.67) in full ripe compared to other varieties. Acid content of C. natsudaidai, C. aurantiun, C. grandis and C. sudachi was sustained higher than $3{\sim}5%$ from the middle of September to the middle of January, and there was the possibility of manufacturing aromatic products like citrus vinegar. The C. sudachi contained the highest content of vitamin C,77.48 mg/100 g. The correlation between vitamin C extraction and season was insignificant. Rind and color value of all varieties were investigated, and the value of the L, a and b increased as the fruits were ripen. The value of a of rind of C. $natsudaidai{\;}H_{AYATA}$ and C. grandis until the end of November was negative. This means that their color was not presented by November since the chlorophyll was in the rind, unlike the colors of the rind of C. unshiu, C. sudachi and C. platymamma which were completed by that time.

• Journal of the Korean Dietetic Association
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• v.10 no.3
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• pp.300-308
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• 2004

The purpose of this study was to examine the effect of diabetes education on diabetic management by determining the changes of the knowledge and practice for diet therapy and blood glucose level pre-training and post-training. Statistical data analyses were completed using the SPSS 11.0 program. The results can be summarized as follows : The average age of the subjects was 52.8 years old, the period of suffering from diabetes was 7.9 years and 31% of the patients had a history of diabetes in their family members. In life style for self-management, they showed lower levels in drinking post-training, and significantly higher exercise levels post-training (P<0.05). Regarding the level of knowledge for diet, they showed significantly higher levels post-training in eight items such as importance of diet therapy for diabetes (p<0.005), principle of diet therapy (p<0.005), nutrient composition of foods (p<0.005), carbohydrate composition of foods (p<0.005), calorie prescribed to themselves (p<0.001), exchange units prescribed to themselves (p<0.005), exchange food items and exchanges units of cereal & grains (p<0.005) and exchange food items and exchanges units of fruit & juices (p<0.005). Regarding the practices of diet, they showed significantly higher levels of practice in keeping permitted meal size (p<0.005), using food exchange list (p<0.005), keeping exact meal times (p<0.001) and restricting most foods to eat (P<0.01) post-training. When measuring their bodies, average weight was lower post-training. Obesity was significantly lower post-training (p<0.01), and blood pressure both in systolic and diastolic was lower. Postcardinal-2hour blood glucose level decreased significantly from 268.4$\pm$98.9 pre-training to 180.9$\pm$48.4 post-training (p<0.001).

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1527-1527
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• 2001

Glucose, fructose and sucrose being the main sugars that can be found in natural fruit juice. Many instrumental methods, such as GC, LC, electrochemical or spectrometric methods provide information about both the total content of sugars and the specific concentration of each carbohydrate[1]. The simplicity of sample handling and measurement in the near IR(NIR) wavelength region, which allows the use of long pathlength, optical glass cells and optical fibers, makes NIR a good alternative for sugar determination [2]. In the present study, six varieties of persian grapes were harvested at intervals through august to october and analysed for sugars by NIR. The results were processed by principal component regression (PCR) and partial least squares (PLS) analysis. Sample juice was prepared by squeezing through gauze from crashed grape. This solution was treated by zinc ferrocyanide prior to analysis in order to eliminate colored compounds and all optically active nonsugar substances. For glucose and fructose the most characteristic wavelengths were 1456nm corresponding to the first harmonic O-H stretching and the second at 2062nm corresponding to O-H stretching and deformation; secondary characteristic combination bands were also seen at 2265 nm (O-H and C-C stretching) and at 2240 nm (C-H and C-C stretching). However these spectra were taken over a wavelength range from 1100-2500nm at room temperature of 25-$30^{\circ}C$. To test the accuracy of the described procedure, samples of six varieties of grape were analysed by the proposed NIR and a standard method[2]. Good agreement were found between these two sets of the results. To perform the recovery studies , samples of grape juices previously analysed by the proposed method, were spiked with known amounts of each individual sugars and then analysed again. Relative standard deviations varied from 1.4 to 1.8% for six independent measurements of individual and total sugar concentration. In the analysis of real and synthetic samples, precise and accurate results were obtained , providing accuracy errors lower than 1.9% in all cases. Average recoveries of ${97}{\pm}{4%}$ for total sugar and between ${95}{\pm}{5%}$ and ${99}{\pm}{2%}$ for sing1e sugars demonstrate the applicability of the methodology developed to the direct analysis of grape Juice.