• Food Science and Biotechnology
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• v.18 no.2
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• pp.494-499
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• 2009

To improve phenylalanine ammonia lyase (E.C.4.3.1.5-PAL) activity in recombinant Escherichia coli, Some approaches for improving phenylalanine ammonia lyase (PAL) activity in recombinant E. coli were developed following preliminary studies by means of response surface method. The results shown that permeabilization with combination of Triton X-100, cetyl trimethyl ammonium bromide (CTAB), and acetone enriched cellular recombinant PAL activity significantly, which improved over 10-fold as compared with the control (untreat cell), as high as 181.37 U/g. The optimum values for the tested variables were Triton X-100 0.108 g/L, CTAB 0.15 g/L, and acetone 45.2%(v/v). Furthermore, a second-order model equation was suggested and then validated experimentally. It was indicated that addition of surfactants and organic solvents made the cells more permeable and therefore allowed easier access of the substrate to the enzyme and excretion of the product, which increased the rate of transport of L-phenylalanine and trans-cinnamic acids. These improved methods of PAL activity enrichment could serve as a rich enzyme source, especially in the biosynthesis of L-phenylalanine.

• The Korean Journal of Food And Nutrition
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• v.6 no.3
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• pp.158-168
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• 1993

For the conversion of WAD to NADP, Immobilized Brevibacterium ammoniagenes cells with NAD kinase was coupled with ATP-generating system by acetate kinase. The membrane permeability of B. ammoniagenes was improved by toluene treatment of cells. The toluene treated B. ammoniagenes cells were immobilized for stable enzyme activity. Partially purified acetate kinase was used in the reaction system. The optimum conditions for the efficient conversion of UAD to WADP by energy-coupled system were investigated. B. ammoniagenes cells treated with toluene for the Improvement of membrane permeability showed 4.5 fold improved permeability in the conversion of NAD to NADP compared with Intact cells. 3% k-carrageenan as the immobilization matrix of B. ammoniagenes showed the best efficiency for the conversion of NAD to NADP The optimum conditions for the WAR to WARP conversion reaction coupled nth ATP-generating system were 10mM acetylphosphate, 5mM ADP 200mM inorganic phosphate, 10mM MgCl2, 250mg/ml Immobilized cells, 49.3mUnit/ml acetate kinase, pH 7.5 and 37$^{\circ}C$. Under the optimum conditions, 72% of 5mM(340mg/ml ) NAD was converted to UADP In 12 hours.

• The Korean Journal of Food & Health Convergence
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• v.5 no.4
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• pp.1-10
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• 2019

Significant low knowledge and poor attitudes on complementary feeding undermine the practices. This study was a cluster randomized controlled trial in which 284 study participants were assigned into two groups. One intervention group and a control group in a ratio of 1:1. Nutrition education on complementary feeding was carried out among the caregivers in the intervention group but the caregivers in the control group were not educated. To determine complementary feeding knowledge and attitudes, data was collected from caregiver at baseline, midline and at endline using researcher-administered questionnaires. Quantitative data were analyzed using SPSS version 22.0. From the analysis, there was a significant difference in complementary feeding knowledge of the caregivers after the intervention. The baseline difference was -0.06, the midline difference was 3.85 the endline difference was 4.00 and the DID of the baseline and endline was 4.06 which was significant at p=0.001. There was a significant difference in the attitude of the caregivers towards complementary feeding at baseline (-0.14), midline (2.09), endline (3.82) and the DID of baseline and endline was 3.96 which was significant at p=0.001. The intervention improved the caregivers' knowledge on complementary feeding and it improved the attitudes of the caregivers towards adequate complementary feeding.

• Korean journal of food and cookery science
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• v.31 no.6
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• pp.696-702
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• 2015

Rice dumpling shells were prepared with different levels of hydrocolloids, such as hydroxypropyl methyl cellulose (HPMC), and potato starch. After steaming, the physical, sensory, and cooking properties of the shells were measured. Increasing the amount of potato starch decreased the pasting temperature and increased the peak viscosity. With the addition of hydrocolloids, water absorption and cooking loss for the rice dumpling shells decreased significantly. For the textural properties, the rice dumpling shells with hydrocolloids showed lower hardness and higher springiness than the control, and especially, 10% potato starch and 3% HPMC addition (P10H3) improved the texture of the rice dumpling shells the most. The sensory results seemed to be affected more by the addition of potato starch than HPMC, and over 15% addition of potato starch significantly decreased the quality of the rice dumpling shells. By addition of adequate amount of hydrocolloids (3% HPMC and 10% potato starch), the sensory quality of rice dumpling shells can be effectively improved.

• Biomedical Science Letters
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• v.24 no.3
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• pp.230-238
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• 2018

Human enteric Adenovirus-41 (HuEAdV-41) causes gastroenteritis, which detected by the polymerase chain reaction (PCR) base diagnostic system for clinical, food, environmental, fish and shellfish samples. We developed improved PCR and nested PCR primer set which had high specificity, sensitivity and reduced times. In this study, we compared seventeen conditions reported in the previous study that was using the PCR based HuEAdV-41 detection system, and non-enteric Adenovirus were detected in nine conditions. The most sensitive detection condition was up to 25 copies however it took 184 minutes of PCR reaction time. In this study, the PCR primer set developed had same level of sensitivity, it reduced the time of detection for clinical, food and seafood samples to 112 minutes. Developed nested PCR primer set needed 112 minutes but detected up to approximately 1 copy. In addition, developed PCR and nested PCR primer set was validated with twenty samples of underground water at random, of which ten samples showed specific band without non-specific reaction. We expect this study will be used to diagnose HuEAdV-41 from various samples.

• Korean Journal of Food Science and Technology
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• v.16 no.3
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• pp.353-357
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• 1984

The myofibril prepared from PSE (pale, soft, exudative) porcine meat was modified by reacting with succinic anhydride and the chemical and functional properties of modified myofibrils were investigated. $No\;Ca^{2+}-and\;Mg^{2+}-ATPase$ activity were observed irrespective of the degree of succinylation. Isoelectric point of the succinylated myofibril changed to around pH 3 from the pH 5 of unmodified myofibril. Salt soluble property was not affected by changing the salt concentration. The modified myofibril in aqueous solution did not coagulate during heating at $98^{\circ}C$ for 10 min. Water absorption ability was not improved but emulsion capacity was improved a little by succinylation.

• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.228-234
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• 2022

Various types of tea have been cultivated to obtain different flavors and enhance their functional properties. The objective of this study was to investigate the physicochemical properties of γ-aminobutyric acid (GABA) teas produced from commercial Korean green, white, and black teas. The concentration of total minerals was reduced in GABA green tea and GABA white tea but was improved in GABA black tea. The essential, non-essential, and total free amino acid contents were remarkably increased in the GABA teas. The amino acid GABA content was increased by 561.00 and 294.20 times in GABA white tea and GABA black tea, respectively. The antioxidant potential was not reduced, although the total polyphenol and total flavonoid contents decreased in GABA green tea and GABA black tea. The results indicated that the overall nutritional value of commercial green, white, and black teas could be improved by processing them into GABA teas.

• International Journal of Industrial Entomology and Biomaterials
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• v.44 no.2
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• pp.37-43
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• 2022

Silkworm food has been found to be effective for dementia, liver function, lowering blood sugar, and possesses antioxidant properties, which has been attracting attention as a health functional food. In this study, methods for enhancing the functionality of silkworms were explored and the production potential of high-functional silkworms was analyzed. For enhancing antioxidant activity, ascorbic acid, caffeic acid, laminarin, and glutathione were injected or fed to 5th instar silkworms, and the antioxidant activity of silkworm extract was comparatively analyzed. There was no significant change in polyphenol and flavonoid content, but it was confirmed that 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability, superoxide dismutase-like activity, and reducing power were slightly increased after injection of ascorbic acid, caffeic acid, and glutathione. To confirm the increase in antioxidant efficacy through feeding, an inducer was mixed with sucrose and sprayed on mulberry leaves. As a result, the growth rate of silkworms improved and all indicators of antioxidant activity were improved in silkworms fed with ascorbic acid and glutathione. Considering these results, producing high-functional silkworms was deemed possible.

• Food Science of Animal Resources
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• v.43 no.3
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• pp.412-427
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• 2023

The effects of wet-aging using a commercial refrigerator (CR, 4℃) and a pulsed electric field refrigerator (PEFR, 0℃ and -1℃) on the quality of sous vide pork loin were analyzed. The moisture and fat contents, pH, CIE L^*, CIE b^*, chroma, and shear force of the wet-aged samples were lower than those of the raw meat samples, whereas the water holding capacity (WHC) was higher. The PEFR group showed higher pH, CIE b^*, chroma, and WHC and lower weight loss than the CR samples. Electronic nose analysis indicated that positive flavor compounds were induced whereas negative flavor compounds were inhibited in the PEFR group. Wet-aging increased the sourness, saltiness, and umami of sous vide pork loin; the PEFR 0℃ samples showed the highest umami. Sensory evaluation indicated that wet-aging improved the color of sous vide pork loin. The PEFR 0℃ samples were rated higher than the raw meat and CR samples for all sensory traits. In conclusion, sous vide after wet-aging using a PEFR improved the quality of pork loin.

• Human Ecology Research
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• v.60 no.4
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• pp.565-576
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• 2022

The purpose of this study is to identify the effect of Home Economics Instruction applying Flipped and Problem-Based Learning (FPBL) on Korean middle-school students' metacognition skill. The study uses a pre-post design test of the same group. There were 151 participants (77 male and 74 female) who were middle-school students in the third grade. Two hours of classes on 'Food Selection and Storage' were given per week for three weeks - a total of six hours. Analysis using the t-test revealed a statistically significant difference between the pre-test and the post-test, supporting the conclusion that participating in the class improved the metacognition, food selection, and storage behavior scores of the middle-school students. All area scores and overall averages of metacognitive sub-elements such as planning, monitoring, regulation, and evaluation also improved after taking FPBL classes. From the results of this study, Home Economics Instruction applying FPBL is an effective teaching method for improving middle-school students' metacognition.